2025 CAP Congress / Congrès de l'ACP 2025

8 Jun 2025, 07:00 → 13 Jun 2025, 23:59 America/Winnipeg

Welcome to the CAP2025 Indico site. This site is being used for abstract submission and congress scheduling.     Bienvenue au site web Indico pour ACP2025. Ce site servira à la soumission de résumés et à la préparation de l'horaire.

Sunday 8 June

12:00 Congress Registration | Inscription au congrès

Student Event

CAP Board, Council and Friends Social | Réunion du conseil d'administration, du conseil et des amis de l'ACP

Student Icebreaker Event

CAP Past Presidents' Working Dinner Meeting | Réunion et souper des ancien(ne)s président(e)s de l'ACP

Monday 9 June

07:30 Congress Registration and Information (07h30-17h30) | Inscription au congrès et information (07h30-17h30)

08:30 Registration/Tour sign-up for HS/Cegep Teachers Workshop

Congress Welcoming Remarks (08h40-09h00) | Ouverture du Congrès (08h40-09h00)

High School / Cégep Teachers' Day A.M. Workshop Sessions | Journée des enseignants du secondaire et des cégeps sessions

08:45 Welcome / Bienvenue

09:00 "Two-Eyed Seeing": Dynamical evolution across galactic scales and the future of big science - Kathryne Daniel, University of Arizona

09:00 Using Big Science Research to Deliver Education Outcomes - Tracy Walker, Canadian Light Source

09:45 Break

10:00 The Quantum Explorations Student Toolbox (QuEST)

10:00 Tools for Teaching Science - Patrick Kossmann, Perimeter Institute for Theoretical Physics

1 Bringing SNOLAB science into your classroom

Dive deep into the science "Bringing SNOLAB science into your classroom"
taking place 2km underground at SNOLAB; Canada's underground science laboratory specializing in astroparticle physics. In this session educators will get an update on science underway at the facility and learn about opportunities to bring that research into classrooms through virtual class visits.

Speakers: Blaire Flynn (SNOLAB), Juliette DeLoye (SNOLAB)

11:20 Fantastic Physics Pro-D - Joe Muise, St. Thomas More Collegiate

M-PLEN1 Plenary Session | Session plénière - Kathryne Daniel, U. of Arizona

2 “Two-Eyed Seeing”: Dynamical evolution across galactic scales and the future of big science

“Two-eyed seeing” was coined by Albert Marshall, a Mi’kmaq elder, to describe the depth of perspective gained when perceiving the world through both an Indigenous and Western lens. Using this framework, I will describe my approach to science, which focuses on emergent behavior in disk galaxies as a driver of evolution. Dynamical resonances are essential to the evolution of disk galaxies. These resonances arise in the presence of massive structures, like a bar, spiral arms and satellites, and they reshape a galaxy as they diffuse, shepherd and rearrange orbits and stellar populations. This talk will highlight a collection of methods that together enable us to connect orbital dynamics to morphological evolution. The end of this talk will touch on the status of the next generation gravitational wave observatory in the US, Cosmic Explorer. In particular, how our approach to site selection embodies two-eyed seeing and why our approach is critically important to the future of big science.

Speaker: Kathryne Daniel (University of Arizona)

09:45 Health Break | Pause santé

(DASP) M1-2 Magnetosphere and Magnetospheric Dynamics | Magnétosphère et dynamique magnétosphérique (DPAE)

3 Real Heights of SuperDARN Echoes Estimated From Electron Density Data

The actual heights of the SuperDARN echoes have never been systematically estimated. The main difficulty is that the HF signals experience a strong ionospheric refraction, so that even accurate angle-of-arrival measurements provide information only on their virtual height. In this study, we use elevation angle data at 10- and 12-MHz frequency bands from Rankin Inlet (RKN) SuperDARN radar to estimate electron density values at the scatter locations. Matching these densities with those from collocated altitudinal profiles measured by the Resolute Bay incoherent scatter radar (RISR) allowed for estimation of the actual height of the HF radar echoes. Our analysis show that typical heights of RKN echoes are at 220-250 km above the ground. The echoes are, on average, 40-50 km below the F region peak, with larger differences occurring at larger maximum F-layer densities. Echoes in the 12-MHz frequency band are typically 5 km higher than those at 10 MHz. Some minor tendencies in the diurnal variations of echo heights and seasonal differences are identified and discussed.

Speaker: Dr Sasha Koustov (U of Saskatchewan)

4 Comparison of sporadic E layers obtained via modeling and measured by CHAIN ionosondes

Sporadic E-layers are dense thin layers of metallic (Mg+, Fe+, Na+, Ca+) ions of meteoritic origin which may form at altitudes 90-150 km. These structures are important for radio communications and remote sensing applications because they significantly alter propagation of radio waves. A 3D numerical model of high latitude ionosphere has recently been developed at the University of Alberta. We apply the model to simulate ionosphere evolution during July 9-12, 2011. In this simulation, dense sporadic E-layers form at altitudes 100-120 km, mostly in the night sector, between MLT 10pm and 2am, for GEO latitudes between 70 and 80 degrees North. This matches the statistical data for high latitudes for the June-August season given in [Aylett et al (2025), JGR, 130, e2024JA033044]. The modelled density profiles are compared with ionosonde data from Cambridge Bay and Resolute Bay stations of the Canadian High Arctic Ionosonde Network (CHAIN). The time, altitude, and magnitude of sporadic E-layers calculated with the model for the Cambridge Bay show reasonable agreement with the measurements. The agreement with the Resolute Bay station, which is at a very high geomagnetic latitude of 82.61 degrees North, is not so good. Probable reasons for this may be the simplified tilted dipole configuration of the geomagnetic field used by the model and the absence of the vertical neutral wind in the simulation (the neutral winds are provided by the HWM model). This is a very recent work that we have just began to investigate. It demonstrates that while the 3D ionospheric model is capable of predicting sporadic E-layers, it requires extensive validation.

Speaker: Dmytro Sydorenko

5 Observations of the ionospheric response to the April 2024 total solar eclipse over New Brunswick

The Earth’s ionosphere can be a nuisance for some navigation and communications systems. Knowledge of the state of the ionosphere helps improve the operational capabilities of such systems. The effect of solar eclipses on the state of the ionosphere leading to a significant decrease of the ionization level and thus losses of free electrons has been observed and studied for decades. Nevertheless, to date none of the existing models can fully predict the change in the 3D electron density distribution caused by a solar eclipse.
To measure the 3D effect of the electron density fluctuation in response to the April 2024 total solar eclipse, a network of low-cost global navigation satellite systems (GNSS) receivers called EclipseNB, in addition to a network of high-frequency (HF) ionospheric sounders, were designed, assembled and deployed by the Radio and Space Physics Laboratory at the University of New Brunswick during the period from April 2023 to March 2024. The infrastructure of EclipseNB is a provincial network consisting of fifteen low-cost GNSS receivers to monitor the plasma of the upper atmosphere during the solar eclipse. A small network of HF sounders consisting of one vertical and two passive oblique ionospheric sounders were also designed and strategically installed such that their ionospheric reflection points were located along the eclipse path of totality. GNSS raw observables were collected at a one-second sampling interval, while vertical and oblique ionograms obtained from HF instruments were collected every two minutes over the three days before, during, and after the eclipse.
The results of the ionospheric response in terms of the total electron content (TEC) obtained using GNSS receivers, as well as the characteristics of the ionospheric layers retrieved from HF sounders will be presented and quantitative analysis of the response provided.

Speaker: Anton Kashcheyev (University of New Brunswick)

6 April 2024 Solar Eclipse Effects on Ionospheric Density and Radio Propagation

This study examines effects of the April 2024 total solar eclipse on ionospheric electron density and HF radio propagation, using multi-instrument observations and the physics-based SAMI3 model (SAMI3: A Model of the Ionosphere). We compare ground-based ionosonde measurements from across North America, including a newly installed station at Wright-Patterson Air Force Base, which was located under the path of totality, to SAMI3’s predictions of altitude profiles of plasma density at these ionosonde locations. We also use data from the HamSCI Solar Eclipse QSO Party (SEQP), which includes radio communications reported by ham radio operators and global automated receiving networks (e.g., WSPRNet, the Reverse Beacon Network, and PSKReporter). Ham radio datasets, along with PHaRLAP raytrace modeling, are utilized to infer the ionospheric and HF radio responses to the solar eclipse. Our findings suggest that the eclipse driven ionospheric electron density changes are symmetric in the E-region but asymmetric and delayed in the F-region. The eclipse increased the range of radio communications in the lower HF bands (3.5, 7, 10 MHz) but decreased long-range communications in the higher HF bands (21, 24, 28 MHz). Ham radio datasets show an earlier opening of radio links between the US and Europe on the day of the eclipse, suggesting a combined effect of the sunset terminator and the eclipse shadow during the later phase of the eclipse.

Speakers: Gareth Perry (New Jersey Institute of Technology), Kuldeep Pandey (New Jersey Institute of Technology)

7 Density structures observed by the Radio Receiver Instrument on e-POP/Swarm-E

The Radio Receiver Instrument (RRI) on e-POP/Swarm-E detects ground-based HF radio waves. As HF radio waves traverse the ionosphere, variations in ionospheric density influence propagation. Using the Faraday rotation approach with RRI measurements enables the determination of density variations along the propagation path. The high sampling rate of RRI allows for the detection of plasma structures across multiple scales from a transmitter in Ottawa. Observed structures have scales ranging from half a km to 1500 km. Small-scale variations exhibit magnitudes comparable to large-scale variations, but remain confined to narrow latitude bands. In addition, the scale sizes from GPS Total Electron Content (TEC) suggest similar scale sizes as observed by RRI. The variation of density scale sizes extracted from RRI gives more insight into the structure of the ionosphere and can lead to more accurate modelling for HF radio wave propagation.

Speaker: Dr E. Ceren Kalafatoglu Eyiguler (University of Saskatchewan)

8 The new physics unveiled by the ICEBEAR radar in conjunction with with other auroral observations

The multiple interferometry links of ICEBEAR have revolutionized how we look at the radar aurora. At first, we confirmed expectations from previous work: strongly field-aligned irregularities , a strong link with auroral indices, a preferred 100 to 110 km altitude range and Doppler shifts normally (not always) slower than the ion-acoustic speed Cs. The latter has stimulated theoretical work on the meaning of a saturation at Cs and on circumstances that break this rule, with Doppler shifts at the line-of-sight component of the ExB drift. Not expected was a clear tendency for the radar echoes to be in clusters separated by 1 to 5 km. This trend was linked to observed precipitation patterns. It could also relate to modulations of Farley-Buneman waves by gradient-drift waves. Monitoring radar echoes locations relative to the aurora, the echoes never come from centers of precipitation, being found along arc boundaries. More importantly and unexpectedly, the clusters motions follow the ExB drift of the plasma. The contradiction between observed Doppler shifts and much faster cluster motions was attributed to the ephemeral nature of unstable 3-m structures. Also, radar echoes are often found on only one side of auroral arcs; in those cases, the motion is very fast, reaching up to a few km/s. We explained these one-sided fast flows through a Cowling conductivity mechanism. Finally, we established that unstable situations deep in the magnetosphere map to the ionospheric location of radar echoes. In the process we also identified a cleft boundary signature in radar echo patterns.

Speaker: Jean-Pierre St-Maurice

9 Variations of SuperDARN ground scatter occurrence rate in the polar cap

Frequent occurrence of ground-scatter (GS) is a common feature of SuperDARN observations. This study extends previously published work on GS by focusing on data collected by the polar cap radars at Inuvik and Clyde River. One of the objectives is to identify data trends affected by electron density variations in the ionosphere. For the F region GS, both radars show strong solar cycle effect with variations of GS occurrence rate by a factor of 2 consistent with changes of the peak electron density. Seasonally, GS is more frequent in summer and at nighttime. Nighttime GS occurrence rates show clear correlation with increases in the electron density. Such correlation is less obvious during daytime. Diurnally, GS occurrence rates at near noon hours have clear maxima in winter but minima in summer. Partially, the summer reduction effect can be related to the blocking effect of the E region prohibiting HF radio wave propagation into the F region as evidenced by the enhanced occurrence of GS received at shorter ranges, via E region. GS received via E region is more frequent during nighttime, and no solar cycle effect is evident.

Speaker: Mr Mehdi Ghalamkarian Nejad (U of Saskatchewan)

(DGEP) M1-1 Celebrating Indigenous Physicists | Célébration des physiciens indigènes (DEGP)

10 Indigenizing the Drake Equation.

The Drake Equation is a thought experiment whose purpose is to understand the ingredients necessary for life and advanced technological civilizations to exist on other worlds in our galaxy. However, beyond reflecting on life on Earth we have no knowledge of many of these ingredients, such as the number of planets that have life, the number of with intelligent life, the number with advanced civilizations, and the lifetimes of these civilizations. In this talk I will review the Drake Equation and the biases that scientists have traditionally had in discussing this equation and how it has led to the current searches of biological and technological signatures. I will discuss how the Drake Equation looks different if we consider it through the lens of Indigenous methods and sciences and how these methods would lead to a dramatically different view of life in our Galaxy.

Speaker: Hilding Neilson (Dept of Physics & Physical Oceanography, Memorial University of Newfoundland & Labrador)

11 The Society of Indigenous Physicists

The Society of Indigenous Physicists (SIP) was founded in 2020 as a collective of mutual support, where we are connected by our dual identities as Indigenous and physicists. SIP’s mission is to support Indigenous physicists through an organization that uses culturally relevant community practices so that we can find belonging, grow, and offer our unique contributions. In this talk, I will share our origin story and ways in which SIP supports Indigenous astronomers in the form of a counter-space, representation, mentorship, awards, and financial support.

Speaker: Kathryne Daniel (University of Arizona)

11:15 invited speaker abstract to come - Kyle

11:45 Discussion / Networking

(DAMOPC) M1-3 Cold atoms and Magnetometry | Atomes froids et magnétométrie (DPAMPC)

12 Developing Canada’s First Transportable Quantum Gravimeter

Classical free-fall gravimeters based on optical interferometry have been a cornerstone of geophysical research and exploration for decades. However, they suffer from long-term instability, mechanical drift, and they cannot be operated on moving vehicles. The first commercial quantum gravimeters are now available on the market, largely due to advances in lasers and ultra-high vacuum technologies. These instruments use matter-wave interferometry with a laser-cooled gas of neutral atoms to measure gravity down to the micro-Gal ($10^{-9}$ g) level. At the University of New Brunswick, we recently realized a table-top quantum gravimeter that will eventually act as a high-accuracy gravity reference for other instruments. We are also building a second quantum gravimeter that is designed to operate outside the lab for gravity mapping, positioning, and navigation applications. In this talk, I will give an overview of these instruments, their operating principles, and their key advantages over classical technologies. I will also discuss progress toward building Canada’s first transportable quantum gravimeter.

Speaker: Prof. Brynle Barrett (University of New Brunswick)

13 Photosynthetic Energy Transfer: Missing in Action (Detected Spectroscopy)?

Two-dimensional electronic spectroscopy (2DES) has emerged as a powerful tool for studying electronic structure and dynamics in systems ranging from photosynthetic complexes to liquids and solid-state materials. In recent years, motivated by the desire to make spatially resolved measurements and to correlate optical excitation with a wide range of observables, action-detected variants of 2DES have been developed that employ a fully collinear geometry, relying on phase cycling or phase modulation to extract the signals of interest. I will discuss our recent implementations of fluorescence-detected two-dimensional electronic spectroscopy (F-2DES) and our studies of the light-harvesting II (LH2) complex from purple bacteria as a model system to understand F-2DES’s ability to monitor energy transfer in multichromophoric systems. We demonstrate that the energy transfer process in LH2 is weak but observable in F-2DES, unlike in coherently detected 2DES where the energy transfer is visible with 100% contrast. We explain the weak signatures using a disordered excitonic model that accounts for experimental conditions. We find that the prominence of excited-state dynamics in action-detected spectroscopy offers a unique probe of excitonic delocalization in multichromophoric systems.

Speaker: Jennifer Ogilvie (University of Ottawa)

11:15 Discussion / Networking

(DCMMP) M1-4 Quantum and Topological Matter | Matière quantique et topologique (DPMCM)

14 Disordered Weyl semimetal as an array of coupled Hubbard chains

We demonstrate that a disordered magnetic Weyl semimetal may be mapped onto a two-dimensional array of coupled replicated Hubbard chains, where the Hubbard U is directly related to the variance of the disorder potential. This is a three-dimensional generalization of a similar mapping of the two-dimensional quantum Hall plateau transition to a one-dimensional Hubbard chain. We demonstrate that this mapping leads to the conclusion that the Weyl semimetal becomes a diffusive metal with a nonzero density of states at arbitrarily weak disorder, in agreement with recent work. We also discuss the absence of localization in strongly disordered Weyl semimetals from the viewpoint of this mapping.

Speaker: Anton Burkov (University of Waterloo)

15 A New Kind of Symmetry: Rethinking Anomalies in Quantum Systems

Anomalous symmetries play a central role in modern physics, from quantum field theories (QFTs) in the infrared to lattice models in the ultraviolet. Typically, anomalous symmetries are characterized by their appearance on the boundary of symmetry-protected topological (SPT) phases. However, folklore has also treated several other phenomena—such as the obstruction to a single symmetric, gapped, non-degenerate ground state, the inability to gauge the symmetry, and non-onsite realizations—as interchangeable signatures of anomaly.
In this talk, I will present a new class of symmetry that disproves these longstanding misconceptions. While our symmetry is not anomalous, it cannot be onsite, cannot be gauged, and nonetheless allows a unique, gapped, and symmetric ground state—demonstrating that these criteria are not equivalent. Our results clarify the relationships between non-onsiteness and non-gaugeability. I will also describe our classification of the obstructions to onsiteness and discuss implications for both quantum many-body systems and field theory.

Speaker: Wenjie Ji (McMaster University/Perimeter Institute)

16 Unveiling Berry curvature contributions to Hall current in $C_4K$ materials

We identify a new contribution to the conventional Hall effect that emerges in materials with $C_4K$ symmetry. This contribution originates from the effect of Berry curvature on phase space density. We demonstrate this using semiclassical equations of motion and identify corrections to Hall conductivity from Berry curvature and orbital magnetic moment effects. As an illustration, we build a minimal two-band tight-binding model with altermagnetic order, breaking $C_4$ and $K$ symmetries while preserving $C_4K$. The resulting Hall conductivity shows a kink at the altermagnetic phase transition temperature. This singular behaviour is due to the appearance of a Berry-curvature-driven contribution below the critical temperature. This effect may offer a simple transport-based signature for altermagnetic phase transitions.

Speaker: Tohid Farajollahpour (Brock University)

17 Nanoscale defects as probes of time reversal symmetry breaking

Nanoscale defects such as Nitrogen Vacancy (NV) centers can serve as sensitive and non-invasive probes of electromagnetic fields and fluctuations from materials, which in turn can be used to characterize these systems. In this talk, which is based on our recent work[1], we will specifically discuss how NV centers can directly probe time-reversal symmetry breaking (TRSB) phenomena in low-dimensional conductors and magnetic insulators. We argue that the relaxation rate of NV centers can vary dramatically depending on whether its magnetic dipole points towards or away from the TRSB material. This effect arises from the difference in the fluctuation spectrum of left and right-polarized magnetic fields emanating from such materials. It is perhaps most dramatic in the quantum Hall setting where the NV center may experience no additional contribution to its relaxation due to the presence of the material when initialized in a particular spin state but a large decay rate when initialized in the opposite spin state. More generally, we show in our work[1], that the NV center relaxation rate is sensitive to the imaginary part of the wave-vector dependent Hall conductivity of a TRSB material. We argue that this can be used to determine the Hall viscosity, which can potentially distinguish candidate fractional quantum Hall states and pairing angular momentum in TRSB chiral superconductors. We also consider Wigner crystals realized in systems with large Berry curvature and discuss how the latter may be extracted from NV center relaxometry.

Reference:
[1] De, Suman Jyoti and Pereg-Barnea, T. and Agarwal, Kartiek, arXiv:2406.14648 (2024).

Speaker: Dr Suman Jyoti De (McGill University, Canada)

NV_center_TRSB_abstract.pdf

18 Pressure Dependence of Spin Stripe Order in Nd-LSCO (x=0.125)

Nd$_{0.4}$La$_{1.6-x}$Sr$_x$CuO$_4$ (Nd-LSCO) is a prototypical high T$_C$ cuprate superconductor. At a hole-doping of x = 0.125 = 1/8, this compound is notable for displaying both static spin stripe order and charge stripe order, as well as a heavily suppressed superconducting T$_C$ ~ 3 K. Previous high-field transport [1] and thermopower measurements [2] have shown that the electronic properties of Nd-LSCO are highly sensitive to applied hydrostatic pressure, with a suppression of the pseudogap phase and a weakening of charge stripe order reported by P ~ 2 GPa. In contrast, the pressure dependence of the magnetic properties of Nd-LSCO has remained largely unexplored.

In this talk, we will present neutron diffraction measurements on high quality single crystal samples of Nd-LSCO (x=0.125), performed using the VERITAS and SNAP beamlines at Oak Ridge National Laboratory. These measurements allow us to characterize the pressure dependence of the structural and magnetic phase diagrams up to P = 1.7 GPa. We observe a remarkable enhancement of spin stripe order above 1 GPa, with magnetic scattering persisting up to room temperature at maximum pressure. Applied pressure also stabilizes the tetragonal crystal structure of NdLSCO, with a significant decrease in the HTT-to-LTO transition temperature (from ~450 K to ~300 K at 1.7 GPa) and a corresponding increase in the LTO-to-LTT transition (from ~68 K to ~80 K under the same conditions).

[1] N. Doiron-Leyraud et al, Nat. Commun. 8, 2044 (2017).
[2] A. Gourgout et al, Phys. Rev. Res. 3,023066 (2021).

Speaker: Patrick Clancy

(DNP) M1-5 Precision measurements in nuclear and particle physics | Mesures de précision en physique nucléaire et en physique des particules (DPN)

19 TUCAN developments toward first UCN production and nEDM experiment.

The TUCAN (TRIUMF UltraCold Advanced Neutron) collaboration aims for the construction of the world strongest ultracold neutron (UCN) source with a production rate of $1.6\times 10^{7}$ neutrons per second. The TUCAN source is based on a UCN production volume of superfluid helium (He-II), held at 1 K, coupled to a proton-driven spallation target. I’ll describe the functioning of the source and the results of the different phases of the experiment commissioning, including the steps leading to our first UCN production this summer.
The primary goal of the source is to feed an nEDM (neutron Electric Dipole Moment) experiment. The nEDM experiment is projected to be capable of a precision of $1\times 10^{-27}~e$cm, competitive with other planned projects, and a factor of ten more precise than the present world's best.I’ll present the recent magnetically shielded room construction and testing, progress towards efficient neutron transport, and magnetometry development.

Speaker: Alexis Brossard (TRIUMF)

20 Early Science Projections for Charged Pion Form Factor studies with ePIC at the Electron-Ion Collider

The Electron-Ion Collider (EIC) is the first new collider to be constructed in the 21'st century. When operational at Brookhaven National Laboratory in the early 2030's, it will allow hadron structure to be probed over a center of mass energy range of 20-140 GeV at very high luminosity ($10^{33}-10^{34}$~cm$^{-2}$s$^{-1}$). For $e-p$ collisions, this will be the first collider where both beams will be highly polarized. In the first years of the EIC science program, the capabilities and the variety of beam species and energies will be expanded as systems are commissioned. Much thought is going into the science reach of these first years of operation. Projections will be presented for $\pi^+$ form factor studies utilizing deep exclusive meson production in the first 7 years of the EIC science program. Such measurements may enable the direct observation of QCD's transition from confinement-dominated physics at large length-scales to perturbative physics at short-length scales.

Speaker: Prof. Garth Huber

21 BEAM ASYMMETRY FOR LIGHT MESON DECAYS IN GLUEX

The principal goal of the GlueX experiment at the Thomas Jefferson National Accelerator Facility is to search for non-qbar-q mesons, a construction not allowed by the simple quark model but predicted by Quantum Chromodynamics. Specifically, hybrid mesons, which result from the addition of a constituent gluon and are pictured as a qbar-qg state, will be accessed using the 8-9 GeV linearly polarized photon beam of GlueX and will be mapped as a function of their quantum numbers using partial wave analysis (PWA). Knowing the production mechanism is a key ingredient of PWA and is accessible through the beam asymmetry observable, which was extracted as a function of four-momentum transfer gamma p -> eta p, gamma p -> eta-prime p, and gamma p -> eta Delta+. Results from the full GlueX-I data set (2016-2020) over a wide range of -t have yielded a beam asymmetry close to unity, which indicates that the photoproduction process is dominated by rho and omega exchange.

Speaker: Zisis Papandreou (University of Regina)

CAP 2025 - abstract-BeamAsymmetry.pdf

22 The KDK+ experiment: measuring the rare positron emission of 40K

Potassium-40 ($^{40}$K) is a radioactive isotope of potassium that is found in rocks and the human body. It has two daughter isotopes, argon-40 ($^{40}$Ar), and calcium-40 ($^{40}$Ca). The most common decay of $^{40}$K is to $^{40}$Ca via $\beta$- decay, with a branching ratio of approximately 89.25%. The decay to $^{40}$Ar can occur through three methods, electron capture to an excited state of $^{40}$Ar, electron capture to the ground state of $^{40}$Ar, and $\beta$+ decay. The electron capture decay to an excited state of $^{40}$Ar is the most common of the three with a branching ratio of 10.55%. The decay via electron capture to the ground state of $^{40}$Ar was first measured by the potassium decay~(KDK) experiment, and found a branching ratio of approximately 0.1%. The final decay channel is through $\beta$+ decay. This is the rarest decay with a branching ratio of approximately 10$^{-5}$%. This decay was studied previously in the 1960s, however the experimental branching ratio does not agree with modern theoretical predictions. The KDK+ experiment is seeking to accurately measure this branching ratio by using a potassium salt dissolved in a liquid scintillator, and surrounded by 4 external $\gamma$ detectors. $\beta$+ signals are detected using a triple coincidence between the liquid scintillator, for the $\beta$+ interactions, then two back-to-back 511 keV detections in opposing $\gamma$ detectors. This talk presents an overview of the experiment, as well as the work that has been done to characterize the liquid scintillator.

Speaker: Nicholas Swidinsky (Queen's University)

(DNP) M1-6 Nuclear astrophysics | Astrophysique nucléaire (DPN)

23 Nuclear Astrophysics with Heavy-Ion Storage Rings

Storage rings connected to radioactive beam facilities offer unique experimental environments for measurements of rare decay modes that are otherwise not possible.

I will give an overview about some recent experiments at the Experimental Storage Ring at GSI Darmstadt, Germany, measuring rare decay modes that can only appear in highly-charged ions, for example the measurement of the bound-state beta-decay of 205Tl(81+) and the and its impact on the long-term solar neutrino flux in the LOREX project.

A new research stream that has received a lot of attention in the community in the past 10 years are astrophysically relevant reactions of stored ions with protons. This program is now successfully running and I will highlight some recent results. The next logical step is to investigate the possibility of neutron-capture reactions in inverse kinematics. I will outline some ideas for existing storage rings and which role a storage ring at TRIUMF could play in the future.

Speaker: Iris Dillmann

24 Electromagnetic transition rate measurement of 36Ar and 37Ar

Different predictive nuclear models, based on the nuclear shell model, have been developed to describe fundamental properties of all nuclei, such as energies and transition rates between nuclear states; however, no nuclear model is found to be complete. The quality of predictive nuclear models are often assessed by comparing the theoretical electromagnetic transition rates with the experimental measurements. An accurate transition rate measurement for excited nuclear states allows the determination of their corresponding off-diagonal matrix elements, and thus the study of their nuclear wavefunctions using well-defined electromagnetic multipole operators.

To contribute to these measures, a low-energy Coulomb excitation experiment was performed at TRIUMF to measure transition rates in $^{36}$Ar, by delivering an $^{36}$Ar beam to a natural carbon target with $^{197}$Au backing. The TRIUMF-ISAC Gamma-Ray Escape Suppressed Spectrometer (TIGRESS) and the TIGRESS Integrated Plunger (TIP) devices, developed by Simon Fraser University (SFU), were used for $\gamma$-ray and charged particle detection, respectively. The experimental data indicated a formation of excited $^{37}$Ar due to a probable neutron transfer process from $^{13}$C to $^{36}$Ar. In total, four states, $3/2^{-}_{2}$, $3/2^{-}_{1}$, $7/2^{-}_{1}$ and $1/2^{-}_{1}$, were observed to be populated in $^{37}$Ar. Although studies of $^{37}$Ar have been conducted previously, the availability of the data opens an opportunity for high precision transition rate measurements in $^{37}$Ar.

The transition rate measurements of the observed states in $^{36}$Ar and $^{37}$Ar have been completed with the Doppler-Shift Attenuation Method (DSAM) and the Delayed Coincidence Method (DCM). Results of transition rate measurements for both nuclei will be presented and discussed, with a focus on the analysis of $^{37}$Ar with a newly developed GEANT4 reaction model based on Rutherford scattering and neutron transfer through quantum tunnelling. This analysis is part of an ongoing collaboration with theoretical physicists, and the findings will be presented and discussed.

Speaker: Hon Pan Tam (SFU Physics)

25 Position Sensitive Organic Glass Scintillator Bars for Neutron Time of Flight Spectroscopy

Neutron time of flight spectroscopy is a valuable tool for a wide range of nuclear physics experiments. These include direct measurements of astrophysical ($\alpha$,n) or (p,n) reactions; nuclear spectroscopy through transfer reactions such as (d,n); and decay spectroscopy of neutron-unbound states. Such experiments require fast neutron detectors with high detection efficiency, sub-ns timing resolution, and position sensitivity on the order of a few centimetres. In many cases, neutron/$\gamma$-ray discrimination capabilities are also required to eliminate prompt and random $\gamma$-ray backgrounds.

Recently, a new scintillaor material, composed of an organic glass (organic glass scintillator, OGS) has been exploited for neutron detection. This material has good efficiency for detecting ${\gtrsim} 1$ MeV neutrons, fast timing capabilities, and excellent $n/\gamma$ pulse shape discrimination properties. As a glass, the material can be cast in a mold, allowing a wide range of detector geometries. This talk reports our recent efforts to characterize extended $1^{\prime\prime} \times 1^{\prime\prime} \times 5^{\prime\prime}$ bars of OGS, read out by a photo-multiplier tube on either end. The talk focuses on bench-top measurements with $\gamma$-ray and neutron sources characterizing the detector's energy resolution, position sensitivity, timing resolution, and $n/\gamma$ separation capabilities. Possible applications of these bars to future nuclear physics measurements will also be discussed.

Speaker: Prof. Greg Christian (Saint Mary's University)

26 Development of statistical tools for studies of the rapid neutron capture process

The rapid neutron capture process (r-process) is believed to be responsible for the synthesis of the heaviest elements in the Universe and to occur in extreme astrophysical events such as compact binary mergers. Despite a multitude of efforts and developments to understand the workings of the r-process both in nuclear physics and astrophysics, many challenges and unknowns remain. One of such challenges is to quantitatively gauge our understanding of the r-process, in other words, to obtain comprehensive uncertainty estimates in the theoretical reproduction of observable quantities.

Theoretical calculations of r-process observables are known to be sensitive to the choice of nuclear physics inputs, such as mass model, beta-decay rates, neutron capture rates, fission properties, and more. Quantification and incorporation of the uncertainty of nuclear physics inputs in the r-process calculations is still a topic of active investigation. In this talk, applications of several statistical techniques to handle the uncertainty of nuclear physics inputs in the r-process studies will be discussed. Recent developments and applications of nuclear data based on nuclear density functional theory will also be touched upon.

Speaker: Mr Yukiya Saito

(DTP) M1-7 Quantum Systems I | Systèmes quantiques I (DPT)

27 Quantum catastrophes

Caustics are singularities arising from wave focusing. Examples include rainbows, gravitational lensing, and freak waves. The natural mathematical language for describing caustics is catastrophe theory which predicts that caustics take on certain universal shapes. When applied to classical waves one finds that the singularities seen at large scales are replaced at short scales by smooth universal interference patterns that obey a remarkable set of scaling relations. My group has been extending these ideas to quantum fields such as those that occur in spin chains, Bose-Einstein condensates, and in waves near event horizons. While in some cases we get discretised versions of the classical wave catastrophes, we also find new types of catastrophe associated with particle production.

Speaker: Dr Duncan O'Dell (McMaster University)

28 Ultrastrong coupling, nonselective measurement and quantum Zeno dynamics

We study the dynamics of an open quantum system linearly coupled to a bosonic reservoir. We show that, in the ultrastrong coupling limit, the system undergoes a nonselective measurement and then evolves unitarily according to an effective Zeno Hamiltonian. This dynamical process is largely independent of the reservoir state. We examine the entanglement breaking effect of the ultrastrong coupling on the system. We also derive the evolution equation for systems in contact with several reservoirs when one coupling is ultrastrong. The effective system dynamics displays a rich structure and, contrarily to the single reservoir case, it is generally non-Markovian. Our approach is based on a Dyson series expansion, in which we can take the ultrastrong limit termwise, and a subsequent resummation of the series. Our derivation is mathematically rigorous and uncomplicated.

Speaker: Marco Merkli

29 Form-preserving transformations of wave and Wigner functions

Solutions of the time-dependent Schrödinger equation are mapped to other solutions for a (possibly) different potential by so-called form-preserving transformations. These time-dependent transformations of the space and time coordinates can produce remarkable solutions with surprising properties. A classic example is the force-free accelerating Airy beam found by Berry and Balazs. We review the 1-dimensional form-preserving transformations and show that they also yield Senitzky coherent excited states and the free dispersion of any waveform. Form preservation of the $D$- and 3-dimensional Schrödinger equation with both a scalar and a vector potential is then considered. It is shown that time-dependent rotations may be included when a vector potential is present. Moving to phase space, we consider the rigid translations that characterize the Airy beam and the coherent excited states. Then we study form-preserving transformations of the quantum Moyal equation obeyed by Wigner functions. The explicit transformation formula is the natural analog of the simple transformation of classical phase-space densities. It explains and generalizes the above-mentioned rigid translation in phase space.

Speaker: Prof. Mark Walton (University of Lethbridge)

(PPD) M1-8 Neutrino telescopes | Télescopes à neutrinos (PPD)

30 Exploring the Universe from Deep Below the Waves: The Pacific Ocean Neutrino Experiment

The Pacific Ocean Neutrino Experiment (P-ONE) is a planned multi-cubic-kilometer neutrino telescope in the Northeast Pacific Ocean off Vancouver Island, British Columbia. Its primary goal is to detect high-energy neutrinos, offering key insights into cosmic ray origins and acceleration mechanisms. Building on two successful pathfinder missions, the collaboration, in partnership with Ocean Networks Canada (ONC), is preparing to deploy its first detector line, P-ONE-1. This initial deployment will consist of 20 optical and calibration modules integrated into a novel hybrid cable architecture spanning over 1000 meters, connected to ONC’s NEPTUNE deep-sea observatory. The extreme ocean environment, dynamic conditions, and background noise from bioluminescence and K-40 decay present unique challenges, requiring innovative design solutions while ensuring modularity and scalability. This talk will present an overview of P-ONE and highlight ongoing development and simulation efforts for P-ONE-1.

Speaker: Patrick Krause (SFU)

31 The Icecube neutrino observatory: status and recent results

The IceCube neutrino observatory is a Cherenkov light detector in the Antarctic ice sheet, at the South Pole. Composed of a cubic kilometer of detector volume instrumented with over 5000 photo-multiplier tubes, it is the largest neutrino detector in the world, observing neutrinos incident from all directions. Having collected data for 13 years in its current configuration, the IceCube experiment has achieved notable results such as the identification of neutrino sources including the Milky Way and active galaxy NGC 1068, and observation of the Glashow resonance. A more densely instrumented infill (DeepCore) has allowed the experiment to achieve world-leading precision measurements of atmospheric neutrino oscillation parameters. In this talk, a summary of the current status of IceCube and key recent results is presented, as well as an overview of ongoing upgrades to the detector to enhance the neutrino oscillation physics potential of the experiment.

Speaker: Daniel Durnford (University of Alberta)

32 Electron Neutrino Tagging in IceCube Using Graph Neural Networks

The IceCube Neutrino Observatory detects Cherenkov light from neutrino interactions in the Antarctic ice. Despite more than a decade of operation, distinguishing electromagnetic and hadronic showers remains a persistent challenge. Accurately identifying electromagnetic showers provides a charged-current electron-neutrino-rich sample, which plays a pivotal role in Neutrino Mass Ordering studies. To address this challenge, we use the upcoming IceCube Upgrade (2025/26) and Graph Neural Networks (GNNs). The Upgrade, featuring advanced sensors and seven additional strings in the densely instrumented central region, enhances GeV-scale neutrino detection. GNNs, which effectively handle the irregular detector geometry, enable improved shower classification. Several parameters for identifying electromagnetic showers are explored in the Upgrade simulation dataset. Our recent studies demonstrate, for the first time, a clear separation between electromagnetic and hadronic showers.

Speaker: Akanksha Katil (University of Alberta)

33 The P-ONE Slow Control Framework

The P-ONE neutrino observatory is a proposed water Cherenkov detector for the study of astrophysical neutrinos in the TeV-PeV energy range. Upon completion the detector will contain tens of thousands of photo-multiplier tubes in a cubic-kilometer array located on the seafloor at Cascadia basin, just off the shore of Vancouver Island. To accurately reconstruct the type, energy, and direction of an incident neutrino event we must have precise knowledge of PMT positions, water properties, detector efficiencies, and other metrics. To this end, an additional sum of nearly twenty thousand calibration and monitoring sensors will be placed alongside our PMTs to give real time information on the detector status. Processing of this “slow” data and control of the detector will be achieved through the Maximum Integrated Data Acquisition System (MIDAS) created by TRIUMF. This talk will highlight the current state of both hardware and software for the P-ONE slow control framework.

Speaker: Nathan Molberg

34 SiPM optical modeling and optical crosstalk simulation for ARGO

ARGO is a future dark matter direct-detection experiment based on a liquid argon (LAr) target that is proposed to be built at SNOLAB in the next decade. ARGO will produce leading sensitivity to heavy dark matter searches above 50 GeV/c2. It will also have excellent sensitivity to detect core-collapse supernova neutrinos and produce high-precision measurements of solar neutrinos at and above the 7Be shoulder. For photodetection in ARGO, we are interested in pixelated silicon photomultiplier (SiPM) photosensors with fast photon timing that will allow good position reconstruction and novel hit-pattern-based event discrimination. However, the optical crosstalk (oCT) noise associated with SiPMs can affect the electronic recoil/nuclear recoil pulse-shape discrimination and distort spatial/temporal photon hit patterns, limiting background rejection. We have developed a full Monte Carlo simulation of a pixelated SiPM system including oCT to evaluate the detector performance and to determine constraints on SiPMs to reach that performance. In my talk, I will describe our MC model and present some results about the impact of oCT on the detector energy threshold and the event position reconstruction.

Speaker: Dr Asish Moharana (Carleton University)

(DPMB) M1-9 | (DPMB): Emerging Order: Probing Nature Through Light, Motion, and Memory

35 Classification of Retinal TDP-43 and Amyloid beta Deposits as Biomarkers of Differing Neurodegenerative Diseases

Introduction: We have used polarized light to image and differentiate protein deposits as biomarkers of different neurodegenerative diseases and their severity; including amyloid deposits in Alzheimer’s disease (AD) and alpha synuclein deposits found in other brain diseases. Here we differentiate, with polarized light, retinal deposits of amyloid beta, associated with AD, from TDP-43 deposits found in the neurodegenerative diseases Frontotemporal Lobular Dementia (FTLD) and Amyotrophic Lateral Sclerosis (ALS). Our retinal imaging could be the first differential diagnostic of neurodegenerative diseases.
Methods: Post-mortem eyes and brains were obtained from 2 individuals with ALS, including 1 who also had FTLD, and 4 individuals with only FTLD, including 1 with Type C. Brain TDP-43 was present, except in the ALS case and some had brain age-related tau. 10 individuals had brain amyloid beta and tau and a moderate to high likelihood of AD. Flat-mounted retinas were imaged using a polarimeter. Polarimetric properties of deposits were analyzed for 270 presumed amyloid beta deposits in those with AD, and 138 presumed TDP-43 deposits in those with FTLD and/or ALS. In 1 case of ALS with concurrent low values of brain amyloid and 1 of FTLD-Type C, only thioflavin negative deposits were classed as potential TDP-43 deposits. Random forest, an ensemble learning method, was then used to differentiate amyloid beta from TDP-43 deposits.
Results: Thioflavin positive deposits in the retina with FTLD type C had interactions not different from AD deposits, consistent with a recent report of protein fibrils which combine TDP-43 and the amyloid protein ANXA11. The deposit means and/or standard deviations of nine different polarized light interactions were significantly different between the other TDP-43 retinal deposits, found in ALS and FTLD, and amyloid deposits found in AD. We achieved a classification accuracy of 83.9± 0.5% using random forest and utilizing only 6 of these interactions.
Conclusions: Polarized light imaging can differentiate retinal deposits associated with Alzheimer’s disease from those linked to ALS and FTLD, with a relatively high accuracy. This first differential diagnostic of Alzheimer's disease from TDP-43 related diseases, is early, non-invasive and inexpensive and would reach underserved populations.

Speaker: Lyndsy Acheson (University of Waterloo)

36 Computational Analysis of Dioxin-Like Compounds: Investigating Interactions with AhR and Cytochrome P450 Enzymes

Dioxin-like compounds (DLCs) are environmental pollutants known for their high toxicity and persistence, primarily exerting their effects through interactions with the aryl hydrocarbon receptor (AhR) and subsequent metabolic processing by cytochrome P450 enzymes. To elucidate the molecular mechanisms underlying these interactions, we employed first-principle computational methods, including density functional theory (DFT) and molecular dynamics (MD) simulations.

Our study focused on analyzing key parameters such as Root Mean Square Deviation (RMSD), Root Mean Square Fluctuation (RMSF), and Solvent Accessible Surface Area (SASA) to assess the conformational stability and dynamics of ligand-AhR complexes. The binding affinities and interaction profiles of various DLCs with AhR were evaluated to identify potential high-affinity ligands.

Furthermore, we investigated the interactions between these ligands and cytochrome P450 enzymes during the metabolic process. By simulating the metabolic pathways, we aimed to predict the biotransformation products and assess their potential toxicities.

Our findings provide insights into the structural and dynamic aspects of DLC interactions with AhR and P450 enzymes, contributing to a better understanding of their toxicological profiles. This computational approach offers a valuable framework for predicting the behavior of environmental toxins and aids in the development of strategies for risk assessment and mitigation.

Speaker: Mr Ali Abdolahzadeh Ziabari (Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, SK S7N 5E2)

37 Measuring Photosynthetic Health Through Delayed Fluorescence: a New Device and Biometric for Environmental Health

Photosynthetic organisms exhibit delayed fluorescence (DF) emissions related to chlorophyll in their photosystem II complex. These emissions are weak, accounting for only 0.03% of the total fluorescence emission, and can only be found in healthy, photosynthetically-active cells in living systems. Emission lifetimes, if detected with high sensitivity, can be used as a non-invasive biomarker of an organism's health. To the best of our knowledge, while DF emissions have been studied previously in phytoplankton species, no investigations have been conducted on algal organisms that also exhibit bioluminescence. The Dinoflagellate species Pyrocystis fusiformis is a marine alga that bioluminesces in response to mechanical shear stress exerted on its cell membrane. We have developed a novel silicon photo-multiplier (SiPM) Geiger-mode photon-counting technology to characterize time-resolved DF behaviour in P. fusiformis. Here we shall discuss advancements made in our new photon-counting instrument and integration of a cooling chamber to improve the low signal to noise ratio to sensitively capture bioluminescence and DF for comparison across various environmental stressors such as methane, CO$_2$ and phosphorus. With the development of this low-cost, portable photon-counting device, we plan to study the impact of these environmental stressors on DF emissions of P. fusiformis in support of our overarching goal of examining indicators of photosynthetic environmental health in aquatic ecosystems.

Speaker: Elizabeth Allison (York University)

38 Avalanche dynamics in a 2D tumbling drum with frictionless, cohesive oil droplets

The macroscopic behaviours of granular materials are heavily dependent on their microscopic interactions. We explore the dynamics of microscopic frictionless oil droplets with a well controlled cohesive interaction in a 2D tumbling drum. The disordered, bidisperse aggregate of droplets rearrange in the rotating drum quasi-statically. We observe the angle at which the granular aggregate begins to flow, and the angle to which the system settles, post-avalanche. We explore buoyancy force to contrast the response of poly-crystalline and disordered aggregates, as well as the effect of the strength of cohesion between droplets.

Speaker: Simaya Rosenbloom (McMaster University)

39 Photon-to-Digital Converters – 3D Integrated Digital Single-Photon Detector Arrays Enabling Time-of-Flight PET and CT

We develop 3D integrated Photon-to-Digital Converters (PDC) for photon counting applications needing sub-nanosecond timing resolution. Our goal is to provide a detector capable of delivering single photon timing resolution below 50 ps that could enable Time-of-Flight positron emission tomography (ToF-PET) and computed tomography (ToF-CT). We will review the benefits and the challenges posed by these ToF modalities.
In previous years we reported on various TSMC 65nm CMOS readouts embedding Time-to-Digital Converters (TDC) and processing electronics optimized for time-of-flight applications. We will report on the performances of our multi-vernier TDCs and their integration in a readout array, particularly the need for calibration and strategies to do so.
We will also report on the design of a $5\times 5~\text{mm}^2$ readout ASIC being designed for ToF-PET and ToF-CT, and on the production schedule.

Speaker: Prof. Serge Charlebois (Université de Sherbrooke)

40 Accuracy of Hyperspectral Near-Infrared Spectroscopy in Measuring Tissue Water Content

Introduction: Edema, an abnormal increase in tissue water fraction (WF), affects over one million Canadians chronically. Cerebral edema (CE) is especially concerning, as it is a predictor of mortality in stroke and traumatic brain injury. While magnetic resonance imaging and computed tomography can assess WF, they are costly, not readily available, and inappropriate for continuous monitoring. Hyperspectral near-infrared spectroscopy (h-NIRS) offers a frugal alternative, using light attenuation across many wavelengths to quantify tissue components like water. This study evaluates the accuracy of h-NIRS for WF estimation using simulations and tissue-mimicking phantoms.
Methods: Simulations were run in NIRFAST v9.1 with source-detector separations of 10‒40 mm. Two sets of simulation were conducted: one incorporating only tissue-like scattering and water, and another also included oxy- and deoxy-hemoglobin (tissue oxygen saturation of 65%). In both cases, WF ranged from 50% to 90%. Two corresponding sets of tissue-mimicking phantom experiments were conducted using gelatin, distilled water and a constant concentration of Intralipid-20% as the scattering agent. The first set included only scattering and water, with WF from 50–90% in 10% steps. The second added India Ink (1 mL of a solution diluted to 0.05–0.25% in 0.05% increments) to simulate absorption, testing WF at 50%, 70%, and 90%. A 20-W halogen lamp and QE-Pro spectrometer were used for measurements. Measurements were acquired using a 20-W halogen lamp and QE-Pro spectrometer. Light was delivered and collected via optical fiber bundles placed on the phantom surface at the same source-detector separations used in the simulations. WF was estimated using a spatially resolved approach. Accuracy was assessed via root-mean-square error (Arms) and variability via coefficients of variation (CoV).
Results: Simulations and phantoms experiments showed high accuracy, with Arms< 2.5%. Slight increases in error were observed with the inclusion of hemoglobin/India Ink. CoV remained below 6% across phantom tests, indicating strong reproducibility.
Discussion: The h-NIRS technique demonstrated excellent accuracy and repeatability under all tested conditions. Limitations include the use of homogeneous phantoms and India Ink rather than blood. Future work will incorporate whole animal blood to better simulate tissue absorption.

Speaker: Dr Mamadou Diop (Western University & The Lawson Health Research Institute)

41 Design of Gradient Coil Geometry for a Halbach-Based Ultra Low-Field MRI System

Introduction: Magnetic Resonance Imaging (MRI) is a powerful diagnostic tool that provides detailed images of soft tissues, making it essential for a wide range of medical applications. However, conventional MRI systems rely on high-field (1.5 – 3.0 Tesla [1, 2]) superconducting magnets, resulting in high cost [3, 4], significant infrastructure requirements, and limited accessibility in many healthcare settings. Ultra-low-field (ULF) MRI systems operate below 0.1 Tesla [5, 6], and introduce an alternative approach, leveraging permanent magnet arrays and modern image-processing techniques to achieve clinically relevant imaging at a fraction of the cost. This research project focuses on the design, simulation, and evaluation of gradient coils optimized for a Halbach-based ULF MRI system. The magnetic field in a Halbach array is oriented perpendicular to the bore, requiring gradient coils that can operate effectively in this non-traditional geometry.
Methods: By integrating coil design methodologies such as the target field and stream function method [7, 8], and numerical simulations done within COMSOL Multiphysics, this project aims to identify the feasibility of a Halbach-based ultra-low-field system and enhance image quality and system performance by designing and developing physically realizable coil windings and custom geometries for x- and y-gradient coils. Simulation studies were conducted in COMSOL Multiphysics to evaluate magnetic field linearity and generate profiles of the x and y direction gradients.
Results: Gradient linearity was quantitatively assessed by comparing simulated magnetic field profiles using a percentage difference calculation over ideal linear gradients. Results showed gradient linearity values of 2.41% and 0.89% for the x- and y-gradient coil geometries, respectively, indicating strong encoding fidelity and minimal distortion over a 20-centimeter imaging region.
Discussion: We show an effective design for a ULF MRI. Further studies include expanded parameters in the simulations, such as differing wiring materials, time dependence, and thermal performance of the gradient coils.

[1] M. Sarracanie, C. D. LaPierre, N. Salameh, D. E. J. Waddington, T. Witzel, and M. S. Rosen, Sci Rep, vol. 5, no. 1, p. 15177 (2015)
[2] C. D. E. Van Speybroeck, T. O’Reilly, W. Teeuwisse, P. M. Arnold, and A. G. Webb, Physica Medica, vol. 84, pp. 116–124 (2021)
[3] S. Huang, Z. H. Ren, S. Obruchkov, Ji. Gong, R. Dykstra, and W. Yu, Investig Magn Reson Imaging, vol. 23, p. 179 (2019)
[4] M. Sarracanie, C. D. LaPierre, N. Salameh, D. E. J. Waddington, T. Witzel, and M. S. Rosen, Sci Rep, vol. 5, p. 15177 (2015)
[5] B. De Vos et al., Front. Phys., vol. 9, p. 701157, (2021)
[6] C. D. E. Van Speybroeck, T. O’Reilly, W. Teeuwisse, P. M. Arnold, and A. G. Webb, Physica Medica, vol. 84, pp. 116–124 (2021)
[7] R. Turner, J. Phys. D: Appl. Phys., vol. 19, no. 8, pp. L147–L151 (1986)
[8] D. Tomasi, Magn. Reson. Med., vol. 45, no. 3, pp. 505–512 (2001)

Speaker: Jacob Beaudoin (Dept. of Biomedical Engineering, University of Calgary)

42 A Fast Method for Mapping pH using Magnetic Resonance Imaging

Introduction: Magnetization Transfer (MT) is a Magnetic Resonance Imaging (MRI) contrast enhancement technique that exploits the exchange of magnetization between pools of free-water protons and protons bound to macromolecules in tissue [1]. Chemical Exchange Saturation Transfer (CEST) MRI is a direct application of MT, which can noninvasively image dilute CEST agents (including amide molecules), enabling the assessment of tissue characteristics, such as pH [2-4]. Detection of pH variations in the brain has been shown to be valuable for delineation of tissue-at-risk compared to tissue with reduced cerebral blood flow, following an acute ischemic stroke [5-7]. This work aims to create a CEST based pH mapping acquisition that is fast (<5min) and is able to cover the entire brain with high resolution (<2mm), for the identification of ischemic tissue-at-risk.

Methods: Our method employs a basic 3D gradient recalled echo as a foundation for the CEST pulse sequence. The custom CEST technique utilizes 30 offset radio-frequency preparation pulses to effectively saturate amide molecules required for pH mapping. Image acceleration has been implemented through 4D-Poisson distributed under-sampling in concert with compressed sensing [8]. Our lab has previously demonstrated quantitative MT image acceleration with up to 4x acceleration, and has shown that 8-12x times may be achievable for CEST imaging [9].

Results: When implemented on the GE 3T scanner, the CEST pulse sequence will achieve an accelerated image acquisition with minimal artefacts compared to the fully sampled images. This will be accomplished with a large FOV (22 cm x 14 cm x 16 cm) and isotropic 2 mm resolution. Accelerated imaging for both 3D, and ultimately 4D, is expected to execute in 5 minutes or less for a total of 30 volumes.

Discussion and Future Work: We have designed a pH mapping sequence for ischemic stroke that is fast and high resolution. Next steps include validation on a phantom with varying pH from 5.8 to 7.0. In-vivo validation will be achieved via scanning of approximately 10 patients with cerebral ischemia.

[1] R. S. Balaban and T. L. Ceckler, 8(2):116–37 (1992)
[2] Z. Dai et al., PLoS ONE, 9(11):e112219–e112219 (2014)
[3] van Zijl PCM, Lam WW, Xu J, Knutsson L, Stanisz GJ. NeuroImage, 168:222-241 (2018)
[4]. Villano D, Romdhane F, Irrera P, et al. Magnetic Resonance in Medicine, 85(3):1335-1349 (2020)
[5] Ding Y, Rastogi R, Xia S, et al. Brain Circulation, 1(1):26 (2015)
[6] Foo LS, Harston G, Mehndiratta A, et al. Quantitative Imaging in Medicine and Surgery, 11(8):3797-3811 (2021)
[7] Frullano L, Catana C, Benner T, Sherry AD, Caravan P. Angewandte Chemie, 122(13):2432-2434 (2010)
[8] M. Lustig, D. Donoho, and J. M. Pauly, Magnetic Resonance in Medicine, 58(6):1182–1195 (2007)
[9] McLean M, Lebel R M, MacDonald M E, et al. 1-4 (2019)

Speaker: Nicole Lofroth (Dept. of Biomedical Engineering & Hotchkiss Brain Institute, University of Calgary)

12:00 Break for Lunch (12h00-13h30) | Pause pour dîner (12h00-13h30)

Canadian Science Publishing - Publishing Process and Peer Review | Processus de publication et examen par les pairs

43 Publishing Processes and Peer Review | Processus de publication et examen par les pairs

Join the Canadian Journal of Physics for a structured discussion on the publishing industry and the processes and roles involved in a manuscript’s publication. From authorship and submission to author rights and protections post-publication, we’ll discuss how your research is assessed and handled in physics journals across publishers. Best practices for peer review, as an author or a reviewer, will also be presented.

We welcome physicists from all career stages to ask questions, reflect on their publishing experiences, and learn something new! The discussion will be hosted by Journal Development Specialist Jocelyn Sinclair, and Editors-in-Chief of CJP Prof. Marco Merkli (Memorial University of Newfoundland) and Dr. Zahra Yamani (Canadian Nuclear Laboratories).

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Résumé : Rejoignez le Journal canadien de physique pour une discussion structurée sur l’industrie de l’édition et les processus et rôles impliqués dans la publication d’un manuscrit. De la paternité et de la soumission aux droits d’auteur et aux protections après publication, nous discuterons de la façon dont votre recherche est évaluée et traitée dans les revues de physique de tous les éditeurs. Les meilleures pratiques en matière d’évaluation par les pairs, en tant qu’auteur ou évaluateur, seront également présentées.

Nous invitons les physiciens à tous les stades de leur carrière à poser des questions, à réfléchir sur leurs expériences en matière de publication et à apprendre quelque chose de nouveau ! La discussion sera animée par Jocelyn Sinclair, spécialiste du développement des revues, et par les rédacteurs en chef de CJP, le professeur Marco Merkli (Memorial University of Newfoundland) et le docteur Zahra Yamani (Laboratoires nucléaires canadiens).

Speakers: Jocelyn Sinclair (Canadian Science Publishing), Marco Merkli (Memorial University of Newfoundland), Zahra Yamani (Canadian Nuclear Laboratories)

High School / Cégep Teachers' Day Lunch | Déjeuner de la journée des enseignants de l'école secondaire / du cégep

Student Networking Session (SAC) | Session de réseautage pour les étudiant(e)s (CAE)

High School / Cégep Teachers' Day P.M. Workshop Sessions

13:00 Panel: Supporting student success in physics

14:00 Physics Teaching and Learning Topic Tables

M-PLEN2 Herzberg Medal Plenary Session | Session plénière - Jo Bovy, U. Toronto

44 The small-scale structure of dark-matter halos

Much about dark matter remains unknown and much can be learned about its nature from its distribution on sub-galactic scales. I will discuss measurements of the small-scale structure of dark matter in elliptical galaxies and in the Milky Way from gravitational lensing and stellar streams and how these measurements constrain various interesting dark matter models in a complementary manner. I will conclude by looking forward to the data-rich future ahead in the next decade, which will let us answer the fundamental question: Is dark matter cold?

Speaker: Jo Bovy

14:00 Travel Time | Durée du voyage

(DAPI) M2-1 | (DPAI) Accelerator Topics

45 CERN at 70 at the Crossroads: Future Directions for Particle Physics

Accelerator based particle physics has delivered an amazing scientific success story, lead in part over the last 70 years by CERN. In 2025, there will be an update to the European Strategy on Particle Physics which will set the direction for what will come after the High Luminosity LHC upgrade, that is scheduled to extend operations until 2042. This talk will give an overview of the past successes, physics questions beyond the standard model, future challenges and a glimpse at some of the future directions for CERN.

Speaker: Eliezer Rabinovici (Weizmann Institute of Science (IL))

46 TRIUMF - Canada's particle accelerator laboratory

Established in 1968 in Vancouver, TRIUMF is Canada’s particle accelerator centre. The lab is a hub for discovery and innovation in answering nature’s most challenging questions. From the hunt for the smallest particles in our universe to research that advances the next generation of batteries or develops isotopes to diagnose and treat disease. The research is powered by TRIUMF's complex accelerator complex that allows pushing the frontiers in isotope science and innovation, as well as technologies to address fundamental and applied problems in particle and nuclear physics, and the materials and life sciences. An actual overview and outlook to the completion of the Advanced Rare Isotope Laboratory (ARIEL) will be provided.

Speaker: Prof. Oliver Kester (TRIUMF)

47 Canada's involvement in the Electron Ion Collider

The Electron-Ion Collider (EIC) is a new particle collider facility to be built in the US with significant participation of the EIC Canada Collaboration. At the EIC, polarized electrons will collide with polarized protons or ions to answer questions about the origin of mass and spin of protons. The EIC Canada Collaboration will provide two pieces of key infrastructure for the EIC and its primary detector.
On the accelerator side we will build the 394 MHz Superconducting Radiofrequency crab cavities that will increase ten-fold the probability of collisions necessary for scientific discovery. The construction of these crab cavities will cement Canada's position at the forefront of superconducting radiofrequency technology. Aside from providing critical training for Canadian scientists and engineers, superconducting accelerator technology reduces the size of medical accelerators for cancer therapy and isotope production.

Speaker: Robert Laxdal

48 The New Infrared Free Electron Laser at Waterloo: Progress and Future Applications

Canada’s new infrared free electron laser (IR-FEL) user facility will be built at the University of Waterloo. This initiative, which is being undertaken in partnership with TRIUMF, the Canadian Light Source, and several universities from across Canada, will open new research directions in health sciences, the natural sciences, and engineering. Based on the successful designs of the IR-FELs at FELIX and the Fritz Haber Institute, WaterFEL will enable characterization of molecules and materials, with applications in food safety and security, environmental monitoring, and diagnosis of disease. This seminar will provide an overview of infrastructure specifications, timelines, and future research directions.

Speaker: Scott Hopkins (University of Waterloo)

(DTP) M2-10 Quantum Systems II / Astrophysics of Compact Objects | Astrophysique des objets compacts (DPT)

49 Non-Markovianity and entanglement in collision models with initial intra-environment correlations

Collision models (CMs) describe quantum systems interacting sequentially with elements of an environment, termed ancillas. These simple models are valuable for analyzing non-Markovian quantum dynamics by controlling environmental memory through feedback mechanisms. Their simplicity and versatility have led to applications in quantum optics, quantum information, and quantum thermodynamics.
In this work, we investigate how ancilla-ancilla entanglement relates to memory effects in the system dynamics. We first discuss how the non-Markovian system can be mapped to a larger, Markovian system (Markovian embedding). We then apply this framework to an all-qubit CM and compare the non-Markovianity of the system alone when the ancillas are correlated in two ways: after or before the collision with the system. In the former case the dynamics is always Markovian, but in the latter case non-Markovianity is produced - however, maximal initial entanglement between the incoming ancillas suppresses that non-Markovianity.

Speaker: Angel Neira (Memorial University of Newfoundland)

50 Simulating a superposition of spacetimes with optical media

Under certain conditions, an arbitrary spacetime can be modelled as an equivalent optical medium characterized by properties such as permittivity, which modifies the speed of light propagation and, consequently, the structure of light cones. To explore quantum effects in this context, we investigate the evolution of a single electromagnetic field mode in a cavity where the permittivity depends on the state of a control qubit, creating a superposition of permittivities.
By measuring the control qubit along a superposition basis rather than tracing over its Hilbert space, we imprint the effects of the superposition on the electromagnetic field mode. We derive an analytical expression for the probability of measuring the control qubit in a superposition state as a function of two constant permittivities, revealing how a quantum superposition of optical properties affects the electromagnetic field mode dynamics.
By showing how a superposition of permittivities influences field dynamics, this work represents an early step toward simulating a quantum superposition of spacetimes in the lab using optical media.

Speaker: María Rosa Preciado-Rivas (University of Waterloo)

51 Unravelling the mysteries of black holes and neutron stars with flashes, bursts and eruptions

The most powerful cosmic engines in our universe are fueled by compact objects such as black holes and neutron stars. These cosmic engines consume large amounts of material and expel matter in the form of jets travelling at near the speed of light. Recent groundbreaking discoveries of gravitational waves from systems harbouring compact objects and the direct imaging of the black hole shadows with the Event Horizon Telescope, represent major steps forward in our understanding of such systems. However, there exists a huge population of compact objects in our own Galaxy which provides much more ideal laboratories, offering a real-time view of the behaviour of these compact objects and their dynamic environments. In this talk, I will discuss new experiments leveraging the capabilities of today's state-of-the-art telescopes to observe repetitive, (somewhat) predictable, energetic surges of radiation that allow us to track the path of material from inflow to outflow in these Galactic systems.

Speaker: Alexandra Tetarenko (University of Lethbridge)

52 Compact Stars and Extreme Compact Objects (ECOs) in 4D Einstein Gauss-Bonnet Gravity

Since the derivation of a well-defined D→4 limit for 4D Einstein-Gauss-Bonnet (4DEGB) gravity coupled to a scalar field, there has been considerable interest in testing it as an alternative to Einstein's general theory of relativity. This theory hosts interesting compact star solutions which can be smaller in radius than a Schwarzschild black hole of the same mass in general relativity (GR). We solve the field equations for such objects described by a variety of neutron/quark equations of state (EOSs) and discuss the way such the resultant mass-radius curves interact with the black hole solutions and modified Buchdahl bounds of the 4DEGB theory. For a number of the considered cases the stability under radial perturbations is also studied and we find that the stability criterion from GR (\partial M/\partial \rho_c > 0) still applies in the modified theory of gravity. With this, many of the unusual ECO solutions are indeed stable, as well as a host of solutions which overlap with recent unexplained observations of compact objects.

Speaker: Michael Gammon (University of Waterloo)

53 Resolving a Cosmological Tension with Galaxy Cluster Formation Histories

Our concordance cosmological model describes the history and large-scale structure of the universe using a few key parameters, one of which is the clustering of matter due to density fluctuations in the early universe. Modern constraints on this parameter using different observational methods are in statistical tension. Our ability to resolve this tension is limited by the parameter’s degeneracy with the overall matter density when inferred from observations of galaxy clusters. An improved understanding of galaxy cluster formation history can break the degeneracy, providing new insights into this tension in our cosmological model. Using the IllustrisTNG suite of cosmological simulations, we explore structural indicators of the dynamical state of galaxy clusters and their correlations with mass accretion history and formation time. We find that large centre-of-mass offsets, luminosity gaps, and asymmetries in galaxy clusters consistently identify dynamically disturbed systems that have undergone recent major mergers. These structural properties of galaxy clusters observable through x-ray emission, weak gravitational lensing, and intra-cluster light may greatly improve the constraining power of galaxy cluster samples in large forthcoming surveys. By identifying indicators of the dynamical states of galaxy clusters and their relationships to growth history, this work will provide insight into galaxy evolution in different environments, cluster mergers, and the ongoing tension in cosmological parameter constraints.

Speaker: Rashaad Reid (University of Waterloo)

(DASP) M2-2 General Topics: Planetary Physics and Astronomy | Thèmes généraux: Physique planétaire et astronomie (DPAE)

54 A Virtual Solar Wind Monitor at Mars to Enable Statistical and Comparative Magnetospheric Studies

Unlike Earth, Mars does not possess an upstream solar wind monitor. This lack of continuous solar wind observations has fundamentally limited scientific studies that investigate solar wind impacts on the Mars space environment. This lack of a dedicated upstream monitor has also limited emerging operational tasks for predicting space weather throughout our solar system. Previous estimates of the solar wind have been pursued through physics-based modeling efforts (e.g. magnetohydrodynamic models) or empirical (e.g. assuming statistical relationships with downstream observations) proxies. Proxies are often based on downstream observations from multiple orbiting spacecraft. These spacecraft pass in and out of the bow shock providing a semi-regularly sampling of the pristine solar wind. The most complete, and ongoing, set of the solar wind’s magnetic field and plasma parameters is from the NASA MAVEN spacecraft. MAVEN has orbited Mars since 2014, but additional assets add resolution to this dataset such as including ESA’s MEX mission which has been in orbit since 2003, and the CNSA’s Tianwen-1 orbiter since 2021.

In this presentation I will discuss the creation of a first continuous solar wind estimation upstream from Mars. This virtual solar wind monitor, or vSWIM (see Azari et al., 2024, doi: 10.1029/2024JH000155) was trained and assessed on MAVEN data. vSWIM is generated from Gaussian process regression, a type of machine learning, and is used to provide predictions, and uncertainties on these predictions, at various temporal resolutions. This has enabled subsequent statistical studies, including for understanding the causation of sinuous aurora - a unique Martian aurora. I will conclude with a discussion of scientific studies enabled by vSWIM, including comparative magnetospheric studies, and provide an outlook for vSWIM’s multi-spacecraft integration for operational space weather prediction efforts.

Speaker: Dr Abigail Azari (University of Alberta, Alberta Machine Intelligence Institute)

55 Simulation-Based Evaluation of Crosslink Radio Occultation for Lunar Ionosphere Observations

The lunar ionosphere is a ∼100 km thick layer of plasma surrounding the Moon. Despite knowledge of its existence for decades, the structure and dynamics of the lunar plasma remain a mystery due to lack of consistent observational capacity. An enhanced observational picture of the lunar ionosphere and improved understanding of its formation/loss mechanisms is critical for understanding the lunar environment as a whole and assessing potential safety and economic hazards associated with lunar exploration and habitation.

To address the high-priority need for observations of the electrically charged constituents near the lunar surface, the Radio Instrument Package for Lunar Ionospheric Observation (RIPLIO) mission is being developed. RIPLIO would consist of a multi-CubeSat constellation (at least two satellites) in lunar orbit for the purpose of conducting “crosslink” radio occultation (RO) measurements of the lunar ionosphere. This work builds off the concept study for RIPLIO and presents enhanced RO simulations, implementing more realistic models of the lunar ionosphere.

We have constructed models to simulate ionospheric plasma behavior under various heliophysical conditions, including periods when the Moon is exposed to solar wind and when it orbits within Earth’s magnetosphere. The lunar ionosphere models include: an exponential decay model (“Luna 19 fit”), a 3-D photochemical model and the “ARTEMIS model” based on statistical averages of ARTEMIS in-situ observations.

The RO simulations compute the differential phase delay of a dual-frequency radio signal propagating in the modelled lunar ionosphere. Initial results show differential phase delay ranges, depending on frequency pairs, from $10^0$ to $10^3$ cycles within Earth’s magnetosphere and from $10^{-2}$ to $10^1$ cycles under solar wind conditions, suggesting that lower HF signal frequencies and larger frequency spacings (a few MHz) are most responsive to lunar plasma.

The results of this work help in narrowing down the system and operational requirements for RIPLIO, including optimal radio frequency ranges, atomic clock stability, antenna specifications, attitude control subsystem and cost estimates for a mission life cycle. A thorough feasibility study including extensive lunar RO simulations and potential selection of orbital configurations will stem from this preliminary work.

Speaker: Giacomo Radaelli

CAP2025_Abstract_Radaelli.pdf

56 Moving to Learn to See

The Event Horizon Telescope (EHT) is a very long baseline interferometry (VLBI) array that has the capacity to resolve images of supermassive black holes such as Sagittarius A and M87. Turbulence in the interstellar medium distorts images of objects near the galactic center, e.g., Sagittarius A*. This reduces the angular resolution that could be resolved. The scattering screen changes on time scales that are longer than the scales that EHT uses. We utilized a recurrent neural network to mitigate these effects. The model resolves multiple images concurrently by using the long-time scale property of interstellar scattering. We used training samples that are agnostic to General Relativity.

Speaker: Kenny Nguyen (University of Waterloo)

57 Learning to See: Applying Inverse Recurrent Inference Machines to See through Refractive Scattering

The Event Horizon Telescope (EHT) has captured images resolving the horizon of Sagittarius A (Sgr A∗), unveiling a new window into understanding strong gravity and cosmology. Scattering from the turbulent plasma of the interstellar medium distort the appearance of Sgr A, limiting the practical angular resolution of Sgr A. We utilized a recurrent neural network trained on samples ignorant to General Relativistic Magnetohydrodynamics (GRMHD), due to the non-birefringence of Sgr A, we were able to leverage the use of multiple polarizations in the scattering mitigation scheme, demonstrating that it is possible to mitigate scattering well below the instrumental resolution of EHT, 24 µas.

Speaker: Mr Arvin Kouroshnia (University of Waterloo)

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58 Resonant Vibrational Excitation and STEVE

The term Strong Thermal Emission Velocity Enhancement (STEVE) refers to a distinct form of continuum optical emission, an east-west oriented ribbon of mauve light in the near-midnight sky at sub-auroral latitudes. The mechanisms underlying the formation of STEVE are presently unresolved. Using laboratory measurements and the published events of STEVE in the literature (e.g., MacDonald et al., 2018; Gallardo-Lacourt et al., 2018), we investigate the resonant vibrational excitation (RVE) of nitrogen (N2) via the 2g resonance by low-energy (1-5 eV) electron impact, and the dependence of its effectiveness on the plasma conditions (density, composition, and temperature) in the E- and lower F-region. Under the prevailing conditions in the region of Sub-Auroral Ion Drift (SAID), the RVE is found to constitute the dominant underlying mechanism for STEVE, in that it rapidly increases the N2 population above the first ten vibrational levels (v > 11), which leads to the subsequent formation of N2O via radiative attachment, and visible continuum emission. We present a kinetic-photochemical model to describe the dynamic evolution of the vibrational distribution of N2 and the resulting chemical reactions. We present simulation results from our model showing the orders-of-magnitude increase in the N2(v>11) population within 10 minutes of substorm expansion onset and the peak brightness of 5-10 kilo-Raileigh (kR) in the E-region (at 135 km altitude). We discuss our model predictions in the context of the statistical characteristics of observed STEVE events.

Speaker: Andrew Yau (University of Calgary)

(DAMOPC) M2-3 Spectroscopy Applications | Applications de la spectroscopie (DPAMPC)

59 Toward a high-accuracy quantum gravimeter using ultra-cold atoms

Quantum sensors based on cold atoms have demonstrated unprecedented sensitivity, accuracy, and long-term stability that outcompetes “classical” sensors presently used for GPS-free positioning, navigation, and timing (PNT) systems. A crucial part of autonomous navigation is an accurate map of the local gravitational field. Portable absolute quantum gravimeters will enable higher-resolution gravity maps to be realized in airborne surveys, particularly in remote regions of Canada. We present the first results from a table-top quantum gravimeter using atom interferometry with laser-cooled rubidium atoms. This instrument employs optical Raman pulses to coherently split, reflect, and recombine atomic wavepackets in a Mach-Zehnder-like interferometer geometry. The phase shift of the resulting interference pattern provides a sensitive measurement of the gravitational acceleration experienced by the free-falling atoms. This instrument will serve as a high-accuracy gravity reference for future portable gravimeters.

Speaker: Timothy Hunt (University of New Brunswick)

TimothyHunt_CAPcongress_Oral-Abstract_2025_Final.pdf

60 Tunable domain-wall dynamics in multi-domain spin structures in an ultracold 87Rb gas

We study domain wall motion in pseudo-spin-½ ultracold $^{87}$Rb gas initialized in an ‘up-down-up’ configuration, with helical domain walls between the regions of different magnetization. The interplay between diffusive pressure and induced spin-currents due to spin-exchange collisions leads to complex domain-wall dynamics. We qualitatively distinguish two regimes of wall motion. At short times, transverse spin is confined to the domain walls, slowing down domain wall dynamics via exchange collisions. Later, coherence in the domain wall decreases, and the velocity of the wall increases. We demonstrate that spontaneous domain-wall motion may be tuned through altering the initial domain orientation and coherence in the domain wall and have modeled the observed wall trajectories with numerical solutions of a quantum Boltzmann equation. We also use simulations of the quantum Boltzmann equation to train a neural network to predict initial conditions that lead to specific target domain wall trajectories. Achievable spontaneous domain wall trajectories are limited by the restricted phase space of initial parameters; however, optically applying effective magnetic field gradients alters spin currents through the domain wall and offers the possibility of dynamic control of wall motion. We present progress toward this goal using machine-learning techniques to predict time-varying effective magnetic field gradients as control parameters.

Speaker: Olha Farion (Simon Fraser University)

61 Tri-Modal Mosquito Bite Needle Endoscopy (MBNE) for Breast Cancer Diagnostics

Purpose and Hypothesis: To lessen patient discomfort and improve breast cancer biopsy efficacy, a smaller, acupuncture sized needle should be used for core needle biopsies. Minimally invasive Mosquito Bite Needle Endoscopy (MBNE) using a 34-gauge acupuncture-sized needle with WAR tri-modal imaging could improve diagnostic accuracy and reduce unnecessary biopsies.

Methods: An 85-micron multi-core imaging fiber is threaded within the lumen of a 34-gauge needle, creating a probe design. The proximal end of the probe (i.e. the tip of the needle housing the proximal end of the imaging fiber) is inserted into the breast tissue. The distal end of the probe (i.e. the distal end of the imaging fiber) is secured beneath a confocal microscope and aligned with the objective lens. The microscope uses WAR tri-modal imaging to identify the chemical composition of the tissue spot seen by the 85-micron fiber and characterize the tissue spot as healthy or cancerous. WAR tri-modal imaging includes: (W) white light reflectance RGB imaging, (A) autofluorescence contrast imaging, and (R) point Raman spectra collection.

Results: A 34-gauge needle endoscope with 85-µm multi-core optical fiber was developed to capture high-resolution WAR images of breast tissue. A machine learning algorithm was implemented to classify tissue regions using the captured images. The accuracy of the algorithm is being refined via comparison to pathologist-marked images.

Conclusions: A 34-gauge acupuncture-sized needle endoscope integrated with WAR tri-modal imaging demonstrates potential for accurate classification of breast tissue pathology. Thus, the minimally invasive system has the potential to improve patient comfort during breast cancer biopsies and reduce the number of unnecessary 14-18G breast biopsies.

Speaker: Kate Dingle

Abstract - CAP Congress 2025.docx

62 Confocal Microscopy and Tri-modal Optical Imaging for Breast and Thyroid Cancer Detection

Purpose and Hypothesis:
A confocal microscope capable of accurate tissue pathology classification using a WAR tri-modal optical diagnosis system (White-light imaging, Autofluorescence imaging, and Raman spectroscopy) has the potential to improve the specificity and sensitivity to reliably diagnose breast cancer and thyroid cancer. The device will be used to build a database for Raman scattering patterns detected from normal and cancerous breast and thyroid tissue, to classify patient samples. When combined with a needle endoscope, this technology not only has the potential to reduce the false-negative rate of biopsies but also a chance to reduce the amount of unnecessary biopsies and thus the cost of treatment.

Methods:
A confocal microscope that utilizes the WAR tri-modal imaging techniques was designed with three major pathways: (1&2) white light reflectance and autofluorescence imaging via Thorlabs CS895MU CCD camera; (3) Raman collection via the Tornado HyperFlux Pro Raman Spectrometer, using the Thorlabs CLD1010LP laser driver with the LP785-SAV50 785 nm laser diode. Images and spectra are captured ex-vivo.

Results:
WAR tri-modal images were successfully captured from 20+ breast tissue specimens, utilizing white light, autofluorescence, and Raman spectroscopy to differentiate cancerous from non-cancerous regions. Additionally, the first iteration of a machine learning algorithm was created to classify tissue regions as cancerous or non-cancerous. Accuracy is currently being refined by comparing results to pathologist-marked images, with ongoing tests focused on improving classification performance and ensuring alignment with expert diagnoses.

Conclusions:
The integration of confocal microscopy with a tri-modal optical diagnosis system demonstrates the potential for accurate classification of tissue pathology to improve the detection of breast and thyroid cancer. The current confocal microscope requires further optimization and automation before a proper tissue database can be built for breast and thyroid tissue.

Speaker: Alex D'Ippolito (Toronto Metropolitan University)

Alex D'Ippolito - CAP 2025 - Tri-Modal Confocal Microscope.pdf

63 Painted optical potentials for rapid evaporative cooling of neutral atoms

A coherent source of ultra-cold neutral atoms is a crucial prerequisite for state-of-the-art quantum sensors based on matter-wave interferometry, such as quantum gravimeters. Evaporative cooling is typically a slow process, often requiring tens of seconds, hence rapid cooling schemes are desirable to increase measurement rates. We present a numerical model for the evaporative cooling of rubidium-87 atoms in a far-detuned optical dipole trap. The model builds upon previous work for rapid cooling in dynamically shaped optical traps by utilizing time-averaged or “painted” potentials. To achieve greater flexibility in the trapping potential, we consider two independent laser beams whose power and position is modulated in time using a 2D acousto-optic deflector. The simulation solves the coupled differential equations governing the evolution of temperature and atom number during the cooling process while accounting for the rate of elastic collisions, three-body loss effects, and rapid modulation of trap depths and frequency. Our results demonstrate the impact of painted potentials on the cooling rate and atom retention and provide key insights for use in a high-accuracy quantum gravimeter.

Speaker: Cristian Ramirez Rodriguez (University of New Brunswick)

(DCMMP) M2-4 Materials | Matériaux (DPMCM)

64 Chemical intercalation as a versatile technique for property tuning and production of layered materials

Introducing alkali metal atoms between the carbon layers of graphite to form graphite intercalation compounds (GICs), can tune the interlayer spacing and charge the graphite host through a variety of electronic ground states. Hexagonal boron nitride (hBN) is another prototypical layered material and possesses a hexagonal network consisting of B and N atoms. Because of its structural similarity to graphite, there has been several theoretical calculations predicting host-guest redox-driven hBN intercalation compounds. Based on the analogy with GICs, the hybrid structure of hBN and alkali metal atoms that are intercalated into the interlayer spacing may also exhibit interesting electronic properties and utility as a raw material for 2D materials with unprecedented physicochemical properties. However, the intercalation of alkali metal in hBN has proven to be considerably more difficult than graphite. Here, we will present our latest experimental data, showing that potassium metal can be intercalated into hBN layers. The K-intercalated hBN material and films exhibits unprecedented electronic and energy storage properties.5 We will also show new data on the processing and characterization of a new form of 1-dimensional sp3 carbon called carbon nanothreads.

Speaker: George Bepete (Concordia University)

65 Anomalous relaxation mechanism for rejuvenation of stable polystyrene glass

We report on the rejuvenation of thin films of polystyrene (PS) as they are heated from stable glassy states - prepared either through vapour deposition or physical aging. For films with thickness h ≳ 150 nm and less than h ≲ 100 nm the rejuvenation of vapour deposited stable PS glass films follow behaviour well-documented for other stable glasses. This behaviour is quantitatively described by simulations using parameters previously obtained from isothermal rejuvenation measurements in the same material. For films with thickness h ∼ 140nm the behaviour of the vapour deposited films becomes more complicated, and exhibits significant deviations from model predictions. The results are compared with vapour deposited films that are aged after rejuvenation. Collectively, the results of these studies suggest a new distinct mechanism that can result in the rejuvenation of glassy PS, and hence two distinct relaxation processes that can couple to the material density.

Speaker: Saba Karimi (University of Waterloo)

66 Theoretical Insights into Hydrogen-Encapsulated Cage-like Structure and the Elusive High-Pressure Electride of Na-tl50 phase.

Advances in science and technology rely on new materials and molecules with tailored chemical, mechanical, electronic, and superconducting properties. The development of reliable quantum-mechanical approaches has accelerated progress in the discovery of new materials. This is largely owing to the rapid progress of computer power and theoretical methods, particularly density functional theory (DFT) and machine-learned assisted structure prediction methods. Indeed, these computational techniques and theoretical models pave the way for establishing the structure–property relationship for designing advanced materials with novel properties and improving their performances. Using first-principles density functional calculation, we integrated molecular hydrogen into a boron-carbon clathrate framework, and our study reveals a hydrogen-encapsulated hole conductor with an estimated superconducting transition temperature (Tc) of 46 K and dynamically stable at ambient pressure, highlighting it as a candidate for next-generation technologies. Furthermore, by combining a machine learning-assisted structural search with density functional theory (DFT), we successfully resolve the elusive high-pressure tI50 phase of sodium and predicted it to be a high-pressure electride. These findings highlight the unique structural, electronic, and dynamic behaviors of these materials, offering transformative insights into superconductivity and high-pressure physics.

Speaker: Akinwumi Akinpelu (University of Saskatchewan)

67 Machine Learning-Accelerated Study of Potential Energy Surfaces of Group 14 Elements

Scientific and technological advancements in numerous areas of physical sciences and engineering rely on the ability to understand and manipulate the properties of matter at the atomic and molecular scale. Density Functional Theory (DFT) excels in approximating the fundamental equations, the Schrödinger equation describing the quantum behaviour of atoms and molecules. Although DFT is considered as the core of continually growing scientific literature, it is prohibitively expensive for simulating large-sized systems requiring long-time scales and is generally limited to moderate sized (a few hundred atoms) systems. While it is essential to follow the principles from the theory, it is important to recognize that the development and modification of simulation algorithms is an art. In this context, to overcome the challenges posed by DFT, this study employs machine learning approaches to accelerate the exploration of the potential energy surface of group 14 elements, both statically and dynamically. This study uses an integrated machine learning-driven metadynamics approach to expedite the investigation of dynamic evolution of phase transitions, grains, and dislocation defects in large Silicon systems under pressure. [1] By using machine learning to accelerate sensible random structure searches, a novel 8H Germanium allotrope with a direct band gap is predicted, positioning it as a promising material for photovoltaic and optoelectronic applications. [2]

References:
[1] Mangladeep Bhullar, Zihao Bai, Akinwumi Akinpelu, Yansun Yao, Phase Transition in Silicon from Machine Learning Informed Meta-dynamics, ChemPhysChem 2024, 25, e202400090.
[2] Mangladeep Bhullar, Akinwumi Akinpelu, Yansun Yao, Unveiling Novel Direct Bandgap Allotropes of Germanium: A Computational Exploration, Computational Materials Today 2024, 2-3, 100009

Speaker: MANGLADEEP BHULLAR

CAP 2025 abstract.pdf

68 Defect Engineering in 2D Materials for Enhanced Chemical Sensing

This research focuses on the enhancement of two-dimensional (2D) materials such as graphene, transition metal dichalcogenides (TMDs), and MXenes for advanced sensor applications. These materials are celebrated for their ability to detect specific analytes and respond to physical stimuli, making them ideal for a variety of detection strategies in fields ranging from environmental monitoring to medical diagnostics. Despite their known sensitivity and responsiveness to various stimuli, these materials face challenges in selectivity and sensitivity due to interference and noise. This study aims to computationally investigate the impact of engineered defects, specifically substitution and vacancy defects, on the sensing properties of these materials. By applying Density Functional Theory (DFT) within the Quantum Espresso software, our study models the interaction of defected 2D materials with impurities in the environment such as volatile organic compounds (VOCs), gaseous molecules such as NH3, and CO2. The research will explore how these defects, including doping of the lattice with elements like boron, nitrogen and creation of vacancy sites, enhance adsorption and charge transfer processes. Our findings aim to significantly improve the performance of sensors by increasing their sensitivity and selectivity, potentially revolutionizing industries such as public health and safety, environmental monitoring, and biotechnology. The outcomes will also provide deeper insights into the fundamental properties of 2D materials interacting with complex molecular systems, potentially opening new avenues for their use in advanced sensor and quantum technologies.

Speaker: Ghazaleh Gholizadeh

(DQI) M2-5 | (DIQ)

69 Nonunitary operators in quantum information and distributed quantum computing

In this talk, we will consider quantum-information-theoretic settings in which nonunitary operators arise naturally, including 2-dimensional extensions of the ZX-calculus. We apply this perspective to scenarios in distributed quantum computing and quantum networking where the actualization of asynchronous, low-latency quantum communication protocols necessitates nonunitary gates for correct behaviour. The talk draws upon several separate joint projects with, respectively, M. Azam (arXiv:2210.03556); J. Bell and F. Butler (in preparation); and J. Peckham and D. Makharoff (arXiv:2407.14987). Nonetheless, there is a continuous narrative across these works.

Speaker: Steven Rayan (quanTA Centre / University of Saskatchewan)

70 Extracting Entangled Pulses from Continuous-Wave Photon Sources

Squeezed light is a versatile resource for optical quantum computing, sensing, and communication. However, light sources usually require extensive and precise optimization for generating a pulse with the desired shape, resulting in inflexible state preparation. In our work, we address this problem by presenting a protocol for extracting pure squeezed states with arbitrary pulse shape by “cutting out” the desired output from a collection of squeezed modes. We achieve this by using the nullifier formalism to describe the state of the output modes, and show that selective heterodyne detections on temporal modes will cause the desired state to be disentangled from other, undesired modes. We find that using this method we are able to deterministically prepare single- and two-mode squeezed state in any shape from a continuum source, and projectively measure arbitrary states in any pulse onto the squeezed bases.

Speaker: Christopher Kallio (Simon Fraser University)

71 Discrete-Variable-Assisted Error Correction of Continuous-Variable Quantum Information

Quantum information can be encoded as continuous wave functions in bosonic modes, but implementing error correction for such continuous-variable (CV) information remains a significant challenge. In this work, we propose a novel CV quantum error correction (QEC) scheme that leverages auxiliary discrete-variable (DV) systems as resources. By applying appropriate hybrid CV-DV coupling, we show that the fluctuation of mode quadratures induces a geometric phase on the DV system. Measuring the DV system thus enables the estimation and subsequent correction of the CV fluctuation noise. We demonstrate that even a single auxiliary qubit can suppress infidelity by 18%, and further improvement is possible by using higher-level ancilla. Furthermore, we propose that the DV ancilla can be encoded in noisy bosonic modes with established DV QEC. This introduces a new class of oscillator-in-oscillator code that is fundamentally different from the only known code, which relies on difficult-to-prepare GKP states.

Speaker: Neginossadat Razian (Simon Fraser University)

72 Continuous-Variable Analogue of Measurement-Based State Preparation for GKP Encoded States

Quantum error correction (QEC) is essential for fault-tolerant quantum computing, protecting quantum information from noise and decoherence. The Gottesman-Kitaev-Preskill (GKP) encoding is a leading QEC scheme in continuous-variable (CV) quantum computing, offering robustness against displacement errors. However, a major challenge in GKP encoding is efficiently generating non-Pauli eigenstates, which are required for universal quantum computation. While Clifford operations can be implemented using Gaussian optical elements, achieving non-Clifford transformations typically requires nonlinear interactions, which are experimentally demanding.
In this work, we introduce a novel measurement-based approach to generating non-Clifford logical states in GKP encoding. Inspired by measurement-based quantum computation (MBQC), we construct a two-mode photonic cluster state by interfering two squeezed GKP states on a beamsplitter. By applying a phase shift to one mode before performing homodyne measurement, we induce a transformation on the remaining mode. We explore how tuning the measurement basis in a rotated phase space affects the post-measurement state. Our results show that for specific rotation angles, the measurement collapses the remaining mode into a non-Pauli eigenstate, including potential magic states. This provides an experimentally feasible method to generate non-Pauli eigenstates.
Our findings demonstrate a practical approach to state engineering in photonic architectures, a promising platform for scalable quantum computing. This measurement-based strategy circumvents the need for direct nonlinear interactions, paving the way for more accessible implementations of universal quantum computation with GKP-encoded states.

Speaker: Fariba Hosseinynejad (Department of Physics and Astronomy, University of Calgary)

73 Survey of all additive quantum codes for small systems via graphs

Scalable, fault-tolerant quantum computing depends on the development of efficient quantum error correction codes. While many good quantum low-density parity-check (qLDPC) codes have been introduced, there is still potential to discover better ones, particularly for small numbers of qubits relevant to the current era of noisy intermediate-scale quantum devices. This research systematically searches for efficient and useful codes by exhaustively analyzing all possible additive codes for small numbers of physical qubits $n$ through a graph representation. Specifically, we examine all non-isomorphic connected simple graphs for $n\leq 10$, and likewise all bipartite graphs for $n\leq 14$ corresponding to CSS codes. Our findings include codes that saturate quantum coding bounds, are competitive with topological codes requiring much larger values of $n$, are suitable for architectures with local connectivity, and which provide insights into the graph patterns of families corresponding to good codes for larger qubit systems. This work helps to lay the foundation for a systematic code design framework for large-scale quantum systems.

Speaker: Mohsen Mehrani (University of Calgary)

(DNP) M2-6 Nuclear Structure | Structure nucléaire (DPN)

74 Radioactivity of Rare Isotopes

For me, one of the most exciting things about studying radioactive decays of rare isotopes is the wide variety of science questions that can be addressed. Precision measurements of nuclear beta decay can be used to constrain properties of the weak interaction and test the Standard Model of particle physics, delayed particle emission offers insight into unbound resonance states that are populated in explosive nuclear astrophysics, and gamma-ray emission is essential for elucidating the structure of the atomic nucleus and determining half-lives. In this talk, I will give an overview of our decay studies program at TRIUMF, which will include recent results obtained with GRIFFIN at ISAC-I and the goals for the upcoming Active Target and Time Projection Chamber (ACTAR TPC) campaign of experiments at ISAC-II.

Speaker: Prof. Gwen Grinyer

75 Mirror Symmetry in the f7/2 Shell below 56Ni: Excited States and Electromagnetic Transition Rates in 55Ni and 55Co

Nuclear theories often operate under the assumption that the strong nuclear force is independent of electric charge. As a result, it is expected that exchanging the number of protons with the number of neutrons in a nucleus will produce a mirror nucleus with identical structure after electromagnetic considerations. However, due to the charge dependence of the strong nuclear force, isospin non-conserving interactions give rise to quantities like Mirror Energy Differences between analogous excited states in mirror nuclei which cannot be accounted for by Coulombic forces.

This charge dependence is being explored at TRIUMF, Canada’s particle accelerator centre. Stable $^{20,21}$Ne and radioactive $^{21}$Na beam experiments were conducted with $^{40}$Ca targetry for production of $^{55}$Co and $^{55}$Ni through fusion evaporation. These experiments leverage: TRIUMF’s Isotope Separator and ACcelerator (ISAC) beamline for delivery of high-intensity radioactive beams; the TRIUMF-ISAC Gamma-Ray Escape Suppressed Spectrometer (TIGRESS) for gamma-ray detection; SFU’s TIGRESS Integrated Plunger (TIP) for charged particle detection; TRIUMF’s Electromagnetic Mass Analyzer (EMMA) for measurement of the A, Z, and energy loss of residual nuclei; as well as specialized $^{40}$Ca targetry carefully protected from oxidation.

This presentation will focus on highlighting the selectivity offered by combining TIGRESS, TIP, and EMMA for lifetime and electromagnetic transition rate measurements, as well as the present state of the ongoing analysis. In the longer term, this work aims to explore the f$_{7/2}$ hole configurations in $^{56}$Ni and electromagnetic transition rates for excited states of $^{55}$Ni and $^{55}$Co. Ultimately, these measurements enable an investigation into the charge dependence of the strong interaction.

Speaker: Heinz Asch (Simon Fraser University)

76 The 8pi BGO Ball Array and Its Application to 3-Gamma PET

Many nuclear science experiments require gamma-ray spectrometers that offer resolution, efficiency, and selectivity. Systems that excel at all three are rare, but the 8pi gamma-ray spectrometer finds a balance between them, making it a powerful tool for gamma-ray spectroscopy.
Over the past year at Simon Fraser University, the 8pi Bismuth Germanium Oxide (BGO) ball array has been brought into operation. It is an assembly of 132 BGO scintillator detectors arranged in an icosahedral geometry, covering nearly the full solid angle around a sample chamber. Coupled with a digital data acquisition system, the 8pi provides time-resolved gamma-ray spectroscopy with online event filtering capabilities. While currently operating with the BGO ball array, the 8pi can also facilitate 20 Compton-suppressed High-Purity Germanium (HPGe) detectors for high-energy resolution spectroscopy.
The current BGO ball configuration supports various nuclear science experiments such as the detection of rare 3-gamma positronium decays, which is relevant to Positron Emission Tomography (PET) scans. While positron annihilation typically results in 2-gamma emissions, about 0.5% of the time, 3-gamma emission occurs. Using conservation laws, a single 3-gamma detection is sufficient to calculate the location of positron annihilation, unlike traditional PET, which requires multiple 2-gamma detections. This offers a new approach to PET imaging which is difficult to study with simple gamma-ray spectrometers. But with 8pi, these 3-gamma measurements are practical due to its unique combination of capabilities. This talk will review the 8pi spectrometer’s current status and application to PET.

Speaker: Joshua Yu (Simon Fraser University)

77 Spectroscopic study of 114Sn following the beta decay of 114Sb using Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei (GRIFFIN)

The experimental studies of semi-magic Sn ($Z$ = 50) isotopes continue to be of significant interest as they provide valuable insights into the fundamental nucleon-nucleon interactions and offer suggestions for improvements in theoretical models.
The mid-shell Sn isotopes ($A$ = 112-122) exhibit shape coexistence, which is characterized by the presence of intruder proton 2p-2h deformed bands built on the excited 0$^+$ states in the vicinity of the ground-state bands.
Recent spectroscopic studies of these mid-shell nuclei have reported different bandheads (viz., the 0$^+_2$ state in $^{118}$Sn and the 0$^+_3$ state in $^{116}$Sn) for the deformed 2p-2h band in these isotopes. In order to investigate how the properties of these shape-coexisting structures evolve along the Sn chain, a comprehensive study of neighboring $^{114}$Sn nucleus was performed, incorporating gamma-ray spectroscopy, conversion electron measurements, and lifetime measurements.
The excited states in $^{114}$Sn were populated via the $\beta^+$ decay of $^{114}$Sb, which was produced at the TRIUMF-ISAC facility. The gamma rays emitted following the $\beta$ decay were detected using the GRIFFIN spectrometer, consisting of 15 Compton-suppressed HPGe clover detectors. Additionally, a fast scintillator and an array of five Si(Li) detectors were used for $\beta$-particle and conversion-electron spectroscopy, respectively, while eight LaBr$_3$(Ce) scintillators were employed for fast timing measurements.
Preliminary analysis reveals evidence of several new transitions in $^{114}$Sn. Specific spectroscopic results pertaining to the level scheme, angular correlations and lifetime measurements will be presented.

Speaker: Madhu Madhu (Simon Fraser University)

CAP2025_Abstract_114Sn.pdf

78 Direct Measurement of Resonance Properties of 23Mg (p, γ)24Al reaction Occurring in Classical Novae using the DRAGON Recoil Separator and an optimized Array of LaBr3, CeBr3 and BGO Gamma Detector Array

Classical novae are significant contributors to the cosmic abundance of several isotopes, including, 13C, 15N, 26Al and the radioactive 22Na. Observations of these elements in the ejected material help astrophysicists study the processes governing stellar evolution and nucleosynthesis. One particular nucleosynthesis site is classical novae, which are explosions resulting from accretion of hydrogen-rich material onto White Dwarf star are responsible for the formation of a significant number of nuclides lighter than calcium. One of the main reactions that has an observable effect on classical nova nucleosynthesis is the proton capture on radioactive 23Mg, resulting in 24Al recoil and a gamma ray. The 23Mg(p, γ)24Al reaction has been investigated through a variety of experimental and theoretical means in the past. These investigations include a direct measurement of the strength and energy of the dominant resonance in this reaction, using a radioactive 23Mg beam at the DRAGON facility at TRIUMF in 2010. Although this measurement effectively detected the 24Al recoils in coincidence with γ rays, the beam energy was slightly too low. Hence it is possible that beam might have reached the resonance energy in non-equilibrium region of the target, invalidating the results. This was evident in 2015, when a high-resolution mass measurement of 24Al suggested a resonance energy that is inconsistent with the DRAGON result.
Due to the existing inconsistency in resonance energy of the 23Mg(p, γ)24Al reaction, this research aimed to investigate the resonance properties of the reaction by using a higher 23Mg beam energy coupled to an array of newly installed hybrid fast timing Lanthanum Bromide (LaBr3), Cerium Bromide (CeBr3) and Bismuth Germanate (BGO) detectors for detecting γ- rays. This newly installed detector array allowed a precise measurement of the strength of the resonant state, extracting a value of 35 ± 5 meV, which is in excellent agreement with the Erickson et al., experimental resonance strength of 38_(-15)^(+12) meV. The newly determined reaction rate is incorporated into NuGRID nova simulation code to study its impact on nucleosynthesis and isotopic abundances in classical novae.

Speaker: Edwin Amanda Crystal (Saint Mary's University, Halifax)

Abstract- Edwin Amanda Crystal.pdf

(DPE) M2-7 Physics Education I | l’enseignement de la physique I (DEP)

79 Emergent Explicit Regulation in Science Classrooms

Small-group activities have been adopted widely in science and engineering classrooms. Research on collaborative learning has showed that some groups are more productive (in terms of meeting the learning goals of the program) than others, even if all the groups are taught by the same instructor, and are engaging in the same tasks. To be productive, groups must be regulated. Group regulation is defined as groups adaptively responding to challenges in order to optimize group learning.

In the video data we use for our work, first year students are engaged in small group scientific inquiry. The activities are also developed to promote students’ group collaboration and reflective thinking. Activities of different types —such as reading and discussing scientific articles, designing and conducting experiments, model building— were analyzed. First we broadly explored the videos, and noticed self-initiated group regulations emerging in different kinds of activities across different groups. We then conducted thematic coding identifying typical examples of the group regulation phenomena and examining them more closely.

From this we have identified a set of contextual and behavioural features of the observed group regulation and named the phenomena emergent explicit group regulation (EER). We understand EER as an “in the moment,” or emergent, regulatory response to a challenge faced by the group. We have also categorized the EER identified based on their target areas of regulation.

In this talk, I will discuss how to analyze video data generally using EER as a specific example. I will then discuss our current results on the types of EER and their distribution found in our data.

Speaker: Pierre-Philippe Ouimet

80 Use of MathMatize website for in-class and post-class formative assessments in large classes

We will demonstrate how we use the MathMatize website both for in-class polls and post-class quizzes in several first- and second-year large physics classes. MathMatize is a relatively new system which supports fill-in-the-blank style questions where students input equations, and the system is very good at recognizing equivalent answers. We find that this system works much better than multiple choice questions, especially for the second-year courses where, for example, we can get students to set up integrals during class and get immediate feedback on any mistakes.

Speakers: Ania Harlick (University of Toronto), Brian Wilson (University of Toronto)

81 Comparison of the experiences of Female and Male Students in taking Labatorials

Labatorials (combination of “lab” and “tutorial”) developed at the University of Calgary were inspired by the introductory physics tutorial system entitled ‘Tutorials in Introductory Physics’ at the University of Washington. Students doing Labatorials typically use worksheets with several suitable activities for the duration of the lab session. The worksheets ask students to run calculations, plot graphs and do experiments, they can also include instructions for experiments and computer simulations Labatorials use pre-understanding-targeting worksheets similar in structure to those in tutorials, except with additional emphasis on experiments. Students are assigned to groups of 3 or 4 members and provided with conceptual questions and asked to make predictions.
It has been shown “that female students with A's have similar physics self-efficacy as male students with C's in introductory courses. Moreover there is a continuing low percentage of women in science and engineering. Despite some efforts progress has been slow.
Kalman, La Braca, & Sobhanzadeh, (2020) noted that in performing Labatorials, there were indications that beyond simply working together for the purpose of completing the lab, both male and female students have found reassurance in knowing that they were going through similar struggles, helping them feel comfortable in sharing their doubts and feeling relatively relaxed despite the challenges of the labatorials.
We present preliminary results on a study to see if indeed women students have the same experiences as male students when they undertake Labatorials. Using a mixed-methods approach, this study collects qualitative and quantitative data, including pre-tests, post-tests, reflective writing assignments, interviews, and teaching assistant feedback. The research is conducted at Concordia University in Montreal and Mount Royal University in Calgary, with student groups composed of mixed genders to foster peer collaboration and inclusive learning.

Speaker: Ms Lydie Lachance (PhD student)

CAP talk 2025.docx

82 Mastery-Based Assignments for Large Enrolment Introductory Physics Courses

In this talk, we will present a mastery-based approach to introductory physics assignments (i.e., homework), and the results of a study comparing this mastery-based method to a standard online (large publisher) assignment software. We then will discuss the implementation of this method to a large enrolment introductory physics course. In the past decades, introductory physics courses at Canadian universities have increasingly relied on online assignment systems to manage the delivery, submission and grading of students take home assignments. These standard online systems face common issues such as a lack of detailed feedback and solutions (leaving students frustrated not knowing the cause of their errors/ unable to learn from their mistakes) and an over-emphasis on final answers (with associated algebraic solutions available on the internet). The mastery-based method we present involves two parts to each assignment, an initial traditional written submission, and a re-submission after detailed solutions have been released to the students; this two-part process allowed for the elimination of intensive grading resources, while allowing students to focus on detailed process-based written solutions and proper corrections to all errors in their re-submission. Students who were part of the study completed an entire introductory physics course with each assignment method. Results strongly favored the mastery-based method in all significant categories assessed in the study, with students reporting increased understanding of how to approach and complete introductory physics problems, as well as decreased stress and frustration, as primary benefits.

Speaker: Mark Robert Baker (Western University)

83 Strengthening Math Foundations in PHYS 100: A Targeted Workshop Approach

At Simon Fraser University, PHYS 100 is a large introductory physics course designed for students who have not taken Physics 12 (or its equivalent). Since Physics 12 is a prerequisite for the university-level physics courses required in many physical and life sciences programs, PHYS 100 serves as a crucial stepping stone for some students pursuing these fields. However, many students entering PHYS 100 lack the essential mathematical skills required for problem-solving, creating a significant barrier to success.

A pre-term math boot camp could help bridge this gap, but logistical and financial constraints make this type of early intervention challenging. To address this issue, we implemented a 20-question multiple-choice diagnostic test at the beginning of the term to assess students' proficiency in four key areas of high school math: proportional reasoning, trigonometry, graphing, and exponents/logarithms. Students who answered fewer than 3 out of 5 questions correctly on any topic were given an incentive to attend targeted workshops addressing their specific skill gaps.

Each 90-minute workshop consisted of a mini-lecture followed by an active problem-solving session, where students worked at whiteboards in randomly assigned groups of three. The workshops were offered twice—once in the first four weeks and again later in the term. We analyze differences in attendance based on the timing within the term and the workshop topics.

To evaluate the impact of these workshops, we compare the final average grades of students who attended versus those who did not, taking their diagnostic test scores into account. I will discuss the effectiveness of targeted math support in enhancing physics problem-solving abilities. Beyond addressing immediate skill gaps, this approach may also encourage students to reflect on their prior knowledge and identify areas for improvement—an essential aspect of learning in physics and beyond.

Speaker: Olha Farion (Simon Fraser University)

(DPMB) M2-8 | (DPMB): Magnetics, Molecules, and Measurements: Next-Gen Tools in Medical Physics

84 Advancing Surface-Enhanced Vibrational Spectroscopy for Molecular Detection

Vibrational spectroscopy techniques, including Raman and infrared (IR) spectroscopy, have gained significant attention for their ability to provide molecular fingerprints with high specificity. By leveraging plasmonic nanostructures, Surface-Enhanced Raman Spectroscopy (SERS) and Surface-Enhanced Infrared Absorption (SEIRA) further enhance the detection sensitivity, enabling trace-level molecular analysis. In this study, we explore the potential of SERS and SEIRA for the sensitive and selective detection of target molecules, demonstrating their application in bio-chemical sensing domains.
To develop the sensor, we deposited gold thin film substrates using the pulsed laser ablation technique suitable for resonance with the excitation 785 nm Raman lasers. Graphene-integrated substrates were utilized to achieve optimal enhancement for IR sensing modalities. The study involves systematic concentration-dependent investigations to evaluate detection limits and spectral reproducibility. Computational support via Density Functional Theory (DFT) aids in the assignment of characteristic vibrational peaks, ensuring accurate molecular identification and interpretation.
By integrating experimental and computational methods, this study aims to establish a robust vibrational spectroscopy platform for the analysis of molecular system. The findings contribute to the development of advanced sensing strategies with potential future applications in biomedical diagnostics and pharmaceutical analysis.

Speaker: Janani Balasubramanian (Nano-imaging and Spectroscopy Laboratory, Faculty of Science, University of Ontario Institute of Technology)

CAP_2025_abstract - BM.docx

85 Development of a fiber optic detector for temperature measurements of medical isotope production targets

Medical isotopes are a vital aspect of nuclear medicine. They are essential for positron emission tomography (PET) and single photon emission computed tomography (SPECT), which aid with early detection of cancers, and isotopes are also used in some treatments, such as targeted radionuclide therapy. However, the yield of cyclotron-produced isotopes is lower than its theoretical potential. To improve target design and increase production, existing target models require validation by integrating real data of factors affecting isotope yield. One of these components is the temperature within targets during irradiation. The temperature distribution is not well known due to the difficulty of accurately measuring temperature in the harsh radiation environment. This work explores the use of gold-coated silica fibers engraved with three fiber Bragg gratings (FBG) to measure the temperature of liquid medical isotope targets.
FBGs are small, radiation-resistant, and capable of withstanding high pressures and temperatures, which makes them ideal for this application. Furthermore, the relationship between the FBG wavelength and temperature is linear with an average R$^2$ value of 0.993, as determined during the fiber calibration.
My preliminary work, investigating the heat transfer coefficient of helium by inducing phase changes in foil targets and using FLUKA/ANSYS simulation software will also be significant for the improvement of existing target models. Additionally, I tested the performance of a fiber support system to assess its durability and ability to securely hold fibers during an irradiation. The results from both these studies will facilitate future work where the capabilities of FBGs are broadened to gas and solid targets, further expanding their potential utility in nuclear medicine applications.
This research contributes to the growing field of nuclear medicine by introducing a novel approach to temperature measurement in cyclotron targets, with the capacity to increase isotope production efficiency. With increasing demand for medical isotopes, developing more efficient methods to measure and optimize production processes will be valuable by helping to advance cancer research and introduce additional treatment options to clinics.

Speaker: Grace Dehnel

86 Splittable wireless resonator array for intraoperative MRI

Introduction: Intraoperative MRI (iMRI) 1,2 provides real-time imaging during surgery. This is crucial in neurosurgery for precise targeting and complete resection of tumours, reducing the risk of residual tissue and the need for repeat surgeries. For imaging, a radiofrequency (RF) coil must be placed around the head. For effective use in surgery, the top part of the coil should be easily removable, sterile, and sometimes disposable. Standard close-fitting helmet arrays with complex cables are unsuitable. To address this challenge, we test a low­ cost, cable-free, and splittable wireless resonator array designed specifically for iMRI.
Methods: The coil is a wireless resonator array consisting of two split halves. The top half contains one large loop resonator, while the bottom half includes a four-element, highly decoupled loop array. The bottom half is integrated with the head fixation system and remains stationary throughout the surgical procedure.
MRI was performed on a cylindrical phantom and on the human head to demonstrate the SNR performance. Three scenarios were investigated:(1) the wireless resonator array with the body coil, (2) the wireless resonator array with the 8-channel tilted array, with an acceleration factor of 2 in the AP direction for the human images and (3) a commercial 12-channel head array from Siemens, which served as a baseline for comparison. Data collection and use was approved by the local IRBs. The default body coil was used for RF transmission, with the wireless resonator array detuned or deactivated where applicable.
Results: Compared with the Siemens 12-channel head array, the wireless resonator array demonstrates similar SNR in the top and central areas and approximately 20% higher SNR in the bottom area, whether using the body coil or the local tiled receive array as the primary coil. For parallel imaging, the wireless+ tiled 8-channel array configuration produced lower maximum/average g-factors than the Siemens head array and produced clinically usable images with sufficient coverage of the entire brain.
Discussion and conclusion: In this work, we demonstrated the use of a splittable wireless resonator array for iMRI, in which the top half can be easily removed. The coil provided comparable or better SNR to a commercially available wired coil.
Acknowledgement
We thank NSERC for funding.
Reference
1.Black PM, Moriarty T, Alexander Ill E, Stieg P, Woodard EJ, Gleason PL, Martin CH, Kikinis R, Schwartz RB, Jolesz FA. Development and implementation of intraoperative magnetic resonance imaging and its neurosurgical applications. Neurosurgery. 1997 Oct 1;41(4):831-45.
2. Jolesz FA. Future perspectives for intraoperative MRI. Neurosurgery Clinics. 2005 Jan 1;16(1):201-13.
3. Zhu H, Zhang Q, Li R, Chen Y, Zhang G, Wang R, Lu M, Yan X. Detunable wireless resonator arrays for TMJ MRI: A comparative study. Magnetic Resonance Imaging. 2024 Sep 1;111:84-9.

Speaker: Ms Yujie Ren (University of Winnipeg)

Splittable wireless resonator array for intraoperative MRI.docx

(PPD) M2-9 Searches for dark matter I | Recherche de la matière noire I (PPD)

87 Status of the SuperCDMS Experiment at SNOLAB

The Super Cryogenic Dark Matter Search (SuperCDMS) direct detection experiment focuses on the search for low-mass (< 10 GeV/$c^{2}$) dark matter particles. It is currently being installed 2 km underground at SNOLAB, Canada. The payload will consist of 24 cryogenic germanium and silicon detectors arranged in four towers with six detectors each. The detectors come in two varieties, called HV and iZIP. The HV detectors are equipped with phonon sensors and are operated at $\sim$100 V to benefit from the signal amplification provided by the Neganov-Trofimov-Luke effect and achieve a lower threshold. The iZIP detectors have both phonon and ionization sensors, which allow them to discriminate between electron and nuclear recoils, thereby considerably reducing the background. Presently, the experiment is scheduled to begin commissioning in mid-2025, followed by the start of the first science run in late 2025. This talk will provide an overview of the experiment and describe its current status.

Speaker: Tyler Reynolds (University of Toronto)

88 Modelling the electric field in SuperCDMS High Voltage Detectors

The Super Cryogenic Dark Matter Search (SuperCDMS) collaboration uses cryogenic silicon and germanium detectors to search for evidence of dark matter. The collaboration utilises Monte Carlo simulations to examine the predicted response of these detectors to energy depositions by dark matter particles via nuclear recoil. The detectors produce signals through creation of electron-hole pairs within the detector bulk which are then accelerated by the voltage difference applied on the faces of the detector. Thus an accurate Monte Carlo simulation requires an accurate model of the electric field within the detector. The E-field modelling was first done for the SuperCDMS HVeV gram-scale prototype detectors, which at a smaller scale allowed for the establishment of a framework that was then generalised to the full-scale SuperCDMS HV100mm detectors. The E-field models were then used in Monte Carlo simulations based on Geant4 and G4CMP to study particle transport within the bulk of the detectors. This talk will cover the simulation framework created in COMSOL Multiphysics simulation software to implement QET designs for accurate E-field modeling alongside the challenges and approximations required in extending individual detector models to a full-scale detector tower model consisting of 6 detectors that represents the SuperCDMS as-built geometry at SNOLAB. Ultimately I present the simulation data extracted by the Monte Carlo simulation using the E-field models of the detectors.

Speaker: Souren Salehi (University of British Columbia)

89 Effect of electronegative impurities in NEWS-G's dark matter detector

The NEWS-G collaboration uses spherical proportional counters to search directly for low-mass dark matter. Each counter is a metallic sphere filled with gas with high-voltage anodes at its centre producing a radial electric field. The interaction between a dark matter particle and a nucleus can ionize the gas, which leads to electron avalanches near the anodes and a detectable signal. The latest NEWS-G detector is a 140 cm diameter copper sphere currently taking data with various gases at SNOLAB.

Like many sensitive detectors of various types, we have found an unexplained excess of low-energy events, which is the main limit on NEWS-G's sensitivity. Our working hypothesis was that this relates to electron attachment to electronegative impurities, such as oxygen, in the detector gas. In fall 2024, we injected two small boluses of air into our detector volume (O$_2$ concentration of 11 ± 1 ppm each in 1400 L) and found proportionate changes in certain types of event. I will introduce the detector and discuss the issue of attachment, including the results of this injection experiment.

Speaker: Jon Clarke (Queen's University)

90 Thermal Simulations for the Scintillating Bubble Chamber Dark Matter Experiment

The Scintillating Bubble Chamber (SBC) collaboration combines historic bubble chamber technologies with the scintillation properties of liquid nobles to create a detector uniquely suited to low threshold rare event searches. The collaboration has built two nearly identical assemblies, SBC-LAr10 is meant for calibration studies and future coherent elastic neutrino-nucleus scattering research at Fermilab, and SBC-SNOLAB is bound for a low background dark matter search. SBC uses a superheated xenon-doped liquid argon active volume, allowing for event by event energy reconstruction, electron-recoil insensitivity, and a projected 100 eV threshold. The cryogenic nature of the detector presents an interesting opportunity to look further into the low temperature properties of both the active volume and CF$_4$ hydraulic fluid at the 30 PSI operating pressures of the detector. This talk will outline the current status of both SBC-LAr10 and SBC-SNOLAB, as well as briefly discussing the potential for estimating cryogenic properties of the detector constituents.

Speaker: Ezri Wyman (Queen's University)

91 Energy and position reconstruction in the Light only Liquid Xenon (LoLX) experiment

The Light-only Liquid Xenon (LoLX) experiment operates at McGill University in collaboration with TRIUMF. The experiment uses silicon photomultipliers (SiPMs) to examine liquid xenon (LXe) scintillation characteristics for detecting rare physical events, such as neutrinoless double beta decay or dark matter. The primary goals are to understand SiPM performance and study LXe scintillation characteristics in the light-only channel. The LoLX phase 2 detector is a 4-cm cube consisting of two types of SiPMs—HPK VUV4 and FBK HD3—and a VUV-sensitive photomultiplier tube (PMT). During the first commissioning run, we used external gamma sources to study the detector's performance. To study the position-dependent event response, we developed a detailed photon propagation simulation using Chroma, a GPU-based photons simulation framework. In this work, we combined experimental data with light propagation simulations to perform energy and position reconstruction, helping us understand the intrinsic liquid xenon scintillation light production and resolution.

Speaker: Xiang Li (TRIUMF, Simon Fraser University)

92 DEAP-3600 Hardware Upgrades and Third Fill

DEAP-3600 is a single-phase liquid argon detector designed to probe for high mass WIMP dark matter candidates. A global collaboration, DEAP has previously run from 2016 to 2020 in the Cube Hall at SNOLAB. From extensive background modeling a small background rate was expected in the WIMP region of interest. These events were predicted to originate in two ways: Either shadowing caused by the neck geometry or direct energy degradation caused by dust particulates in the liquid argon. The former was addressed by implementing new neck flow guides that are coated with Pyrene doped polystyrene, a material with a significant difference in time constant to that of argon, to allow the events be easily tagged. The latter was addressed with a new particulate removal system. New process lines were added so that liquid can be removed from the detector, filtered, and reintroduced to the detector in a clean safe way. There are also redundant mitigations for both backgrounds included and are available if needed. The installation of these upgrades was finished in February 2025, and the procedure to begin the third fill of DEAP-3600 is currently underway, with completion expected in August 2025.

Speaker: Austin Murray

15:45 Health Break | Pause santé

15h00-15h15 - HS Workshop Break; followed by 16h00-17h30 Tours

M-PLEN3 Achievement Medal Plenary Session | Session plénière - Hong Guo, McGill U.

93 Computational electronics: from classical to quantum devices

Technology Computer-Aided Design (TCAD) refers to software tools used for modeling semiconductor devices and fabrication processes. As we approach fundamental scaling limits, TCAD must evolve to address new critical frontiers of hardware design: nanoelectronic devices requiring atomic-scale precision and quantum technologies demanding fundamentally new simulation approaches. Over three decades, with our collaborators we worked to develop theoretical formalisms and reduce them to practically useful software of atomistic-TCAD and QTCAD to meet the new challenges of modern computational electronics. I will discuss the present status of this research domain. As examples, predictions of atomistic-TCAD of a novel FET design to achieve low power transistor operation, and predictions of QTCAD on donor spin qubits, will be presented and compared to experimental measurements. The atomistic-TCAD and QTCAD frameworks provide powerful new tools for physics research and technology innovation.

Acknowledgements. I am profoundly grateful to CAP for this honor. This honor represents the collective achievement of an extraordinary team of students, postdocs, and collaborators whose creativity and dedication made these advances possible. Financial support from the federal and Quebec granting agencies, McGill University, and industrial partners are greatly appreciated. I thank the Digital Research Alliance of Canada for substantial computational support.

Speaker: Hong Guo (McGill Univresity)

16:45 Travel Time | Durée du voyage

Welcome Reception with BBQ | Réception d'accueil avec BBQ

18:30 Travel Time

Book signing event at Western Development Museum - Her Space Her Time by S. Ghose

M-HERZ Herzberg Memorial Public Lecture | Conférence publique commémorative Herzberg

19:45 Welcome and Introduction

94 Preparing for Quantum 2.0

From lasers to electronics and atomic clocks, quantum science has already transformed our lives. Now, emerging technologies such as quantum computers, sensors and quantum communications, offer the promise of a second quantum revolution. What makes quantum information processing so powerful? How does one cut through the hype to honestly assess its potential? Are you ready to participate in Quantum 2.0? Find out more in this talk.

Speaker: Shohini Ghose (Wilfrid Laurier University)

20:45 Q&A Session and Thank You's

Tuesday 10 June

07:30 Congress Registration and Information (07h30-17h00) | Inscription au congrès et information (07h30-17h00)

08:45 Plenary hall opens | Ouverture de la salle plénière

T-PLEN1 Plenary Session | Session plénière - Pieter Cullis, UBC

95 Design of lipid nanoparticles to enable gene therapies

Delivery of nucleic acid-based drugs into target cells in vivo has been a major challenge for enabling gene therapies. This barrier is now being overcome due in part to advances made in lipid nanoparticle (LNP) delivery systems. LNP systems enable the mRNA COVID-19 vaccines and there are a host of LNP RNA vaccines and therapeutics in clinical development. Advantages of LNP RNA systems over other delivery vectors include safety, ability to re-dose, essentially unlimited genetic cargo, ease of design, straightforward manufacturing processes, lower cost, and potential for highly personalized targeted therapeutics that can be developed in a matter of weeks. In this talk I will discuss the evolution of lipid nanoparticles and lead examples of therapeutic applications of LNP RNA systems to treat cancer, cardiovascular disease and rare diseases.

Speaker: Pieter Cullis (University of British Columbia)

09:45 Health Break | Pause santé

(DAPI) T1-1 | (DPAI) Advances in Radiation Detection, Simulation, and Low Background Techniques

96 The SNOLAB Low Background Measurement Program

Many experiments which require very low levels of background radiation are located deep underground as the deep underground facilities provide significant rock overburden and commensurate reduction in the cosmic ray flux and cosmic ray-spallation induced products. However, even when an experiment is deep underground there are still backgrounds present, these can include high-energy cosmic ray muons which pass through the rock overburden that then interact with the experiment or rock nearby the experiment, and the detector environment itself, which can include the radioactivity naturally emitted from the surrounding rock and the materials used to build the experiment. Since many of these backgrounds may be present in the underground environment, it is highly desired to measure these backgrounds and to determine if further work is required to reduce them to meet the desired scientific goals of the experiments. This presentation will describe SNOLAB's low-background measurement facilities which can be used to directly measure these radioactive backgrounds and to search for new low-background materials which can be used for future detector fabrication.

Speaker: Dr Ian Lawson (SNOLAB)

97 Development and Future Prospects of ZnS Lucas cells

Rn-222 progeny produce unwanted background events in underground rare-event searches including those for dark matter and neutrinoless double beta decay. ZnS(Ag) Lucas cells were used during the SNO experiment to evaluate Radon emanation into light water and continue to be used for ex-situ measurements of Radon concentration in SNO+ and at SNOLAB for materials assays. Support for current and future experiments housed at SNOLAB motivates the development of new Lucas cells to further improve SNOLAB's capabilities for characterizing materials radio-purity with greater precision and sensitivity.

In this presentation, Radon assays are introduced and developments for next-generation Lucas cells will be discussed. Expected topics include novel designs and fabrication methods including ZnS synthesis and doping, Lucas cell efficiency studies, and determination and discrimination of background sources within Lucas cells. Future prospects will be explored including modern materials such as PEEK and PEI thermoplastics, and cryotrapping Radon within Lucas cells.

Speaker: Peter Qin (SNOLAB)

98 Lucas Cell Simulation using Geant4

Receiving low levels of background and measuring trace amounts of remaining radioactivity is very important for particle astrophysics experiments looking for neutrinos or dark matter. The original SNO collaboration developed and has been using Lucas Cells since 1992. They are instrumental to measure the radon concentration in its surrounding water shield as well as its nitrogen cover gas system. Lucas cells are still used by the SNO+ experiment and SNOLAB at large to perform radon emanation measurements for many materials and continue radon assays. These scintillation counters are primarily sensitive to alpha particles, notably those emitted from radon and its progeny. Photomultiplier tubes (PMTs) are then able to detect the light emitted by the silver doped zinc sulfide scintillator, originating from the individual alpha decays. The counting efficiency of these cells measured with alternate means doesn’t match the radon board's efficiency, which indicates the need for further investigation. To assess, I constructed a Lucas Cell model in a Monte-Carlo based physics simulation toolkit, Geant4. The Lucas Cell geometry was formulated using the Geometry Description Markup Language (GDML) and FreeCAD. A radioisotope decay timing model was devised for radon’s relevant alpha emitting progeny. Additionally, the silver doped zinc sulfide scintillator’s optical response was characterized and the Lucas Cell counting efficiency was calculated. The developed simulation framework will help guide further Lucas Cell based radon assay research and enhance the accuracy of current radon measurements. The status and initial results of this project will be presented.

Speaker: Justin Suys (SNOLAB)

99 Vacuum Ultraviolet Stability Measurements of Silicon Photomultipliers at liquid Xenon Temperatures.

Silicon photomultipliers (SiPMs) are single-photon-sensitive devices under consideration for light sensing in noble liquid detectors. One of the experiments considering SiPMs is the neutrinoless double beta decay experiment, nEXO. nEXO plans to search for this decay with 5 tonnes of liquid xenon over a lifetime of 10 years. SiPMs are intended to be placed inside the liquid xenon volume to detect scintillation light. This long operating time necessitates the characterization of the response of nEXO’s SiPM candidates- either VUV4 HPK (Hamamatsu) or FBK HD3, under conditions similar to those of the experiment. While non-ionising radiation (bulk) damage on SiPMs have been well studied, ionising radiation (surface) damage in the top SiO2 layer of SiPMs, which causes surface currents, have not yet been investigated extensively. In this work, we present the study of VUV4 HPK SiPM performance at 165K (liquid xenon temperature) for different Vacuum UltraViolet (VUV) light exposure periods. Specifically, we investigate variations in dark count rates as a result of non-ionizing radiation damage and leakage current variations caused by both ionizing and non-ionizing radiation damage of SiPMs. Latest results will be presented.

Speaker: Riya Rai (McGill University)

100 Modernizing Canada’s radon guidance: Health Canada’s data-driven approaches for radon reduction to address rising radon levels

Radon, a naturally occurring radioactive gas present in our homes, is the leading cause of lung cancer among non-smokers. With nearly 1 in 5 Canadian homes exceedingly Health Canada’s radon guideline level and only 5% of households having tested for radon, radon exposure remains a critical public health issue that is responsible for over 3,000 lung cancer deaths annually in Canada. As part of its National Radon Program, Health Canada consistently reviews and updates national radon risk guidance and resources to adapt to the evolving radon landscape in Canada, ensuring that its actions are evidence-based and effectively mitigate this health risk.

With emerging data indicating growing radon risks for Canadians, Health Canada has been promoting measures to reduce radon exposure and is actively updating key guidance elements. However, due to the various factors affecting radon levels across Canada’s varied geography and climate, identifying data that directly answers key questions about Canadians' radon exposure can be challenging. To address this, the National Radon Program conducts targeted studies to fill data gaps and gather the necessary evidence for informed decision-making.

Health Canada will present its recent progress in various radon reduction strategies, highlighting the data and evidence driving these efforts. This includes research and studies supporting the strengthening of Canada’s building codes and the modernization of its radon testing guidance, most notably with the proliferation of electronic radon monitors in recent years. The presentation will also expand on the existing unknowns in the radon testing of Canadian homes and explore Health Canada’s efforts to answer these remaining questions, focusing on the data and analyses behind policy development. Through these strategies, that look to increase radon testing and mitigation rates, ultimately more Canadians will be protected from the hazards of radon in their homes.

Speaker: Dr Pawel Mekarski (Health Canada)

(DTP) T1-10 Classical and Quantum Gravity | Gravité classique et quantique (DPT)

101 Cryptographic tests of complexity conjectures in holography

In the AdS/CFT correspondence, a spatial subregion of a conformal field theory allows for the recovery of a corresponding subregion of the bulk known as its entanglement wedge. In some cases, an entanglement wedge contains a locally but not globally minimal surface homologous to the CFT subregion, in which case it is said to contain a python's lunch. It has been proposed that python's lunch geometries should be modelled by tensor networks that feature projective operations where the wedge narrows. This model leads to the python's lunch (PL) conjecture, which asserts that reconstructing information from past the locally minimal surface is computationally difficult. In this work, we invoke cryptographic tools pertaining to a primitive known as the conditional disclosure of secrets (CDS) to develop consequences of the projective tensor network model that can be checked directly in AdS/CFT. We argue from the tensor network picture that the mutual information between appropriate CFT subregions is lower bounded linearly by an area difference associated with the geometry of the lunch. Recalling that the mutual information is also computed by bulk extremal surfaces, this gives a checkable geometrical consequence of the tensor network model. We prove weakened versions of this geometrical statement in asymptotically AdS$_{2+1}$ spacetimes satisfying the null energy condition, and confirm it in some example geometries, supporting the tensor network model and by proxy the PL conjecture. On the other hand, we point out a tension between the PL conjecture and a plausible cryptographically inspired lower bound on the mutual information involving the complexity of reconstructing operators inside the lunch; this suggests the existence of protocols for computationally secure CDS requiring unexpectedly small entanglement.

Speaker: Chris Waddell (Perimeter Institute)

102 Unruh in Superposed Spacetimes

It is widely anticipated that a quantized theory of gravity will admit quantum spacetime configurations that are described by a superposition of semiclassical spacetimes. However, in the absence of such a complete theory of quantum gravity, can we learn anything about how such states might behave?
Recent developments led by Foo et al., propose an operational approach to this problem by describing the response of a first-quantized two-level quantum detector coupled to a quantum-controlled superposition of spacetimes. 
Using this operational approach, we investigate what happens to an accelerated detector in such a superposition of spacetimes. We find that previously observed resonance peaks in the response function (occurring at rational values of the quantized spacetime parameter) are accentuated by the acceleration. Moreover, we provide the first explicit analysis of detector thermalization in superposed spacetimes.
If time permits, I will comment on how this extension of the Unruh effect relates to previous work that found non-thermal responses for detectors travelling along superpositions of accelerated trajectories in a fixed spacetime.

Speaker: Everett Patterson (University of Waterloo)

103 Harvesting Mutual Information Behind a Black Hole Horizon

The effect of black holes on entanglement harvesting--the process of extracting entanglement from the quantum vacuum--has been of considerable interest over the past decade. Research involving stationary Unruh-DeWitt (UDW) detectors in a (2+1)-dimensional black hole spacetime (the BTZ black hole) has uncovered phenomena such as entanglement shadows, entanglement amplification through black hole rotation, and differences between bipartite and tripartite entanglement. For a (1+1)-dimensional Schwarzschild black hole, two UDW detectors could harvest entanglement from the scalar quantum vacuum even when separated by an event horizon. The dynamical problem of harvesting entanglement as detectors cross the event horizon is substantially more difficult. To this end, we calculate the mutual information between two UDW detectors coupled to a massless quantum scalar field, with the detectors starting at rest and falling radially into a non-rotating (2+1)-dimensional BTZ black hole. The trajectory of the detectors includes regions where both detectors are switched on outside of the horizon; where one detector is switched on inside of the horizon while the other switches on outside; and where both detectors switch on inside of the horizon. We investigate different black hole masses, detector energy gaps, widths and temporal separations of the detector switching functions, and field boundary conditions. This study is the first to examine correlation harvesting across an event horizon for a black hole spacetime that satisfies Einstein's equations.

Speaker: Sijia Wang (University of Waterloo)

104 Antisymmetric tensor portals to dark matter

Both freeze-in of very weakly coupled dark matter and freeze-out of initially thermalized dark matter from the primordial heat bath provide interesting possibilities for dark matter creation in the early universe. Both scenarios allow for a calculation of baryon-dark matter coupling constants as a function of dark matter mass $m_\chi$, $g=g(m_\chi)$, due to the constraint that freeze-in or freeze-out produce the observed dark matter abundance. Here we compare the resulting coupling constants in the two scenarios if dark matter couples to baryons through an antisymmetric tensor portal. The freeze-in scenario predicts much smaller coupling in agreement with the nonthermalization postulate. We find that the couplings as a function of mass behave very differently in the two scenarios.

Speaker: Alexander Magnus (University of Saskatchewan)

Antisymmetric tensor portals.pdf

105 A pathology in semiclassical gravity

We point out a pathology with a canonical approach to the semiclassical Einstein equation. To be precise, it is shown that such a theory, subjected to the Dirac constraint analysis, renders itself empty, that is, devoid of any nontrivial degrees of freedom. The reason is identified to be the diffeomorphism invariance.

Speaker: Irfan Javed (University of New Brunswick)

106 The geometric trinity of gravity, an introduction to teleparallel and symmetric teleparallel gravity.

The equivalent formulations of gravity will be introduced as General relativity (GR), Teleparallel Equivalent of General Relativity (TEGR), Symmetric Teleparallel Equivalent of General Relativity (STEGR) with a basis toward teleparallel gravity. Mathematical models of theses theories will be introduced with a emphasis on physical differences and mathematical differences. A brief section on the modified theories of f(R), f(T) and f(Q) will be mentioned as a reason of the existence of the equivalent formulations with some thesis results to be shown. The talk is aimed at a senior undergraduate or graduate level for those who have a basic understanding of general relativity

Speaker: Josh Fenwick (University of Saskatchewan)

document.pdf

107 Non-geodesic timelike observers and the ultra-local limit

In the ultralocal limit along timelike geodesics, any geometry is perceived as Bianchi I. It is shown that, in general, this limit does not extend to non-geodesic timelike observers. We discuss exceptions, including particles with variable mass, test particles in Einstein frame scalar-tensor gravity, and self-interacting dark matter.
[Based on R. Saadati, L. Valsan & V. Faraoni 2025, Eur. Phys. J. C 85, 176 (arXiv:2408.00871)]

Speaker: Valerio Faraoni

(DQI) T1-11 | (DIQ)

108 Integrated silicon colour centre devices

Silicon colour centres are an emerging quantum information platform with technological appeal: they emit in or near the optical telecommunications bands, host long coherence spin qubits, and integrate with silicon photonic and electronic circuits for scalable on-chip devices. Potential applications include single-photon sources and quantum repeaters for quantum networks, and resource-state generators for all-optical quantum computers. In particular, the silicon T centre has been identified as a candidate for distributed spin-photon quantum computing and is the focus of ongoing commercialization efforts. In this talk I review the rapid progress in the field of silicon colour centres, including integrated photonic devices with single G, W and T centres, as well as newly discovered or theorized centres contending to be the ultimate silicon emitter, and present recent results with the silicon T centre. Cavity-integrated centres show dramatic Purcell enhancements, enabling faster and more coherent emission. Indistinguishable emission from separate T centre devices has enabled entanglement between T centre processors in separate cryostats, one of only a handful of solid-state quantum platforms to achieve this milestone. New classes of opto-electronic silicon colour centre devices combining optical resonators and PIN junctions enable a host of new spin-photon techniques including electrically-injected single-photon emission, electrical spin initialization, and electrically-triggered remote entanglement schemes. These techniques expand the toolbox of controls available for silicon colour centre quantum processors and networks.

Speaker: Daniel Higginbottom (Simon Fraser University)

109 Optical depth and its relation to warm ensemble based quantum memories and communication rates

The realization of long-distance quantum communication will depend critically on quantum repeater nodes that incorporate robust and scalable quantum memories. To be practical, these memories must meet specific operational requirements. One promising candidate for such devices is the atomic warm vapor system, operating under the regime of electromagnetically induced transparency (EIT). These systems offer ease of implementation and demand minimal experimental infrastructure. A central figure of merit in the performance of atomic quantum memories is the optical depth, which directly influences the efficiency of light-matter interactions. In this work, we simulate and experimentally measure the optical depth performance of an EIT-based quantum memory utilizing a warm atomic vapor cell. We further convert these optical depth and efficiency metrics into projected entanglement distribution rates. Our study assesses the viability of these memory systems within optical quantum repeater architectures, which are vital for establishing robust quantum communication across long distances.

Speaker: Connor Kupchak (Carleton University)

110 Passive relays for continental distance quantum communication

Recent advances in quantum technology have highlighted the need for long-distance quantum communication in order to enable technologies such as quantum key distribution, very-long-baseline interferometry, and distributed quantum computing. Fiber attenuation limits optical fiber links to hundreds of kilometers, while present day satellite links are limited to line-of-sight connections of approximately 1200km. We propose a satellite configuration using a satellite-borne entangled photon source with passive relays placed in trailing orbits. With realistic assumptions on ground station telescopes, lenses, and performance of entangled photon sources, we show that this scheme is able to bridge the continental distances for quantum communication across Canada and intercontinental distances linking North America and Europe. This represents a method of immediately providing entanglement distribution across many thousands of kilometers, a key step towards a global quantum internet.

Speaker: Wilson Wu (Simon Fraser University)

111 Surface Ion Trap System for Barium-Based Quantum Information Processing

We present our progress in developing a surface ion trap system designed for quantum information processing with barium ions. Ba⁺ ions are among the most promising qubit candidates due to their long-lived quantum states and visible-wavelength optical transitions, allowing the use of commercial optics and waveguide-based modulators for individual qubit control. Our system features a Sandia National Lab-fabricated surface ion trap with 94 controllable DC electrode channels enabling precise control of the confining potential. The trap is centrally mounted in the vacuum chamber, departing from conventional flange-mounted designs to maximize optical access while maintaining ultra-high vacuum conditions (3×10⁻¹¹ mbar). We have developed specialized methods to prepare both natural abundance and radioactive ¹³³Ba atomic sources and implemented a modular fiber-coupled optical system where multiple wavelengths are combined and delivered via custom designed boards. Our architecture accommodates individual addressing of multiple ion qubits with negligible intensity crosstalk at 1e-4 level. As part of the Open Quantum Design initiative, this system will integrate with a full-stack control system, enabling remote access to the system at various levels of abstraction.

Speaker: Akbar Jahangiri Jozani (University of Waterloo)

112 Droplet creation in the walking droplet pilot wave system and in Bose-Einstein condensates: walking droplets, vortex molecules, and Faraday instability

Condensed matter systems such as superfluids can simulate phenomena in every major area of physics, from gravitational to cosmological to high-energy physics, including an analog for quark confinement known as “vortex molecules” (Eto, Ikeno & Nitta, 2020). On the other hand, in the last twenty years the field of Hydrodynamic Quantum Analogs (HQA), which studies the walking droplet pilot wave system, has provided deep insights into the nature of quantum behaviours. This field was reviewed in 2021, including longstanding misinterpretation of Bell's work (Bush & Oza, 2021).

Walking droplets exhibit uncanny analogs for many quantum effects of electrons and photons, such as diffraction through slits, tunnelling, entanglement, multi-modal statistics, quantized orbits, Landau levels and Zeeman splitting in a magnetic field, spin states, and spin-spin correlations. Although their behaviour is most like de Broglie's original (and never completed) double solution theory, walking droplets’ behaviour is unique, described by a hydrodynamic pilot wave theory in which a chaotic, non-Markovian dynamics – dynamics with a memory – plays a key role.

In this system, the bath is vertically driven, causing Faraday waves to break out on the surface at large enough acceleration. The droplets’ quantum-like behaviours are strongest in what is known as the “high memory” regime, near the Faraday threshold, where the effects of viscous damping are mitigated and the pilot-wave is most long-lived. At accelerations far above the Faraday threshold, waves break and droplets are created.

We investigate droplet creation in a Bose-Einstein condensate (BEC) system hosting vortex molecules, a Rabi-coupled system of two different hyperfine spin states. Droplet creation has been shown numerically for a BEC of two immiscible components driven towards each other by an oscillating force, with droplets generated at their interface along with quantum vortices. We expect a similar result in the Rabi-coupled case, where the Rabi coupling itself serves as the periodic driving.

Speaker: Vicky Howse (University of Saskatchewan)

113 The Relativistic Origin of Quantum Indeterminacy

Problem: Indeterminacy is a foundational principle of quantum physics. The fact that pure quantum systems possess properties with no definite single sharp value is a fundamental expression of this quantum indeterminacy. For example, an electron within an atom possesses no definite value of linear momentum. Although, in isolation, indeterminacy is not inherently problematic, there is arguably an inconsistency between quantum indeterminacy and the presumed definiteness of classical relativistic spacetime. We may ask: How is it that indeterminate quantum matter exists within a determinate spacetime? Mariani (1) discusses potential epistemic, semantic and ontological sources of quantum indeterminacy, while Gisin (2) and co-workers have proposed a new principle of "finiteness of information density" as a source of indeterminacy, related to the ontological status of the infinitely precise real numbers.
Aims: The aims of this work are to: a) to show that the source of quantum indeterminacy currently stands as an open question; b) to show that there is a fundamental (albeit latent) source of indeterminism arising from the principle of relativity; c) to show that the quantum measurement process has all the properties predicted to manifest this latent indeterminacy.
Argument in outline: Within the framework of special relativity, for an ensemble of coexisting inertial observers, there is irreconcilable disagreement on measurements of spatial and temporal intervals. For a classical system, observers remain independent so can “agree to disagree”, and the conflict is benign and essentially just epistemic. However, in the corresponding quantum scenario (with each observer now part of one momentum superposition) disagreement at the observer level entails indeterminacy for the system as a whole. The argument turns on issues of spacetime ontology, quantum interpretation and quantum reference frames.
Discussion: In summary, it is proposed that long familiar relativistic disagreements emerge as the fundamental source of quantum indeterminacy. This is part of a program on a many-spaces quantum spacetime (Sharp, 2024).

References:
(1) Mariani, The Determinacy Problem in Quantum Mechanics. Foundations of Physics (2024) 54:73
(2) Del Santo and Gisin 2021, The relativity of indeterminacy arXiv:2101.04134v1).
(3) A Universe of Spaces (Amazon) J.C. Sharp (2024)

Speaker: Prof. Jonathan Sharp (University of Alberta)

(DPMB) T1-12

114 New insights into thermal switching kinetics of molecular photoswitches revealed by protonation and metal coordination

Azobenzene photoswitches are an indispensable tool in light-responsive materials design. When irradiated by light, azobenzenes undergo a reversible trans-cis photoisomerization about the azo bond (N=N), a robust process used to photocontrol the properties of various materials, including metal organic frameworks, chemical sensors, biomimetic coatings, and liquid crystals. The isomerization process however is also thermally reversible. Depending on photoswitch design and environmental conditions, thermal lifetimes can vary from nanoseconds to years, yet the precise engineering of azobenzene-based materials depends strongly on exquisite control of this lifetime. Protonation and metal coordination are emerging as tools to control the mechanism and lifetime of thermal isomerization, however a complete understanding of their diverse effects is still lacking.

In this study, azobenzene was modified with a bidentate ligand to create the photoswitch HPAS, which possesses both pH responsivity and metal coordination abilities. Using density functional theory, complete active space self-consistent field, and spin-flip quantum mechanical methods, we explored the effect of protonation and Cu$^{2+}$ coordination on the thermal isomerization kinetics of HPAS. Protonation studies revealed an equilibrium exclusively for the cis isomer involving proton transfer to the azo group and significant weakening of the double bond. We show, for the first time, that rapid rotation about the ruptured azo bond involves two torsional degrees of freedom and an ammonia-like inversion process. Due to the unpaired electron of Cu$^{2+}$, novel consequences on intersystem crossing along the rotation pathway are discussed.

Speaker: Coral Hillel (York University)

(DASP) T1-2 Ionosphere, Thermosphere, and Radio Propagation | Ionosphère, thermosphère et propagation radioélectrique (DPAE)

Convener: David Themens (University of New Brunswick)

115 Advancing Research through Modular Instrumentation

Characterization and calibration of measurement instruments is vital to meaningful and traceable data acquisition. However, the complexity of commonly involved systems has long surpassed the scope of what a single person is able to develop, operate, and maintain on their own. In addition, academic interests evolve and regularly require experimental setups to be reconfigured based on lessons learned in the field. Budgetary constraints, diversity in project scopes, short-term measurement campaigns, and student turnover place further demands on the operation and maintenance of instrumentation in an academic environment.

This presentation shares insights and experience from the development of the modular measurement platform ‘sanimut’ to its operation in the Canadian Arctic today. While initial considerations were dominated by budget and supply chain management, a variety of tools and methods has emerged and continues to boost development efficiency, stimulates new projects, and fosters student involvement. The modular circuit board designs, simulation of gateware and analog circuitry, as well as application interface resources continue to contribute to experiment design, parametric studies, as well as ease of maintenance in the field. The system is segmented into individual building blocks with unique and comprehensible characteristics. This enables independent optimization, incremental updates, and partial reconfiguration of existing instruments. It facilitates tailoring contributions and training that align personnel experience with project scope. While the examples are specific, the discussed methodology and conclusions are general and are relevant to ionospheric observation and beyond.

Speakers: Mr Philippe Trottier (University of New Brunswick), Prof. Torsten Reuschel (University of New Brunswick)

116 Improved ionospheric observations of E-Region radar aurora through calibration of the ICEBEAR radar

The high resolution ICEBEAR (Ionospheric Continuous-wave E-region Bistatic Experimental Auroral Radar) is a low-elevation radar designed primarily to observe E-region radar aurora and meteor trails. Having accurate altitude radar observations is critical for a better physical understanding of the height dependence of the plasma processes and irregularities associated with the radar aurora. ICEBEAR relies on interferometric processing to precisely locate echoes geographically within a wide field-of-view. This interferometry is performed using the phase of the received signal on 10 independent receiving antenna paths, meaning that phase calibration of the radar receiver antenna array is of utmost importance for confident and accurate measurements. In addition to observing radar aurora and meteor trails, ICEBEAR regularly receives echoes scattered from aircraft, the location of which are known with a high degree of confidence via independent means. In this talk, I will explain how I utilize the aircraft echoes to perform high-quality ICEBEAR receiver phase calibrations, ensuring the accuracy of ICEBEAR measurements for new and enhanced ionospheric understanding.

Speaker: Remington Rohel (University of Saskatchewan)

117 Near Real-Time Riometer Data Processing

Riometers provide passive instrumentation for monitoring and analyzing changes to ionospheric absorption. The relative nature of riometer measurements, and their sensitivity to noise, pose challenges for their use in calculation of near real-time absorption. To this end, methods for automatically cleaning, filtering, and processing riometer data from the NRCan riometer network have been developed. These algorithms flag likely periods of absorption and radio noise, which enables the near real-time calculation of riometer quiet day curves and local ionospheric absorption. To demonstrate the method’s ability to automatically calculate absorption, its performance is evaluated during absorption events, using data from the NRCan riometer network. Periods which were excluded from quiet day curve calculation due to heightened noise or suspected periods of absorption were found to have higher deviations and a poorer fit to calculated quiet day curve values than quiet time periods, indicating the algorithm is correctly identifying periods for exclusion from quiet-day curve calculation.

Speaker: Kyle Reiter (Natural Resources Canada)

118 The many discoveries of the ICEBEAR-3D E-region coherent radar

The Ionospheric Continuous-wave E-region Bistatic Experimental Auroral Radar (ICEBEAR) is a fully digital software defined radio (SDR) high-resolution 49.5~MHz VHF coherent E-region radar with an auroral zone field-of-view situated in western Canada (58N, 106W geographic). First light was in 2017, but in 2019 the final design of ICEBEAR was implemented with the re-configuration of the ICEBEAR receiver antenna array into a non-uniform co-planar T-shaped double interferometer layout. Applying highly advance tailored aperture synthesis radar imaging techniques, radar echoes can be unambiguously located within the ICEBEAR-3D field-of-view with a nominal resolution of 1--3~km in 3-dimensions (range, azimuth, elevation). Both the scientific and technical research discoveries of ICEBEAR-3D has been many and varied, the former being highly enhanced by the highly advanced technical abilities of ICEBEAR-3D. This presentation will survey the many varied technical and scientific discoveries of this unique E-region coherent radar.

Speaker: Glenn Hussey (University of Saskatchewan)

119 An analysis of WWV’s 10 MHz signal received in New Jersey

This study investigates the impact of ionospheric variability on High Frequency (HF; 3-30 MHz) skywave propagation, a critical aspect of long-range radio communication. Using a dedicated HamSCI Grape V1 low-IF receiver (K2MFF) at the New Jersey Institute of Technology (NJIT) in Newark, New Jersey, we analyzed long-term Doppler residual measurements of the 10 MHz WWV signal from Fort Collins, Colorado. The observations reveal a strong correlation between stable daytime propagation and a Cauchy distribution of Doppler residuals, while sporadic nighttime conditions align more with a combination of exponential power and log-normal statistics. This pattern persisted, except during periods of atypical solar irradiance, such as solar flares and eclipses. We compare these findings with numerical raytracing simulations using an IRI ionosphere model, allowing for the visualization of the signal's ray path and the geolocation of the ionospheric altitudes (100-400 km) responsible for observed features. Raytracing attributed daytime signal stability to multi-hop mode superposition, while nighttime oscillations—hypothesized to be traveling ionospheric disturbances (TIDs)—were linked to ionospheric variability under 1-hop propagation. By examining diurnal variations in Doppler residuals, this work provides HF operators with a better understanding of ionospheric dynamics and their impact on HF communication, ultimately contributing to improved prediction of propagation conditions and more effective use of the HF spectrum. Additionally, this work provides a foundation for interpreting real-time propagation data and understanding the effects of solar activity and ionospheric variations on signal quality and reliability for amateur radio communication.

Speaker: Gareth Perry (New Jersey Institute of Technology)

120 Doppler shift of transionospheric HF radio waves

When HF radio waves travel through a dispersive medium such as the ionosphere, the refractive index varies along the wave path from the transmitter to the satellite receiver. The electron density profile along the path of the radio waves is used as input to a raytracing model to assess the effect of the refractive index on the radio wave. Using the radio receiver instrument (RRI) on the e-POP/Swarm-E satellite, the Doppler shift is used to verify the methodology underlying the model. The measured Doppler shift is observed to be lower than expected for the free space case.

Speaker: Donald Danskin (University of Saskatchewan)

(DAMOPC) T1-3 Analytical Methods - Ions and Radiation | Méthodes analytiques - ions et radiations (DPAMPC)

121 Interatomic Coulombic decay in ion-impact collisions: a theoretical perspective

Interatomic Coulombic decay (ICD) is a non-local, radiationless de-excitation process that has garnered widespread interest owing to its ubiquity, its intriguing nature, and its relevance for applications. Predicted in 1997 [1], it was first observed in photoexcited neon clusters and has, over the course of the years, been demonstrated in a large number of systems, including atomic and molecular clusters, liquids, and quantum dots, and in different variants [2]. In its simplest form, ICD is initiated by the removal of an electron from an inner valence shell, provided the excited state created has insufficient energy for a fast Auger-Meitner decay process. In an isolated atom, such a state decays by photon emission, but in a cluster the excitation energy can be transferred to a neighbour where it is used to remove an electron. The latter is the reason for the applied interest in ICD, since (low-energy) electrons are able molecular bond breakers, i.e., adept at inflicting damage to surrounding matter.

In this talk, I will focus on ion-impact-induced ICD in ostensibly simple systems such as neon and argon dimers. I will provide an overview of the experimental evidence for ICD in theses systems and discuss our recent theoretical work [3] aimed at shedding light on the existing data and providing clues for worthwhile future studies.

[1] L. S. Cederbaum et al., Phys. Rev. Lett. 79, 4778 (1997).
[2] T. Jahnke et al., Chem. Rev. 120, 11295 (2020).
[3] T. Kirchner, J. Phys. B 54, 205201 (2021); D. Starko and T. Kirchner, submitted.

Speaker: Tom Kirchner (York University)

122 Trapped-ion quantum simulations with mid-circuit measurements and resets

Trapped ions are an ideal platform for the quantum simulation of various models of interacting quantum matter. In this talk, I will give an overview of quantum simulations with trapped ions, where coherent time evolution competes with incoherent operations, such as the measurement and reset of the quantum state of only a part of the system. Such ‘mid-circuit’ measurement and reset operations can lead to the creation of non-trivial quantum phases of matter that cannot be obtained through coherent evolution alone. I will describe our group's efforts in building the toolbox to realize such quantum simulations, including the demonstration of in situ measurement of a trapped ion qubit without accidentally measuring its neighbors. Our work involves exquisite control of laser radiation targeted at individual ions through programmable holography, as well as using the ion itself as a sensor for aberrations. Measurement-driven quantum phases are generally intractable on classical computers, underscoring the importance of using quantum simulators to explore such phases.

Speaker: Kazi Rajibul Islam (University of Waterloo)

123 Analytical Models for Crossing-Beam Backward Stimulated Brillouin Scattering Amplifiers

Backward Stimulated Brillouin Scattering (SBS) in gases offers a promising means to amplify short laser pulses to high energies while avoiding damage to the gain medium that solid state amplifiers experience. To optimize the yield of such amplifiers, modeling codes are required. In the high-pressure regime hydrodynamic theory using the Navier-Stokes model has been shown to agree with experimental results [1] while at lower pressures the behaviour of SBS can be predicted with kinetic theories using the Boltzmann-BGK model [2]. While these models can predict ideal gain coefficients, a more complete numerical calculation is required to include the effects of spatial and temporal non-uniformities in the beams. Additionally, in non-colinear SBS amplification systems, the pump/probe beams must pass through each other at small angles which these models do not consider. To verify the accuracy of any numerical calculations, a number of exact analytic cases are needed for comparison. We have developed several simple analytical models of SBS amplification for pulses with flat top and linear gradient spatial profiles at small crossing angles in the absence of pump depletion. These models have been extended to include pump depletion by incorporating the Frantz-Nodvik saturated gain equations [3]. These models are compatible with both the high and low pressure SBS regimes. The analytic models were then used to verify the results of a full numerical simulation in the low-pressure regime, which in turn was used to calculate the gain coefficients from experimental measurements. Further details of these models and examples of their application will be presented.

[1] E. E. Hagenlocker et al., Appl. Phys. Lett. Vol. 7, No. 9, pp. 236-238 (1965)
[2] V. S. Averbakh et al., Sov. J. Quant. Electron. Vol. 5, No. 10, pp. 1201-1206 (1975)
[3] L.M. Frantz et al., J. Appl. Phys. 24, 2346 (1963)

Speaker: John Gjevre (University of Alberta)

124 Portable Anemia analysis using photovoltaic devices: Precision on the go!

Anemia, characterized by reduced Hemoglobin (Hb) or red blood cell count, affects a quarter of the world’s population by diminishing the body’s ability to transport oxygen. Quick diagnostic time is of the essence for this preventable and curable disease. The state-of-the-art anemia diagnoses are Automated Hematology Analyzers. Their high cost and long diagnostic time are the price for their accuracy in laboratory and clinical settings, making them inaccessible to third-world countries and remote locations. This study explores the potential of photovoltaic devices (PVs) as a cost-effective alternative for Hb sensing.

PVs create a repeatable electrical signal upon light absorption, with the short-circuit current (Isc) reflecting the change in illumination. Their durability and low cost make them suitable for point-of-care applications.

RGB LEDs illuminated Dye-sensitized solar cells (DSSCs) and Silicon-based PVs, measuring Isc responses to varying bovine Hb concentrations (0.1–1 mM). While lower than physiological levels, the selected concentration range allows for sensitivity evaluation within cost and solubility constraints. RGB allows for broad-spectrum wavelength analysis at a lower cost than monochromatic light, keeping the diagnostic tool affordable.

Preliminary results show consistent Isc at specific concentrations of Hb, a negative correlation between Isc and concentration, and a positive correlation between concentration and absorbance, which indicates that the increase in concentration reduces the available light for photocurrent generation. However, the current experiment lacks Hb specificity. Future steps will address this by functionalizing glass slides with a ligand to bind Hb and enhance specificity, allowing the real-time Hb concentration analysis for POC diagnostics. Our approach aims to deliver a reliable, low-cost diagnostic tool, addressing the global need for accessible healthcare.

Reference: Meng Z, Tayyab M, Lin Z, Raji H, Javanmard M. A Smartphone-Based Disposable Hemoglobin Sensor Based on Colorimetric Analysis. Sensors (Basel). 2022 Dec 30;23(1):394. doi: 10.3390/s23010394. PMID: 36616992.

Speaker: Sergio Majluf Suárez (Nano-imaging and Spectroscopy Laboratory, Faculty of Science, University of Ontario Institute of Technology)

11:45 Discussion / Networking

(DCMMP) T1-4 Quantum and Soft Materials | Matériaux quantiques et mous (DPMCM)

125 Characterizing Neuromorphic Nanowire Networks via a Unified Computational Framework

Neuromorphic systems are entities that have abilities that mimic the way the human brain works, one of the most complex systems that we know of. Randomly self-assembled nanowire networks (NWNs) are dynamical systems which have demonstrated brain-like abilities such as remembering stimulus and performing in-situ computations. While there are many models for NWNs, ones which have memristive junctions between nanowires have shown great potential for neuromorphic applications. These memristive junctions are similar to resistive junctions but have memory capabilities and an adaptive resistance that changes with response to inputs, giving them similarity to neurosynapses. The junctions are formed at the nanoscale in which ionic drift-diffusion effects, as well as quantum effects, can be modelled using effective dynamical differential equations describing the conductance evolution and charge mobility within the inner-wire touching points. Since various models have been proposed to capture the largely complex and abstract nature of memristive junctions, we developed a novel computational framework to simulate and analyze NWNs in a more unified manner. Implemented in the Python programming language, our framework allows for the static and dynamic analysis of NWNs under arbitrary memristive models. This framework acts as a foundation for more complex scenarios, such as reservoir computing, information processing, or data classification. Furthermore, we are able to perform large-scale analysis by simulating thousands of NWNs to extract data from. This gives our analysis a unique edge as we can now not only perform these simulations coherently and systematically but also perform them in large batches for better statistical analysis, more accurate predictions, and improved understanding of ensemble behaviours. Effectively, this framework allows for the creation, simulation, and analysis of memristive-based NWNs so that the network simulation pipeline need not be recreated for each new dynamical junction model. It will offer, and play a key role in, exploration and testing of advanced NWN scenarios for neuromorphic computing applications.

Speaker: Marcus Kasdorf

126 Exploring Collapsed Single-Walled Carbon Nanotubes as Quasi-1D Electronic Systems

The collapse of large-diameter, chiral, single-walled carbon nanotubes (SWCNTs) can form bilayer-like ribbons, characterized by quasi-one-dimensional (1D) moiré superlattices and exotic electronic behavior. Using analytical treatments of diameter, chirality, and moiré twist angles, we demonstrate that the moiré wavelength approximates the width of the collapsed SWCNT, producing quasi-1D moiré potentials along its longitudinal axis when the chiral indices are fixed at (n, m=1). This geometry departs from standard two-dimensional twisted bilayer systems by confining the moiré pattern to one dimension. Changes in band structure upon collapse are explored via tight-binding Hamiltonians and Bloch wavefunctions, substantiating that numerical or iterative methods are required for precise predictions. However, by projecting the low-energy Dirac Hamiltonian near the graphene K-point onto the tube’s longitudinal axis, we obtain a tractable quasi-1D Hamiltonian that yields approximate insight into the emergent bands when truncated and diagonalized. ​​This projection is akin to slicing a 2D (planar) twisted bilayer graphene sheet into a strip only one moiré unit wide, yielding a quasi-1D ribbon. Toy model calculations employing this slicing approach were carried out to validate the method, successfully reproducing the band structures anticipated for monolayer nanoribbons. These findings establish a foundation for understanding moiré-induced electronic properties in quasi-1D systems, opening pathways for theoretical and experimental exploration of novel low-dimensional quantum phenomena.

Speaker: Zachary Ireland (University of Toronto)

127 Ising Spin-Orbit Coupling and Electronic Band Structures of t2g Electrons at Charged Ferroelectric Domain Walls

The interplay between electron charge, spin, and ferroelectric polarization is under-explored for conducting ferroelectric domain walls. We investigated the electronic band structures of $t_{2g}$ electrons, confined to charged 90$^\circ$ domain walls in barium titanate ($BaTiO_3$), a prototypical perovskite ferroelectric. A key novel aspect of our study is the explicit inclusion of both orbital and spin degrees of freedom in the Hamiltonian. This leads to an Ising-type spin-orbit coupling. We constructed a tight-binding model(TBM) for $t_2g$ electrons that is constrained by symmetries of the domain wall, including time-reversal, mirror, and rotational symmetries. First-principles density functional theory (DFT) calculations were performed to extract the tight binding parameters. Our findings offer new insights into spin-orbit interactions at ferroelectric domain walls and open avenues for their potential use in next-generation electronic and spintronic devices

Speaker: Ms Maryam Nasir

Abstract.pdf

128 DFT studies of the effect of magnetic ordering and Hubbard U on the properties of UN

Metallic ceramic fuels, for example, UN, are very interesting materials as their thermal conductivity remains high even at very high temperatures due to significant electronic heat transport. They are important because urania fuel, which is used in conventional nuclear reactors, is not the optimum option for some designs of new-generation reactors due to its low thermal conductivity. U-density (34.2 atoms/nm3) in UN is higher than in UO2 (24.47 atoms/nm3); therefore, it is more economical and suitable for implementation as a lower enrichment (LEU) fuel.

We have investigated the effect of magnetic ordering and Hubbard U (HU) on electronic transport and elastic properties of UN using first-principles methods. The generalized gradient approximation (GGA) of the Perdew, Burke, and Hubbard U, implemented in VASP code, and the new BoltzTrap2 code were used. Although we found that the free energy is lower for ferromagnetic ordering than non-magnetic or antiferromagnetic state, only antiferromagnetic ordering with GGA + HU = 3.5 eV predicted the electronic transport of UN in agreement with the experiment.

Speaker: Dr Barbara Szpunar (University of Saskatchewan)

129 Capillary-Driven Coalescence of Bidisperse Particle Rafts with Tunable Cohesion

The coalescence of liquid drops is a well-studied and ubiquitous natural phenomenon central to many industrial processes. We study the physics of a granular analogue of this process through the coalescence of particle rafts in which individual particle rearrangements can be directly observed. In the experiments, a pair of two-dimensional bidisperse rafts of microscopic oil droplets are released and coalesce, driven by capillary forces. A tunable cohesive force between particles mediates the large-scale relaxation of the structure. Varying the strength of cohesion, we investigate the geometry and dynamics of this raft coalescence process.

Speaker: Cameron Burns (McMaster Univ.)

130 Memory formation using local deformations in a disordered aggregate of droplets

The formation of memory in jammed, disordered systems through cyclic global deformation has been observed in both simulations and experiments in recent years. Using a novel experimental approach, we demonstrate that local deformations can also drive memory formation. In our setup, we create a bidisperse aggregate of frictionless, cohesive oil droplets confined to a 2D coral. A single intruding ferrofluid droplet is introduced and manipulated with a magnet. As this ferrofluid intruder moves in a uniaxial, oscillatory manner, the aggregate rearranges and encodes the memory of the oscillation's amplitude. This stored amplitude can be recovered by probing the system after memory encoding. We observe that the aggregate's response is trained over several training cycles, with larger deformation amplitudes requiring more cycles to encode the memory.

Speaker: Marzuk Gazi

(DGEP) T1-5 Special Session: Improv for Culture Change Workshop | Session spéciale : Atelier d'improvisation (DEGP)

Interactions are fundamental to physics, be they physical forces between systems or social dynamics between humans. Let’s create a camaraderie-filled laboratory to uncover biases and test assumptions underlying our day-to-day interactions with each other and with physics. Join us to apply the tools and techniques of improvisational theatre (improv) in this interactive session. We will playfully experiment with what we can learn from engaging in improv exercises to build healthier physics learning and research communities. Come ready to engage!

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Les interactions sont fondamentales en physique, qu’il s’agisse de forces physiques entre systèmes ou de dynamiques sociales entre humains. Créons un laboratoire rempli de camaraderie pour découvrir les préjugés et tester les hypothèses qui sous-tendent nos interactions quotidiennes les uns avec les autres et avec la physique. Rejoignez-nous pour appliquer les outils et les techniques de l’improvisation théâtrale (improv) au cours de cette session interactive. Nous expérimenterons de manière ludique ce que nous pouvons apprendre en nous engageant dans des exercices d’improvisation pour construire des communautés d’apprentissage et de recherche en physique plus saines. Attendez-vous à du plaisir !

131 Improv-phys-ation | Atelier d'improvisation

Interactions are fundamental to physics, be they physical forces between systems or social dynamics between humans. Let’s create a camaraderie-filled laboratory to uncover biases and test assumptions underlying our day-to-day interactions with each other and with physics. Join us to apply the tools and techniques of improvisational theatre (improv) in this interactive session. We will playfully experiment with what we can learn from engaging in improv exercises to build healthier physics learning and research communities.

Resources/inspirations:

Specta(c)tor Theatre Forum
improv in physics education: Improv-phys-ation
improv in higher ed: Yes, And Higher Ed Network
improv/play for cultural change: Global Play Brigade

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Les interactions sont fondamentales en physique, qu’il s’agisse de forces physiques entre systèmes ou de dynamiques sociales entre humains. Créons un laboratoire rempli de camaraderie pour découvrir les préjugés et tester les hypothèses qui sous-tendent nos interactions quotidiennes les uns avec les autres et avec la physique. Rejoignez-nous pour appliquer les outils et les techniques de l’improvisation théâtrale (improv) au cours de cette session interactive. Nous expérimenterons de manière ludique ce que nous pouvons apprendre en nous engageant dans des exercices d’improvisation pour construire des communautés d’apprentissage et de recherche en physique plus saines.

Ressources/inspirations :

Specta(c)tor Theatre Forum
improv dans l’éducation de la physique : Improv-phys-ation
improv dans l’éducation dans les études supérieure : Yes, And Higher Ed Network
improvisation/jeu pour le changement culturel : Global Play Brigade

Speaker: Carolyn Sealfon (Minerva University)

(DNP) T1-6 Hadrons | Hadrons (DPN)

132 The Barrel Imaging Calorimeter for the ePIC Experiment at EIC

The Electron-Ion Collider (EIC) is a facility being constructed at Brookhaven National Lab that will enable investigation of gluon interactions and structure in nucleons and nuclei using polarized beams of electrons and atomic nuclei. The Electron-Proton/Ion Collider (ePIC) experiment will be the first to run at EIC. The ePIC detector will be a barrel-shaped hermetic detector comprised of many specialized subsystems (Cherenkov detectors, tracking systems, calorimeters, and time-of-flight detectors), each handling various facets of particle detection and identification in different spatial regions. ePIC collaborators at the University of Regina primarily contribute to the design, simulation, and testing of the Barrel Imaging Calorimeter (BIC), the electromagnetic calorimeter in the barrel region of the detector. This subsystem must accurately gauge the energy and paths of photons passing through it while providing precise measurements of other electromagnetic particle energy and shower profiles in order to distinguish electrons from other particles, such as background pions in deep inelastic scattering processes at high Q$^2$.

I will be discussing the design and projected capabilities of the BIC, a hybrid detector system that combines traditional calorimetry using scintillating fibers embedded in lead with imaging calorimetry based on AstroPix chips (low-power monolithic active pixel sensors). Progress in prototyping, testing, and signal readout integration will also be presented.

Speaker: Tegan Beattie

133 Measurement of Charged Pion Form Factor at Jefferson Lab

One of the most challenging goals in modern physics is to understand hadronic structure, as properties of constituent quarks and gluons (e.g. spin, mass) do not explicitly add up to the properties of hadrons. The pion ($\pi$-meson) is the lightest quark system and its properties are deeply linked to the understanding of how quarks are confined in hadronic matter. The pion form factor ($F_{\pi}$) is an important observable and can be measured by studying the exclusive pion electro-production reaction $p(e,e' \pi^+)n$. The Pion-LT experiment was performed to measure the $F_{\pi}$ at high $Q^2$ over a wide kinematic range at the Thomas Jefferson National Accelerator Facility (JLab) located in Newport News, Virginia, USA. This experiment seeks to measure longitudinal cross-section ($\sigma_L$) and transverse cross-section ($\sigma_T$) using the unique Rosenbluth LT-separation technique, in order to extract $F_{\pi}$ precisely. In this talk, I will discuss the current status of Pion form factor measurements and the Rosenbluth LT-separation technique performed at Jefferson Lab on behalf of the PionLT collaboration.

Speaker: Mr Muhammad Junaid (University of Regina)

134 A New Angle Into the Proton: Backward-Angle Meson Electroproduction

Despite being a core component of visible matter, the structure of protons and neutrons is still incompletely understood. Due to the limitations of QCD in the non-perturbative regime, hadronic structure must be determined via experiment. The KaonLT experiment at Jefferson Lab Hall C measures Deep Exclusive Meson Production (DEMP) reactions in order to study the interior structure of the proton and the nature of the strong force. This work will analyze a unique reaction in the KaonLT data known as the u-channel, or backward-angle meson electroproduction. Backward-angle reactions offer unique information which is complementary to standard forward-angle DEMP, for example access to the $qqqq\bar{q}$ part of the proton wavefunction and Transition Distribution Amplitudes (TDAs). This talk will present an overview of the novel opportunities offered by u-channel physics, the current progress on a u-channel analysis of the KaonLT data, and the possibilities for future u-channel measurements at Jefferson Lab and the Electron-Ion Collider.

Speaker: Alicia Postuma (University of Regina)

135 Shim coils and their importance in measuring the neutron electric dipole moment for the TUCAN EDM experiment

Precise measurements of the neutron electric dipole moment (EDM) could result in a discovery of a violation of particle-antiparticle symmetry, and of new physics beyond the standard model.
The TRIUMF Ultracold Advanced Neutron (TUCAN) collaboration is preparing an experiment to measure the neutron EDM with an accuracy of $1\times10^{-27}$~$e$cm, a factor of 10 better than the world's previous best, published in 2020. Neutron motion in the EDM cells in the presence of magnetic field inhomogeneity could results in a false neutron EDM signal. Shim coils are used to characterize and reduce magnetic field inhomogeneities. The shim coils must make the field inside the EDM measurement cells very homogeneous, $\sigma(B_z)<40~{\rm pT}$ in field of $B_z=1~\mu{\rm T}$, in order to meet the requirements of the experiment. I will present my design studies of a shim coil system for the TUCAN EDM experiment, which is based on square coils placed on the walls of the magnetically shielded room (MSR) surrounding the EDM cells. I will also report on the construction of the coils, which was completed in August 2024. The coils were installed inside the MSR in early 2025. I will present results from MSR magnetic field mapping that will begin May 2025, as a part of the commissioning of the magnetically shielded room and precision atomic magnetometer systems. I will further present our plans for the operation of the coil system.

Speaker: Modeste Katotoka (The University of Winnipeg)

136 Study of the b1(1235) meson decay via the omega+pi^0 channel at GlueX

One of the fundamental objectives of hadron physics is to explore how quark and gluon interactions shape the hadron spectrum as described by Quantum Chromodynamics (QCD). The GlueX experiment at Jefferson Lab plays a key role in this global spectroscopy program by utilizing an 8–9 GeV beam of linearly polarized photons to investigate meson production. By focusing on the light-quark sector, this experiment provides a unique opportunity to study hybrid mesons that may exhibit exotic $J^{PC}$ quantum numbers through photoproduction processes. Recent lattice QCD calculations predict that the lightest exotic $\pi_1(1600)$ decays primarily to a $b_1 \to \omega\pi^0$ system and can be experimentally accessed through the dominant decay $b_1 \to \omega\pi^0$. The GlueX experiment provides access to this process through photoproduction channels such as $\gamma p \to p b_1\pi^0$ and $\gamma p \to b_1 p$, where the axial-vector $b_1(1235)$ meson decays to $\omega\pi^0$. To better understand this decay mechanism, partial wave analysis has been successfully employed to extract the D/S wave ratio, which is essential for validating Lattice QCD predictions regarding the couplings of this resonance. Next steps involve handling ambiguities in the extracted amplitudes of the partial waves as well as examining the combinatorics of the final state particles to ensure that their effects do not result in spurious results.

Speaker: Mr Harsimran Singh (University of Regina)

CAP_Abstract_2025.pdf

137 Probing Hadron Structure through $e ~ + ~ p ~ \to ~ e^{'} ~ + ~ \pi^{+} ~ + ~ \Delta^{0}$ reaction at Jefferson Lab

The internal structure of hadrons is incompletely understood, as the intrinsic properties of hadrons (e.g. mass, spin) cannot yet be fully understood within a QCD framework. Generalized Parton Distributions (GPDs) provide information about the three dimensional structure of hadrons. The pion is a good candidate for hadron structure studies, due to its relatively simple structure and its experimental accessibility. Experimental Hall C at Jefferson Lab is a unique facility that can host high precision studies of exclusive pion electroproduction reactions. The cross-section of this reaction is dictated by the longitudinal and transverse polarizations of the virtual photon. Considering the recoil system in such a reaction, the ground state nucleon in the $p(e,e^{'} \pi^{+})n$ reaction has been studied in detail but little is known about the nucleon-to-resonance ($N \to \Delta$) transition reaction $p(e,e^{'} \pi^{+})\Delta^{0}$. This reaction provides access to the transition GPDs. The 12 GeV upgrade at Jefferson Lab provides a unique opportunity to study the higher resonance of pion electroproduction reaction $p(e,e^{'} \pi^{+})\Delta^{0}$ at wide range of kinematics ($Q^{2}, ~ W$ and $-t$). This talk will present the first measurement of the beam spin asymmetry and cross-section ratio ($\sigma_{LT^{'}}/\sigma_{0}$) from the Kaon-LT Experiment. These are compared with the ground state reaction. The comparison of two reactions will be invaluable for our understanding of hadron GPDs.

Speaker: Ali Usman

(DPP) T1-7 Plasma Liquid Interaction | Interaction plasma/liquide (DPP)

138 Dynamics of nanosecond discharges in air in-contact with water

The application of a high E-field to a dielectric medium can induce ionization. The breakdown field of air at atmospheric pressure is around 30 kV/cm. If the electron avalanches produce more than ~10e8 charged species (Meek's criterium), an avalanche may transition to a streamer. The space charge field produced at the streamer head may exceed the breakdown field and supports its propagation in the medium. While the propagation of streamer in air is relatively well-understood, its interaction with solid or liquid surfaces complicates our understanding of the propagation mechanisms. More specifically, the properties of the material in front of the discharge, such as dielectric permittivity (ɛ_r) and electrical conductivity (σ), strongly influence the discharge dynamics. To investigate the influence of ɛ_r and σ on the discharge dynamics, we utilized liquids with varying permittivity (ranging from 32 to 80) and conductivity (ranging from 2 to 1000 μS/cm). The discharges were generated using single-shot nanosecond high voltage pulses and characterized both electrically and optically using ICCD images. Streamer propagation across a surface is primarily sustained by surface charging and charge accumulation. Accordingly, a decrease in ɛ_r accelerates surface charging, leading to more significant radial propagation, while an increase in σ results in the dissipation of surface charge accumulation in air from the ions present in the liquids, leading to reduced radial propagation. On the other hand, a 2D axisymmetric cylindrical fluid model is developed. The model consists of solving the fluid equations for the density of electrons, positive ions, and negative ions. The model is adapted to simulate the various conditions of ɛ_r and σ of the material in front of the discharge. The emission of the discharge acquired during its propagation is compared to the source term of electron impact avalanches. Such a simulation allows the determination of some fundamental properties that are hardly accessible experimentally such as the spatio-temporal evolution of the species density, the space charge density, and the E-field. The results are further processed to discuss the evolution of the pattern, particularly the disc-to-ring-to-dots transitions.

Speaker: Prof. Ahmad Hamdan

139 Atmospheric Pressure Streamer-Spark Discharge on Water Droplets: Production of silver Nanomaterials

Cold plasma-liquid interactions have emerged as a pivotal area of research, particularly for their applications in nanomaterial synthesis. This study explores atmospheric pressure streamer-spark discharges on water droplets, with a focus on the production of silver-based nanomaterials. By systematically varying experimental parameters such as droplet electrical conductivity (ranging from distilled water to 5 mS/cm.) and applied voltage (10-20 kV, 70-500 ns pulses), we investigated discharge dynamics in three distinct configurations: anodic-, cathodic-, and floating-droplet setups. The electrical behavior of the discharge-droplet system was characterized, while the temporal and spatial evolution of the discharges was captured using ICCD imaging.
In the case of droplets containing AgNO₃, the synthesized nanomaterials were analyzed using UV-Visible spectroscopy and transmission electron microscopy (TEM). The results revealed that specific discharge modes significantly influence the reduction of Ag⁺ ions by electrons, leading to the formation of diverse nanostructures. Notably, under certain conditions, Ag nanosheets were synthesized without the need for a substrate or a surfactant, highlighting the unique role of the droplet-air interface as a surrogate substrate. This finding opens new possibilities for substrate-free synthesis of oriented nanostructures, which are typically challenging to achieve without a template.
The interplay between discharge modes and droplet properties (e.g., electrical conductivity) governs the charge fluxes on the droplet, thereby dictating the morphology and structure of the synthesized nanomaterials. These insights not only advance our understanding of plasma-liquid interactions but also provide a versatile platform for the controlled synthesis of advanced nanomaterials. The ability to produce 2D nanostructures, such as Ag nanosheets, without a substrate underscores the potential of this approach for innovative applications in nanotechnology and materials science. This work paves the way for further exploration of plasma-driven synthesis techniques and their scalability for industrial applications.

Speaker: Lyes Sebih (Université de Montréal)

140 Cold Plasma Targeted Redox Therapy for Breast Cancer Bone Metastasis

Bone, especially the spine, is a common site for metastasis from breast, lung, and prostate cancers, often requiring aggressive treatments like chemotherapy and invasive surgery. These surgeries usually involve removing both the tumor and surrounding healthy tissue, creating voids that need reconstruction. Cold plasma therapy, operating at temperatures below 40°C, offers a non-invasive alternative by delivering reactive oxygen and nitrogen species (RONS) locally to the tumor site. However, understanding the precise interactions between plasma and tissues, along with determining the optimal treatment dosages, remains an active area of research. This project aims to develop a cold plasma source and investigate its potential to inhibit bone cancer metastasis, focusing on its anti-tumor effects. A platform was developed, combining a kHz coaxial dielectric barrier discharge plasma source with a bioprinted tumor-stroma interface model. The model, made of a cell-laden hydrogel (1% alginate and 7% gelatin), replicates a bone-like microenvironment by coculturing MDA-MB-231 breast cancer cells with human bone marrow mesenchymal stem cells (hbmMSCs). The effects of plasma treatment on cancer and healthy cells were measured through metabolic activity and live/dead assays over several days. Results demonstrated that the bioprinted hydrogel model was reproducible, and plasma treatment selectively targeted MDA-MB-231 cells while sparing hbmMSCs in both 2D and 3D cultures. Dose responses were evaluated, showing that plasma treatment parameters, including energy, gas composition, distance, and duration, could be fine-tuned to optimize the antitumor effects. Additionally, colorimetric assays confirmed that the production of long-lived reactive species (H2O2 and NO2-) could be controlled through these plasma parameters. This selectivity highlights the potential of plasma therapy as a targeted treatment for cancer, minimizing damage to healthy tissue. This research presents a promising platform for exploring cold plasma as a personalized, non-invasive treatment option for bone metastases, with the goal of integrating this technology into clinical practice.

Speaker: Laura Bouret (Polytechnique Montréal)

CAP_Abstract_Laura_2025.doc

(PPD) T1-8 New detectors and searches for dark matter II | Nouveaux détecteurs et recherche de la matière noire II (PPD)

141 IC443 3D Gammapy Analysis with VERITAS

IC443, a shell-type supernova remnant, provides a unique environment for studying cosmic ray acceleration at shock fronts and interactions with an adjacent molecular cloud. In this remnant, high-energy protons and nuclei interact with the dense interstellar medium, leading to gamma-ray production through pion decay.

My ongoing research utilizes VERITAS data and the advanced, open-source analysis framework Gammapy, which is specifically designed for imaging atmospheric Cherenkov telescope data. VERITAS (the Very Energetic Radiation Imaging Telescope Array System) is a ground-based observatory sensitive to gamma rays in the energy range of approximately 100 GeV to 30 TeV. Gammapy’s innovative 3D spatial and spectral modeling techniques extend traditional two-dimensional methods, enabling a more detailed examination of the gamma-ray emission.

The primary aim of this study is to constrain the spatial extension of IC443 and investigate potential regional variations in the gamma-ray production mechanisms. By employing techniques such as forward-folding and refined background modeling, the analysis seeks to distinguish between hadronic processes (pion decay) and possible leptonic contributions (inverse Compton scattering).

Speaker: Bryan Owens (Queen's University)

142 The MoEDAL-MAPP Facility - Expanding the LHC's Discovery Horizon

The Canadian led international MoEDAL-MAPP (MMF) facility at the LHC consists of four detectors: MoEDAL (approved in 2010), MAPP-1 (approved in 2021), the MAPP-1 Outrigger (submitted to the LHCC for approval), and, MAPP-2 (the NoI to be submitted in 2025). These detectors are designed to detect: Highly Ionizing Particle (HIP), Feebly Ionzing Particle (FIP), and Long Lived Particle (LLP) avatars of new physics with unprecedented sensitivity. We shall describe the physics production of the MoEDAL detector that has operated at LHC's Run-1, Run-2 and Run-3 and the physics program of MAPP-1+Outrigger and MAPP-2.

Speaker: James Pinfold (University of Alberta (CA))

143 The Forward Liquid Argon Experiment at the Forward Physics Facility for High Energy Neutrino and Dark Matter Searches at LHC

The proposed Forward Physics Facility (FPF) is an underground cavern at zero degrees to IP1 with the space and infrastructure to support a suite of far-forward experiments at the Large Hadron Collider in the High Luminosity era (HL-LHC). The Forward Liquid Argon Experiment (FLArE) is a Liquid Argon Time Projection Chamber (LArTPC) based detector designed for very high-energy neutrinos and search of dark matter in FPF, 620 m from the ATLAS interaction point in the far-forward direction. With a fiducial mass of 10 ton, FLArE will detect millions of neutrinos at the highest energies ever detected from a human source and will also search for Dark Matter particles with world-leading sensitivity in the MeV to GeV mass range. The LArTPC technology used in FLArE is well-studied for neutrino and dark matter experiments, however the use at the LHC requires specific targeted R&D. It offers excellent spatial resolution and particle identification. In this talk, I will overview the physics reach, the preliminary design, the needed detector R&D, and the prospects for international sponsors.

Speaker: Milind Vaman Diwan (Brookhaven National Laboratory (US))

144 ATLAS ITk upgrade for the HL-LHC

The Large Hadron Collider (LHC) is preparing to enter the high-luminosity era in a few years, where the ATLAS detector will operate under unprecedented conditions, with up to 200 proton-proton collisions per bunch crossing. This gives rise to technical challenges such as increased radiation damage, higher data rates, and detector occupancy, which require significant upgrades. To address these issues, ATLAS has designed and constructed a new all-silicon Inner Tracker (ITk) to replace the current Inner Detector. Many Canadian institutes play a leading role in the construction and commissioning of the ITk project. This talk provides an overview of the ITk layout, the current upgrade status, and the ATLAS collaboration’s efforts in preparing for this new detector integration in both hardware and software.

Speaker: HOANG DAI NGHIA NGUYEN (University of Montreal)

145 Characterizing the pre-production petals for the ATLAS Inner Tracker strip detector

For the High Luminosity Upgrade of the Large Hadron Collider, the ATLAS experiment will replace its current Inner Detector with an all-silicon Inner Tracker (ITk), which consists of pixel and strip systems. Relative to the current detector, the ITk features larger forward coverage, an order-of-magnitude increase in granularity, and improved radiation hardness. Its significantly enhanced tracking performance will enable precision measurements of fundamental physics. In the context of Higgs boson measurements, the ITk's larger forward coverage will increase the acceptance of Higgs boson production via vector-boson fusion by twofold, and the ITk's superior vertex reconstruction --- coupled with state-of-the-art particle identification algorithms --- will be crucial in probing the Higgs boson's self-coupling and its couplings to second-generation fermions.

The ITk strip system's forward detectors or "end-caps" will consist of 7,000 silicon sensor modules. These modules are mounted onto large, double-sided support structures called "petals" which provide readout, control, power, and cooling to the underlying modules. To facilitate the assembly of petals, an automated system has been developed consisting of a programmable gantry robot capable of dispensing adhesive as well as lifting and placing modules with micron-level precision. This automated system streamlines the production process and ensures uniformity across international production clusters.

This contribution presents the latest results from the assembly of the first pre-production ITk petals in Canada and globally, including the considerations of the automated system's design and the characterization of the mechanical and electrical performance of the petals post-assembly. This contribution will also summarize the design choices for the end-cap detectors which ensure robust operation at very cold ($\leq -35$ $^\circ\textrm{C}$) temperatures, as would occur during catastrophic cooling failures. Both topics are highly relevant to ongoing and future silicon detector design.

Speaker: Matthew Basso (TRIUMF (CA))

(PPD) T1-9 Neutrino experiments | Expériences de neutrinos (PPD)

146 Exploring the Nature of Neutrinos with the Deep Underground Neutrino Experiment (DUNE)

The Deep Underground Neutrino Experiment (DUNE) is a next-generation experimental program designed to study the behaviour of neutrino oscillation. DUNE will utilize a neutrino beam originating at Fermilab, near Chicago, and will leverage a detector at Fermilab (Near Detector) and a detector 1300 km away in South Dakota (Far Detector), south of Saskatchewan.

In the first phase of DUNE, its Far Detector will comprise of two 10,000 ton (fiducial) liquid argon (LAr) time-projection chamber (TPC) modules – powerful tracking calorimeter detectors – placed nearly a mile underground. With this large, sensitive, underground detector, DUNE aims to collect a high statistics and pure sample of neutrinos at the Far Detector. This setup also offers the potential to study non-beam physical processes via e.g. neutrinos produced in the atmosphere, supernova neutrino bursts, and/or solar neutrinos, etc. A second phase will aim to add more detector mass and expand the program.

The Near Detector will consist of a LAr TPC module as well: critical to constraining systematic uncertainties in the oscillation analysis. However, this LAr TPC will have a novel design using a pixel-based readout instead of the traditional wire-based readout. This and the segmentation of the LAr TPC into multiple units are crucial in mitigating the high multiplicity of neutrino interactions expected in any readout window given its proximity to the beam. The Near Detector will feature additional components and capability beyond the LAr TPC, allowing one to deeply characterize the neutrino flux.

Due to the complexity of this experimental program, several smaller-scale prototype detectors have been operating to test, validate, and improve both the technical designs and software for processing and analyzing events. By operating in charged particle test beams or neutrino beams, several of the prototypes are also capable of producing valuable results.

Canadian institutions are involved in the realization of the DUNE through efforts with both the Near and Far Detectors and prototypes. DUNE is anticipated to begin operating near the end of this decade/the beginning of the next. This talk will focus on the overall DUNE program, for example its ultimate plans, status, and the efforts with prototypes.

Speaker: Bruce Howard (York University & Fermilab)

147 Testing DUNE's Near Detector Strategy

The Deep Underground Neutrino Experiment (DUNE) is a next-generation long-baseline neutrino experiment designed to measure the leptonic CP phase and the neutrino mass ordering. To characterize the neutrino flux and constrain interaction models and systematic uncertainties, a suite of near detectors will be installed near the proton beam target. To address the high event pile-up over 50 interactions per 10 µs spill in the liquid argon TPC near detector (ND-LAr), a modular pixelated charge readout system has been developed, complemented by a high-coverage light detection system.
To evaluate the performance of this detector, four 0.7 ton modules were built and tested at the University of Bern with cosmic data, then assembled into a 2x2 array and placed on-axis in the NuMI neutrino beam at Fermilab. Repurposed tracker planes of the MINERvA detector were positioned both upstream and downstream to allow a better tracking of exiting particles and rejection of rock muon backgrounds. The detector collected about four days of high-quality data during the summer of 2024.
This talk will present the design of the 2x2 demonstrator, detailing both the charge and light readout systems, along with the first calibration and reconstruction efforts.

Speaker: Noe Roy (York University)

148 Water assays as a radon monitoring tool for the SNO+ experiment

The SNO+ experiment is a rare-event search experiment located at SNOLAB with its main goal being the search for neutrinoless double beta decay. This specialized search is highly sensitive, and therefore requires a very stringent radioactive background budget. Going deep underground provides 2km of overhead rock burden allows for very effective shielding from highly energetic cosmic rays that are constantly bombarding the surface of the Earth that would otherwise overwhelm the experiment.

While this shielding is effective, it provides new challenges due to the uranium and thorium that is naturally present in the surrounding rock. The uranium and thorium decay-chain produces radon gas that can emanate and create unwanted background noise within the detector. While there are currently mitigations in place to effectively reduce radon ingress into the ultra-pure water (UPW) shielding surrounding the detector, it is highly crucial to understand, quantify and monitor the radon content. SNO+ utilizes a well established assay system to do this.

Radon assays were developed for the original Sudbury Neutrino Observatory (SNO) experiment that now houses the SNO+ experiment. This assay technique is a unique testing and monitoring tool that separates radon gas from gas volume, and encloses it in a Lucas Cell. This Lucas Cell is specially designed to collect radon atoms. They then can interact in a scintillator surface when an alpha particle interacts with it, gets counted using PMTs, allowing for high accuracy when determining radon atom quantities.

These assays occur on a rotational basis and will continue to provide important information well into the future of the SNO+ experiment. The results from the more recent assays will be discussed as well as plans for trapping radon for the internal detector volume.

Speaker: Juliette DeLoye (SNOLAB)

149 Temperature Dependent Scintillation of Plastic Scintillators between 300 K and 4 K

Plastic scintillators are a common type of particle detector that is often used for their fast timing, robustness and cheap cost. Plastic scintillators are commonly used in veto systems since they can be made to large sizes needed for the experiment as well having a variety of dopants added to them to improve the detection of specific particles. As with any scintillator it is important to understand how the scintillator behaves in the environment that it will be in for the experiment. One consideration is the temperature that the scintillator will be operated at, specifically if the scintillator will be kept at cryogenic temperatures. Many inorganic scintillators have had their scintillation light yield determined at cryogenic temperatures, with many seeing an increase of up to 100\% more (eg.\url{http://link.aps.org/doi/10.1103/PhysRevB.84.214306}). To generalize such tests to plastic scintillators, I present the results of an experiment that analyzes the light yield of EJ-200, a commercial plastic scintillator from Eljen Technologies, between 300~K and 4~k using $\alpha$ excitation from an $^{241}$Am source. This study shows that the light yield decreases by 25\% as temperature changes between 300~K and 4~K. Preparations for a similar experiment using Compton scattering of $\gamma$ emissions from a $^{65}$Zn source and a $^{137}$Cs source are also presented.

Speaker: Nicholas Swidinsky (Queen's University)

150 The Ricochet Reactor CEνNS Experiment: First Light and Experiment Progress

RICOCHET is a coherent elastic neutrino-nucleus scattering (CE$\nu$NS) experiment situated 8.8 m from the core of the 58 MW research reactor at the Institut Laue-Langevin (ILL) in Grenoble, France. Using arrays of individually instrumented cryogenic bolometers, the experiment aims to measure the sub-keV$_{nr}$ cross section of CE$\nu$NS with low-energy recoils from reactor antineutrinos. RICOCHET would be among the first to observe this process from a reactor source and, beyond this, will provide a probe into low-energy neutrino processes. The primary RICOCHET payload (known as the CryoCube) consists of 18 42 g cryogenic germanium bolometers instrumented with ionization and NTD-based phonon readout. A second payload using superconducting TES-based detectors (Q-Array) is also in R&D, and will be implemented within the RICOCHET cryostat in future runs. In early 2024, RICOCHET completed its installation and commissioning phase at ILL, and has since completed three experimental runs: the first two as dual-bolometer runs, and a third run in early 2025 with 9 bolometers. The focus of these runs was on detector optimization, as well as the integration of inner shielding, electronics, and a muon veto system. The fourth experimental run is the first with the 18-detector CryoCube payload, reaching toward kg-scale detector volume. This talk outlines the performance results of the first experimental runs, the current status of the experiment, and a look toward reactor CE$\nu$NS detection.

Speaker: Elspeth Cudmore (University of Toronto)

CAP_Congress_Abstract__The_Ricochet_Reactor_CEvNS_Experiment__First_Light_and_Experiment_Progress.pdf

151 Response of the 20” Super-K PMT in Magnetic fields of up to 250mG

Super-Kamiokande (SK) is 50kT water Cherenkov neutrino detector composed of approximately 11,000 20” Photomultiplier Tubes (PMTs). Magnetic fields affect photoelectron trajectories through the bulb of large-sized PMTs and consequently can result in changes in the PMT gain and detection efficiency. For SK, it is becoming increasingly important to understand both the impact of residual magnetic field effects on PMT performance as well as the PMT angular response. The Photosensor Test Facility (PTF) at TRIUMF is a testbed designed to characterize the response of PMTs in various magnetic field configurations and light incident at different angles. Here we present new results investigating the gain, detection efficiency, and timing response of the 20” SK PMT in magnetic fields of up to 250mG. We also present simulation studies carried out in GEANT4 and COMSOL to investigate the optical effects on photon-absorption and the magnetic field effects on photoelectron trajectories in the PMT bulb and dynode in differing magnetic fields.

Speaker: Benjamin Randolph Smithers (TRIUMF (CA))

12:00 Break for Lunch (12h00-13h30) | Pause pour dîner (12h00-13h30)

Postdoctoral Fellows Networking Session (CAP) | Session de réseautage pour les boursiers postdoctoraux (ACP)

Science Policy Session - Forging CAP's Path: Science Policy and Advocacy in a Turbulent World | Session sur la politique scientifique

12:00 Forging CAP's Path: Science Policy & Advocacy in a Turbulent World

US scientific disruptions and declining public trust are eroding the research social contract and challenging open science globally, with inevitable impacts on Canada. This interactive CAP session aims to proactively shape our community's response. Following an introduction by CAP’s Director of Science Policy and Advocacy and identification of key themes, members will collaborate in groups on a topic of common interest. Together, we will develop concrete recommendations and strategic priorities for CAP's science policy and advocacy. Your insights are crucial for equipping CAP to champion a resilient, open scientific future for Canada. Come to contribute or just learn about science policy in Canada.

T-PLEN2 Teaching Medalist Plenary Session | Session plénière - Nancy Forde, SFU

152 Teaching Physics to a diverse student base

I am honoured to receive the CAP Medal for Excellence in Teaching Undergraduate Physics, which is a testament to the many colleagues and students who have inspired and helped me to become a better teacher. In this talk, I will highlight some of the approaches I’ve taken to making Physics accessible to students with diverse backgrounds and interests. For example, what I have done to engage a class of 200+ life science students in learning first-year electromagnetism? How do I teach third-year biophysics to students from multiple different departments and programs, with strongly varying backgrounds in Math and Physics? How do I motivate students to learn the course material? By sharing some of these ideas, I hope to stimulate discussion about how we can all improve as educators, in helping students to discover the beauty, wonder and utility of Physics.

Speaker: Nancy Forde

14:00 Travel Time | Durée du voyage

(DAPI) T2-1 | (DPAI) Applied Physics

153 Photon-to-Digital Converters – A 3D Integrated Digital SPAD Array Sensor for Photon Counting with High Timing Precision

We develop 3D integrated Photon-to-Digital Converters (PDC) for photon counting applications needing sub-nanosecond timing resolution. These applications range from LIDAR and quantum communication to radiation instrumentation and medical imaging.
In previous years we reported on the architecture of the PDCs, on their fabrication process, and on two electronic readouts: one optimized for low power large area integration using TSMC 180nm CMOS; the other TSMC 65nm CMOS embedding Time-to-Digital Converters (TDC) and processing electronics optimized for time-of-flight applications.
Fabrication of the first 3 wafers of PDC with low power readout was completed at the Teledyne DALSA foundry in Oct. 2024. The SPAD show expected performances with peak sensitivity >50% at 420 nm and dark count rate (DCR) of $0.1~\text{cps}/\mu\text{m}^2$. Within a PDC, the DCR of the 4096 SPADs was characterized, showing 5% to 7% of screamer SPADs with >10$\times$ the average DCR.

We will report on the PDC fabrication, wafer characterization, and SPAD performance of the low-power version. We will also report on the TDC performances and their integration in the TSMC 65nm CMOS readout being designed.

Speaker: Prof. Serge Charlebois (Université de Sherbrooke)

154 Development of a Portable Mobile X-ray System with Carbon Nanotube (CNT) Technology for Improved Diagnostic Imaging in ICU Settings

We are developing an integrated mobile X-ray system using carbon nanotube (CNT) technology to overcome the limitations of traditional 2D mobile chest radiography. By incorporating a CNT source array with electronics into a commercial cart, we aim to enable tomosynthesis (limited-angle tomography), providing quasi-3D imaging to improve visualization and diagnostic accuracy. This system is designed specifically for ICU patients who are too sick to be transported to radiology, who require daily chest radiographs to monitor pneumonia and assist with the placement of medical devices. The goal is to create a portable, scalable, and high-performance X-ray system that enhances accessibility to quality diagnostic imaging in critical care environments.

Speaker: Gavin Lyda

155 Consumer grade CMOS cameras as energy dispersive soft x-ray detectors

The advent and subsequent explosion of portable consumer electronics in the last twenty-five years has led to the development of mass produced, small form factor, high sensitivity, low noise and fast readout rate CMOS imaging sensors (CIS). These now ubiquitous CISs have found multiple scientific applications in nuclear physics and more recently have been adopted for x-ray fluorescence measurements in a single-photon counting regime for the soft x-ray range. Here we report a novel use of these CISs as low-cost detectors of fluorescence emission and soft x-ray scattering for x-ray absorption spectroscopy on the SGM Beamline, at the Canadian Light Source.

Speaker: Zachary Arthur (Canadian Light Source)

156 Radial TRASE: A 2D Slice-Selective RF Encoding MRI System

Transmit Array Spatial Encoding (TRASE) is an MRI encoding technique utilizing a transmit (Tx) array of radiofrequency (RF) phase gradient coils to achieve spatial encoding, rather than conventional switching gradients of the main magnetic field (B0). TRASE is particularly well suited to low-field, low-cost, and portable MRI systems utilizing lightweight permanent magnets, such as a Halbach array; however, interactions between the TRASE Tx array elements have caused significant challenges for 2D imaging. Here, we present a low-cost and slice-selective radial encoding scheme (Radial TRASE) for 2D TRASE imaging, which utilizes a simplified Tx array compared to prior 2D Cartesian TRASE sampling. The constructed system consists of two RF phase gradient coils capable of 1D encoding any transverse axis. By incremental mechanical rotation over a 90ᵒ range, the encoding axis can be changed, allowing a complete radial k-space acquisition. As a first demonstration, a wrist-sized coil pair was experimentally verified on a 2.0 MHz Halbach magnet, incorporating a static B0 slice-selection gradient. Although a high level of isolation is achievable geometrically (better than -20 dB), for a more robust implementation, we also demonstrate the capability of our active parallel transmit system (pTx) cancellation method. Through pTx compensation pulses, residual coupled currents remaining from geometric decoupling can be eliminated, with effective isolations of -50 dB being reached for the two-coil array. Radial TRASE encoded images of a line-pair phantom were acquired, achieving a resolution better than 3.33 mm/lp with minimal coupling related encoding artifacts, indicating the advantage of the simplified Tx array. Mechanical rotation of the Tx array was performed during the TR period, which caused no imaging delays. By both eliminating the requirement for a switched B0 gradient subsystem and further simplifying the RF implementation, this MRI configuration is particularly promising for applications resonating at the lowest end of the NMR spectrum of technical complexity.

Speakers: Christopher Sedlock (University of Alberta), Prof. Jonathan Sharp (University of Alberta)

CJS_CAP_Radial_TRASE.docx

157 Leveraging Water-Cherenkov Experiment Experience for Drinking Water Monitoring

The Water Monitoring System (WMS) developed at TRIUMF is a novel approach to in-situ water-quality monitoring. Initially, it was developed to track the quality of water samples from water Cherenkov neutrino detectors; the system uses several LEDs along with toggleable filters, a UV sterilizer, and a water deionizer to identify the presence and type of contaminants in a water sample. It has recently been deployed and operated to monitor the water quality of the Water Cherenkov Test Experiment (WCTE) at CERN; there, the system was used to track the initial purification of the detector’s tank water, to monitor the quality of the water during its normal operation, and to track water quality decline during times when water circulation was paused. The WMS has also shown promise as a deployable water-quality monitor that can be used beyond physics applications in communities with unreliable access to clean water where fast and accurate water monitoring is imperative. Results and interpretations of the first deployment of the system for the WCTE are shown along with future applications and expected efficiencies.

Speaker: Benjamin Randolph Smithers (TRIUMF (CA))

(DTP) T2-10 Classical gravity and general relativity | Gravité classique et relativité générale (DPT)

158 Black Holes and Wave Equations

Two decades ago, we understood that small, four-dimensional, rotating black holes are unstable by solving wave equations, and the superradiance instability and black hole bomb mechanism became popular. Since then, what did we learn from wave equations? In this talk, I will briefly explain the wave equation analysis and current applications for black holes.

Speaker: Turkuler Durgut (Mount Allison University)

159 Black Hole Dissolution via External Fields

We know of two ways in which a black hole can end. The first is by black hole evaporation via the emission of Hawking radiation. This is an extremely slow process by which a solar mass black hole expected to take on the order of $10^{67}$ years to evaporate. We dub the second method black hole dissolution and, in contrast, this is a fast process whose early stages are the gravitational wave signatures of black hole mergers that have been observed hundreds of times by LIGO-VIRGO-KAGRA. During a black merger, two black holes become one. While the final stages are hidden by the common event horizon, inside that final black hole the two original black holes encounter intense gravitational fields comparable to those binding themselves and they ultimately dissolve in this region of strong spacetime curvature and lose their individual identities.

In this talk, I will present recent some recent results in which a similar dissolution can be studied in exact Weyl solutions which describe black holes that are distorted by strong external fields. This distortion may be tuned beyond the point at which their apparent horizons (feel free to read apparent in either a technical or general sense!) are no longer boundaries between trapped and untrapped regions.

Speaker: Dr Ivan Booth (Memorial University)

160 Spacetime Penrose Inequality for Cohomogeneity One Initial Data

The spacetime Penrose inequality (SPI) is a geometric inequality bounding the mass of an asymptotically flat black hole from below in terms of the area of its event horizon. It has been proved in the setting of time symmetric initial data (the Riemannian Penrose inequality). We outline a proof of the SPI for asymptotically flat 2(n+1)-dimensional initial data sets which are invariant under a cohomogeneity one action of SU(n+1). Analogous results are obtained for asymptotically hyperbolic initial data that arise as spatial hypersurfaces in asymptotically Anti de-Sitter spacetimes. The inequality is saturated if and only if the initial data isometrically embed into a Schwarzschild(-AdS) spacetime. The proof relies on the generalized Jang equation approach of High Bray and Marcus Khuri.

Speaker: Prof. Hari Kunduri (McMaster University, Mathematics and Physics)

161 General Formalism of the Quantum Equivalence Principle

A consistent theory of quantum gravity will require a fully quantum formulation of the classical equivalence principle. Such a formulation has been recently proposed in terms of the equality of the rest, inertial and gravitational mass operators, and for non-relativistic particles in a weak gravitational field. In this work, we propose a generalization to a fully relativistic formalism of the quantum equivalence principle, valid for all background space-times, as well as for massive bosons and fermions. The principle is trivially satisfied for massless particles. We show that if the equivalence principle is broken at the quantum level, it implies the modification of the standard Lorentz transformations in flat space-time and a corresponding modification of the metric in curved space-time by the different mass ratios. In other words, the observed geometry would effectively depend on the properties of the test particle. Testable predictions of potential violations of the quantum equivalence principle are proposed.

Speaker: Mitja Fridman

162 A New Look at Quark Stars

Quark stars — a gravitationally bound quark-gluon plasma — have been
hypothesized to be the last gravitationally stable state of matter preceding collapse into a black hole. Originally such stars were thought to necessarily contain a significant component of strange quarks, but recent work has shown that up-down quark matter can be more stable than ordinary nuclei at sufficiently large baryon number beyond the periodic table. I shall describe how such up-down quark stars open up new possibilities for astrophysical searches for such objects as well as new tests of general relativity.

Speaker: Robert Mann

(DPMB) T2-11 | (DPMB)

163 Biophysics of neurodegeneration: molecular mechanisms of Alzheimer's disease, towards prevention and cure

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by dementia and memory loss for which no cure or prevention is available. Amyloid toxicity is a result of the non-specific interaction of toxic amyloid oligomers with the plasma membrane. We use biophysical approaches such as atomic force microscopy (AFM), Kelvin probe force
microscopy (KPFM), black lipid membrane (BLM) and surface plasmon resonance (SPR) and other methods to study amyloid aggregation and interaction of amyloid beta (1-42) peptide with lipid membranes.

We tested a set of novel pseudo-peptide inhibitors (potential drug candidates) and showed that they effectively prevent amyloid-amyloid binding on a single molecule level and work well in cellular models to prevent amyloid toxicity. We demonstrated that changes in lipid composition lead to changes in nanoscale membrane structure and alter the membrane-amyloid interactions. We showed that healthy models (HM) are less susceptible to amyloid damage than models mimicking AD-neurons. This possibility of amyloid to recognize the changes in membrane structure and properties opens possibilities to protect the membrane against amyloid toxicity. We studied effects of small molecules that can change the properties of lipid membranes as a way to prevent amyloid induced damage. We found that neuroactive hormone melatonin can efficiently protect the membrane models mimicking early stages of AD but not the late stage of AD. Neuroprotective effects of trehalose and the role of Li salts in neurodegeneration will be also discussed. These findings contribute to a better understanding of the molecular mechanisms of AD and aid to the development of novel strategies for its cure and prevention.

Speaker: Zoya Leonenko (Depts. of Physics & Astronomy and Biology, Waterloo Institute for Nanotechnology, U. Waterloo)

164 The Aurora-RT – the Canadian Home-Grown Linac-MR Treatment Platform at the Cross Cancer Institute

Invented and developed at the Cross Cancer Institute in Edmonton, Alberta, the MagnetTx Aurora-RT is a made in Canada solution that combines a 6 MV linac producing therapeutic radiation and a biplanar 0.5 T MRI. This treatment platform received FDA clearance and treated its first patients recently. The primary benefit of such a device is to provide 3D MRI with excellent soft tissue contrast at start of treatment to manage inter-fractional organ motion, and real time 2D MRI to monitor intra-fractional organ motion during radiation delivery. Compared to other MR-Linac systems, the Aurora RT has a wide bore (60 cm x 110 cm) and a geometry that ensures the main magnetic field of the system is always parallel with the radiation field, which is unique to other commercials MR-Linac systems which are perpendicular. Secondary electrons generated by X-ray beams are highly forwarded peaked, thus a perpendicular magnetic field perturbs the dose more strongly via Lorentz force which leads to shifting of depth dose curves, crossplane beam profiles and Electron Return Effects, which is largely avoided in our parallel field. Our initial commissioning work confirms the minimal influence of the parallel magnetic field in beam modeling in water phantom, reference dose calibration, and IMRT dose accuracy, thus allowing initial patient treatments with off-the-shelve treatment planning systems that do not explicitly model magnetic field effects. However, clinicians should be aware that parallel magnetic field can still act on lateral electrons to cause dose perturbations in certain situations, such as at the patient’s surface, in lung, and orthogonal interfaces. These situations are investigated with Monte Carlo simulations. Finally, a collaboration is underway with a commercial partner for a treatment planning system that accounts for these parallel magnetic field effects of our Linac-MR system and initial results are promising.

Speaker: Eugene Yip (Dept. of Oncology, University of Alberta)

(DASP) T2-2 Space Weather, Space Instrumentation, and Operations | Météo spatiale, instrumentation spatiale et opérations (DPAE)

Convener: Daniel Billett (University of Saskatchewan)

165 The effect of auroral absorption events on HF propagation links over Canada

Natural Resources Canada (NRCan) operates several over-the-horizon (OTH) High Frequency (HF) radio links across Canada. From 2013-2019, a dedicated link between a transmitter in Ottawa to a receiver in Alert was operated nearly continuously at 6 different HF frequencies from 5 to 14 MHz. For an OTH propagation link to exist between Ottawa and Alert at a given frequency, two criteria must be met: the overall ionospheric electron density between Ottawa and Alert must be sufficient to allow 1, 2, or 3 hop propagation between Ottawa and Alert and the D-region density must be low enough to have minimal absorption along this long propagation path. In this period, the University of Calgary was also operating several 30-MHz GO-Canada riometers across Canada. In this study, we examine the relation between absorption measurements made by the riometers and the likelihood of dropouts in the NRCan HF link. For times when the F-region ionospheric density tends to be sufficient to support propagation links, losses of signal at Alert tend to correspond to higher measurements of absorption at most riometer sites across Canada. Since the riometer measurements from the GO-Canada network are not exactly co-located with the predicted HF link path and D-region pierce points, considerations of the scale sizes of auroral absorption regions need to be made. Also, the dependence of transmission frequency on the absorption measured during dropouts is considered. Overall, the results of this study will provide a deeper understanding of the connection between absorption at 30 MHz and the corresponding effects on lower frequency HF links in the same region.

Speaker: Rob Gillies (University of Calgary)

166 Canadian High Arctic Scintillation Model (CHASM): Status Update

The high-latitude ionosphere is a dynamic and hostile environment for communication and navigation systems due to its high occurrence rate of instabilities of variable temporal and spatial scales. Small-scale ionospheric irregularities can cause rapid and random fluctuations in the phase and amplitude of Global Navigation Satellite System (GNSS) signals, leading to a phenomenon referred to as scintillation. Scintillation can result in cycle slips or losses of signal lock, which can significantly impair the performance of GNSS-based applications.

Previous studies have shown that at high latitudes, the probability of amplitude scintillation occurrence in GNSS signals is smaller than that of signal phase fluctuations, with typical seasonal, local time, and geomagnetic activity dependences. Despite efforts from different research reports, existing scintillation models are ineffective at high latitudes.

The principal objective of the present work is to develop a high spatial and temporal resolution model to predict the probability of occurrence of amplitude scintillation and phase fluctuations in GNSS signals in the Canadian Arctic. Using data collected by GNSS scintillation monitors of Canadian High Arctic Ionospheric Network (CHAIN) over a fifteen-year time frame, the model will use Bayesian statistical inferences to analyze scintillation patterns based on various levels of solar activity, solar wind conditions, and geomagnetic indices.

In this presentation, the outcomes of an extensive data curation process, encompassing fifteen years of raw GPS data from 25 stations across the Canadian High Arctic, will be discussed. The climatological behavior of scintillation occurrences is analyzed, with emphasis on seasonal, diurnal, and geomagnetic activity patterns. These analyses not only delineate the underlying scintillation climatology but also inform the development of a high-resolution predictive model of the physical drivers, ultimately advancing our capability to mitigate the impacts of ionospheric disturbances on GNSS-based systems.

Speaker: Melika Bazargani (Graduate student (MSc in physics) at physics department of University of New Brunswick, Fredericton, NB, Canada)

DASP2025_Melika_AK_Karim_Jay.pdf

167 The RADICALS High Energy Particle Telescope (RADHEPT) Instrument Suite

The RADiation Impacts on Climate and Atmospheric Loss Satellite (RADICALS) mission will explore the precipitation of high energy electrons and protons from the Van Allen belts into the thermosphere and mesosphere. These high energy electrons and protons are believed to have important impacts on the generation of NOx and HOx free radicals in these regions leading to the catalytic destruction of ozone in the upper stratosphere, ultimately leading to impacts on the Earth’s climate all the way to the troposphere due to changes in whole atmosphere energy transfer. Such precipitating energetic particles can also affect the transmission and reflection of radio waves in the ionosphere, with impacts for aircraft operations over the poles. An increased understanding of the mechanisms leading to energetic particle precipitation, particularly during solar storms, and the distribution of particle flux as a function of pitch angle is important in order to fully predict the energy input and therefore the effect of such radiation on these processes. The High Energy Particle Suite of instruments for RADICALS is designed to measure the trapped and precipitating particle distribution functions as a function of pitch angle using a pair of directional telescope detectors based on dE/dx silicon stacks mounted on the spinning RADICALS plaform. This will consist of the high energy RADHEPT-HE instrument, which will measure the electron and proton fluxes in the energy ranges of 0.8 to 4.0 MeV and 7 to 40 MeV respectively, and the low energy RADHEPT-LE instruments, which will measure the electron and proton fluxes in the energy ranges of 0.2 to 1.0 MeV and 2 to 10 MeV respectively. In addition, a faster, omni-directional detector, based on scintillator/SiPM sensors, will be used to measure Micro Burst radiation with a 10 ms time resolution. Two separate sets of instruments will have two look directions, 180 degrees apart, allowing for a complete 360 degree angular scan of particle distribution functions every 15 seconds for a satellite spin rate of once every 30 seconds. The current design and specifications for the instruments will be presented.

Speaker: Robert Fedosejevs (University of Alberta)

168 Robust electron density inferences with multivariate regression

The measurement of electron densities in the ionosphere is notorious difficult. In situ measurements are typically made using Langmuir probe characteristics from which densities and temperatures are inferred using a variety of analytic models. These include but not limited to the Orbital Motion Limited (OML) introduced a century ago by Tonks and Langmuir (Physical review 34.6 (1929): 876), and empirical corrections constructed using comparisons with other measurements. Analytic models however are based on simplifying assumptions, which don’t account for the full complexity of the conditions under which measurements are made. Electron densities can also be measured remotely using techniques such ionosondes, Incoherent Scattering Radars (ISR), and Total Electron Contents obtained from arrays of GPS satellites and ground stations. These remote sensing measurements have their limitations due to the distance between instruments and plasma being diagnosed. As a result, these measurements typically sample large volumes of ionospheric plasma, over times in which plasma physical parameters can vary significantly. As such, remote sensing cannot be expected to provide the spatial and temporal resolution in measurements that are directly comparable to in situ measurements made with particle sensors mounted on satellites. In this presentation, multivariate regression is applied to construct a simple and efficient model to infer ionospheric densities by combining kinetic simulations capable of accounting for actual conditions under which in situ measurements are made, with machine learning techniques. The robustness the model to noise is also assessed and quantified by augmenting data sets obtained from simulations, in which different levels of noise is introduced. The results show that densities can be measured with a relative uncertainty of order 30% or less under realistic conditions.

Speaker: Richard Marchand (University of Alberta)

169 Enhanced operation of SuperDARN radars with the Borealis radar system

The Borealis radar system developed by SuperDARN Canada at the University of Saskatchewan has enabled new operating modes for SuperDARN radars. Two new operating regimes have been used by SuperDARN Canada: simultaneous sensing of the full field-of-view (FOV), and multistatic sensing. Full FOV illumination increases the temporal resolution sixteen-fold, while multistatic sensing probes novel plasma velocity vectors. Initial observations using a wide transmission beam exhibited some artifacts detrimental to geolocation. In this talk, besides the details of new operation regimes, enhancements to the full FOV mode that mitigate said artifacts will be discussed.

Speaker: Remington Rohel (University of Saskatchewan)

170 Investigating Space Radiation and Atmospheric Climate Impacts with the Canadian RADICALS Mission

The RADiation Impacts on Climate and Atmospheric Loss Satellite (RADICALS) mission, scheduled for launch in 2027, is a Canadian small satellite mission designed to investigate the impacts of energetic particle precipitation on Earth’s atmosphere. Energetic particle precipitation (EPP) plays a critical role in altering atmospheric chemistry, particularly through the production of NOx and HOx, which catalytically destroy ozone in the middle atmosphere. RADICALS will focus on measuring the energy input from precipitating energetic particles into the atmosphere, shedding new light on the connection between space weather and climate. Operating in a polar orbit, the RADICALS payload contains dual High Energy Particle Telescope (HEPT) suites (each comprising high and low energy telescopes, and a high temporal resolution scintillator), and dual X-Ray Imager (XRI) suites. When mounted on the spinning RADICALS spacecraft they will provide pitch angle distributions of trapped radiation belt electrons and solar energetic protons, and the associated Bremsstrahlung X-rays from atmospheric interactions. The mission's unique back-to-back HEPT suite design will measure both down-going and up-going particles simultaneously, while the XRI will remotely sense particle precipitation via X-ray emissions as well as monitoring lower energy electrons as a secondary product. This combination will allow RADICALS to pitch angle resolve the precipitating electron and protons across a wide range of energies on various timescales, including that of electron microbursts which are believed to play a potentially significant role in atmospheric energy input. The RADICALS science payload will also include a pair of boom-mounted fluxgate magnetometers and a 3-axis search coil magnetometer to substantiate particle measurements with the local magnetic wave activity. By resolving the electron loss cone and quantifying the energy flux of precipitating particles, RADICALS will provide essential data for understanding how space radiation influences atmospheric chemistry, particularly during geomagnetic storms. These measurements will be critical inputs for both radiation belt models as well as for coupled whole atmosphere models, and overall for assessing the role of energetic particle precipitation on climate.

Speaker: Ian Mann (University of Alberta)

(DAMOPC) T2-3 Stored Ions and Quantum Control | Ions stockés et contrôle quantique (DPAMPC)

171 A Quantum Structural Phase Transition in Trapped Ion Crystals

Arrays of trapped ions offer precise control over both internal quantum states and collective vibrational motion. Here, we demonstrate the manipulation of vibrational modes in ion arrays to drive the 1D linear–2D zigzag quantum structural phase transition. This system provides an intrinsic source of novel entangled states of ion crystal structures, which can be manipulated through trapped ion double-well interferometry. I will discuss how we experimentally control and characterize this transition in a linear Paul trap, using Raman sideband spectroscopy to probe energy levels and motional distributions near the critical point. Finally, I will explore coherence assessment and potential applications in in-situ electric field noise sensing.

Speaker: Paul C Haljan (Department of Physics, Simon Fraser University)

172 Qutrits and geometric phase via quantum control in ultracold spin-1 systems

Using the exceptional controllability of an ultracold atoms platform, we explore novel approaches to quantum state preparation and transformation using radio- and microwave-frequency fields. As an introductory example of such state control, we explored a three-level subset of rubidium-87's ground states and created atomic "qutrits," demonstrating the capacity to create arbitrary states, and to perform single-qutrit operations on them [1]. In another set of experiments, we make use of geometric rather than dynamical phase [2]. By dressing the atoms with frequency-modulated electromagnetic fields, we prepare an effectively degenerate manifold of basis states that allows us to apply non-Abelian geometric phases. We vary the parameters of the dressing field to traverse complete loops, known as holonomies, in an abstract parameter space, and can transform the quantum states, performing the equivalent of single-qubit operations. We evaluate the experimental performance of this protocol in an ensemble of ultracold rubidium-87 atoms and develop insight into the true robustness of the scheme under practical conditions. From here, we see new opportunities for exploring beyond the single-particle regime to explore geometric phases in many-body systems.

[1] Joseph Lindon, Arina Tashchilina, Logan W. Cooke, Lindsay J. LeBlanc
Phys. Rev. Appl. 19, 034089 (2023)
[2] Logan W. Cooke, Arina Tashchilina, Mason Protter, Joseph Lindon, Tian Ooi, Frank Marsiglio, Joseph Maciejko, Lindsay J. LeBlanc. Phys. Rev. Research 6, 013057 (2024).

Speaker: Lindsay LeBlanc (University of Alberta)

173 Quantum quenches in the two-component Bose-Hubbard model

Cold atoms in optical lattices can be used as quantum simulators to study the temporal evolution of quantum systems, which has lead to increasing interest in the out-of-equilibrium dynamics of bosons in optical lattices. Adding a second species of bosons introduces a wide range of novel quantum phases and provides a platform to explore analogues of spin systems. We study the Bose-Hubbard model for two-component bosons using a strong-coupling approach within the closed-time-path formalism and develop an effective theory for the action of this problem. We obtain equations of motion for the superfluid order parameter and study these in the low frequency, long wavelength limit during a quantum quench for various initial conditions.

Speaker: Florian Baer (Simon Fraser University)

15:30 Discussion / Networking

(DCMMP) T2-4 Special Session - Physics, Climate change, and the transition to sustainability / Physique, changement climatique et transition vers la durabilité (DPMCM)

174 A strategic approach for Canada to achieving carbon neutrality

Like most wealthy countries, Canada has committed to achieving carbon neutrality by 2050. Reaching this target requires a fundamental reassessment of our energy system and the abandonment of partial greenhouse gas (GHG) reduction strategies, through energy efficiency, that have dominated the transition in recent years. As we move forward, analyses suggest that achieving this transformation by 2050 will require strategic approaches that integrate both sectoral and systemic perspectives, going far beyond a mere collection of individual actions.

Drawing on, among other sources, the findings of the 3rd edition of Canadian Energy Outlook from the Institut de l'énergie Trottier(*) and of the Transition Accelerator, I will discuss the challenges and potential approaches to achieving carbon neutrality, focusing on recent trends, technological evolutions and analyses of the infrastructures needed to reach net-zero by 2050. I will conclude on what Canada can benefit and lose in going forward irrespective of the current political situation.

• S. Langlois-Bertrand, N. Mousseau and L. Beaumier (Eds.), Canadian Energy Outlook 3rd edition, Institut de l’énergie Trottier – Polytechnique Montréal. http://iet.polymtl. ca/energy-outlook/

Speaker: Prof. Normand Mousseau (Université de Montréal)

175 Roles for materials physicists in carbon dioxide removal strategies

Even though large-scale carbon dioxide removal (CDR) technologies are not yet well-developed and bring a range of risks, they are also recognized as an integral part of any strategy to successfully limit global warming. In this context, I will provide a brief overview of several high-profile climate policy documents [1-3] that describe the current state of CDR technologies, and highlight specific identified challenges where materials physics could help advance CDR solutions. Following this, I will show examples from my own research program that aim to train physics students within multi-disciplinary collaborations that focus on linking fundamental science with the development of regionally appropriate CDR strategies.

[1] IPCC, Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, edited by H. Lee and J. Romero (IPCC, Geneva, Switzerland, 184 pp., 2023). DOI:10.59327/IPCC/AR6-9789291691647

[2] Washington Taylor, Brad Marston, Robert Rosner, and Jonathan Wurtele, PRX Energy 4, 017001 (2025). DOI: PRXEnergy.4.017001

[3] US Department of Energy Office of Science, Basic Energy Sciences Roundtable, Foundational Science for Carbon Dioxide Removal Technologies (Washington, D.C., USA, 4 pp., 2022). DOI: 10.2172/1868525

Speaker: Kristin Poduska

176 SLO/GO Degradation-Loss Sensitivity in Climate-Human System Coupling

The potential of extreme environmental change driven by a destabilized climate system is an alarming prospect for humanity. But the intricate, subtle ways Earth's climate couples to social and economic systems raise the question of when more incremental climate change signals the need for alarm. Questions about incremental sensitivity are particularly crucial for human systems that are organized by optimization. Optimization is most valuable in resolving complex interactions among multiple factors, however, those interactions can obscure coupling to underlying drivers such as environmental degradation. Here, using Multi-Objective Land Allocation as an example, we show that model features that are common across non-convex optimization problems drive hypersensitivities in climate-induced degradation--loss response. We show that catastrophic losses in human systems can occur well before catastrophic climate collapse. We find punctuated insensitive/hypersensitive degradation--loss response, which we trace to the contrasting effects of environmental degradation on subleading, local versus global optima (SLO/GO). We argue that the SLO/GO response we identify in land-allocation problems traces to features that are common across non-convex optimization problems more broadly. Given the broad range of human systems that rely on non-convex optimization, our results therefore suggest that substantial social and economic risks could be lurking in a broad range in human systems that are coupled to the environment, even in the absence of catastrophic changes to the environment itself.

Speaker: Greg van Anders

177 Effects of Hillslope Geomorphology on Water Track Pattern Formation

Hillslopes in the Canadian High Arctic can express curious features called water tracks, where stone and soil domains self-organize into quasi-linear patterns. Though they physically resemble rills, they are not characterized by sustained surface flows following rainfall or snowmelt; hence, no obvious evidence of active particle transport downslope is observed. This motivates several questions which at present are little explored. First, how does hillslope geomorphology affect the cross- and down-slope topographic patterns that we see? Second, by what mechanism(s) (e.g., freeze-thaw, granular, fluid-flow-driven) do water track patterns develop? Answers to these questions have broad implications for periglacial geomorphology because water tracks are thought to play an important role in the development of channel networks and are particularly important in water-limited polar desert environments. Deepening of the active layer in response to climate change will increase the potential for further incision and expansion of water tracks.
Our goal is to begin to address these knowledge gaps through a multi-disciplinary approach combining field and modelling techniques. We created a digital elevation model (DEM) of a field site on Devon Island, Nunavut using topographic LiDAR data to assess the connections between hillslope geomorphology and water track shape. Spectral analysis shows a finite range of wavelengths between 1-2 meters, rather than one dominant feature wavelength, characterizing the highest spectral powers. We find no correlation between hillslope gradient and feature wavelength distribution. Last, using the hillslope DEM, we map the water track network to determine the dominant length scales and their correlation to topographic metrics of the hillslope.
The diversity of water track wavelength and length scales, along with the varying relationships identified between the features and the hillslope, suggests the study site is in an early stage of response to the ongoing amplified Arctic climate change. Therefore, we anticipate continued development into the foreseeable future, with implications for expansion of the existing local drainage network as the warming climate deepens the active layer through which hydrologic processes occur.

Speaker: Grace Johnson (Department of Physics, Simon Fraser University)

(DGEP) T2-5 Physics for Everyone | La physique pour tous (DEGP)

14:15 Invited speaker abstract to come - A.W.

178 Strategies for Improving Gender Diversity in Physics

With less than a quarter of physics degrees being earned by women, gender equity in physics can seem far away. Yet there has been significant change over the last few decades, and today's young women experience a much more welcoming field than did their predecessors. This talk will present some of the underlying reasons for the lower proportion of women in our field, along with strategies that individuals and groups can use to promote gender equity. From organizational change to daily habits, we all can help physics improve by becoming more welcoming.

Speaker: Laura McCullough (University of Wisconsin-Stout (USA))

179 A novel approach to reaching gender parity in physics

Despite ongoing efforts, women remain underrepresented in STEM, particularly in leadership roles. Parité Sciences is a bold initiative advancing gender parity in STEM by training teachers throughout Canada—key influencers in shaping students' scientific identity. Rather than focusing solely on students or institutions, we equip educators with the tools to foster inclusive learning environments, counteract biases, and inspire diverse talent in science.

Since a single teacher can impact hundreds of students over their career, this approach creates a powerful multiplier effect, embedding gender equity into the foundation of science education. In this talk, I will present the mission and impact of Parité Sciences, highlighting how our evidence-based programs are driving long-term change in STEM representation.

Speaker: Julie Hlavacek-Larrondo (Université de Montréal)

15:30 Discussion / Networking

(DNP) T2-6 Nuclear Theory | Théorie nucléaire (DPN)

180 First principles theory for nuclear structure, astrophysics, and new-physics searches

Answers to some of the most fundamental questions in science, such as the mass and character of the neutrino, the nature of dark matter, or the abundance of matter over antimatter, might very well reside in the physics of the atomic nucleus. As the role of nuclei in unraveling such mysteries continues to deepen, first-principles quantum simulations, beginning from only underlying nuclear/weak forces, are currently undergoing nothing short of a revolution. Long considered a collection of disconnected phenomenological models, breakthroughs in our treatment of nuclear forces rooted in QCD, the strongly interacting many-body problem, and AI/machine learning techniques are transforming modern nuclear theory into a true first-principles discipline.

In this talk I will outline this next-generation "ab initio" philosophy and spotlight several recent milestones for nuclear structure/astrophysics, including statistical predictions of the limits of nuclei, the neutron skin of 208Pb to constrain neutron star properties, and new results informing r-process nucleosynthesis simulations in the N=126 region. I will then focus on our parallel advances driving first ab initio predictions of neutrinoless double-beta decay, WIMP- and neutrino-nucleus scattering, and symmetry-violating moments, with quantifiable uncertainties, for essentially all nuclei relevant in searches for new physics.

Speaker: Jason Holt

181 Ab initio calculations of nuclear parity-violating moments and nuclear structure corrections for tests of fundamental symmetries

First principles, or ab initio, nuclear theory describes atomic nuclei as systems of nucleons interacting by QCD-based chiral effective field theory (EFT) nucleon-nucleon and three-nucleon forces. In combination with chiral EFT electroweak currents, ab initio nuclear calculations can provide model-independent results with quantifiable uncertainties relevant for precision electroweak physics.
We will discuss large-scale calculations performed within the ab initio no-core shell model (NCSM) [1] for observables requiring a computation of the nuclear Green’s function that we construct by applying the continued fraction Lanczos algorithm [2]. We will review recent results for parity violating anapole [3], electric dipole [4], and Schiff moments in light atomic nuclei. Also, we will present ongoing calculations of two-photon exchange nuclear structure dependent corrections needed to extract nuclear radii from the measured X-ray spectra of muonic atoms and highlight the effort to compute nuclear structure corrections for the extraction of the Vud matrix element from the superallowed Fermi transition measurements [5].

Supported by the NSERC Grant No. SAPIN-2022-00019. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada. Computing support came from an INCITE Award on the Summit and Frontier supercomputers of the Oak Ridge Leadership Computing Facility (OLCF) at ORNL, from the Digital Research Alliance of Canada, and from the LLNL institutional Computing Grand Challenge Program.

[1] B. R. Barrett, P. Navratil, J. P. Vary, Progress in Particle and Nuclear Physics 69, 131 (2013). [2] M. A. Marchisio, N. Barnea, W. Leidemann, G. Orlandini, Few-Body Syst. 33, 259 (2003). [3] Yongliang Hao, Petr Navratil, Eric B. Norrgard, Miroslav Ilias, Ephraim Eliav, Rob G. E. Timmermans, Victor V. Flambaum, and Anastasia Borschevsky, “Nuclear spin-dependent parity-violating effects in light polyatomic molecules,” Phys. Rev. A 102, 052828 (2020). [4] Paul Froese and Petr Navratil, “Ab initio calculations of electric dipole moments of light nuclei,” Phys. Rev. C 104, 025502 (2021). [5] Michael Gennari, Mehdi Drissi, Mikhail Gorchtein, Petr Navratil, and Chien-Yeah Seng, “Ab initio calculation of the nuclear-structure-dependent radiative corrections in 10C superallowed transition,” Phys. Rev. Lett. 134, 012501 (2025).

Speaker: Petr Navratil

182 Modelling electroweak processes in light nuclei: Nuclear Fermi decays and $ V_{ud} $

Currently, the most precise extraction of the up-down quark mixing element $ V_{ud} $ of the Cabibbo-Kobayashi-Maskawa (CKM) matrix comes from a handful of $ft$-value measurements for nuclear Fermi decays in light- and medium-mass nuclei. However, a complete extraction of $ V_{ud} $ from hadronic decays requires challenging theory determinations of hadronic-structure-dependent electroweak radiative corrections (EWRC) to said decays. In fact, a novel evaluation of the free-hadron part of the dominant correction to nuclear Fermi decays, i.e., the free-hadron $\gamma W$-box diagram, has led to tension with the Standard Model expectation of CKM unitarity. Moreover, to reach the current precision goals for the CKM unitarity test via extraction of $ V_{ud} $ from nuclear Fermi decays, a consistent treatment of the hadronic-structure-dependent EWRCs in the nuclear medium is critical. Confirmation of this tension by way of increasingly precise nuclear theory and experiment would point towards a deficiency in the Standard Model (SM) weak sector.

Ultimately, this amounts to requiring a modern evaluation of the nuclear $\gamma W$-box diagram utilizing the ever-advancing set of tools available in nuclear many-body theory. Targeting an evaluation of the $\gamma W$-box diagram for the $^{10}\text{C} \rightarrow {}^{10}\text{B}$ and $^{14}\text{O} \rightarrow {}^{14}\text{N}$ Fermi transitions, we apply the no-core shell model (NCSM). The NCSM is a non-relativistic quantum many-body approach for modelling the low-lying bound states of light nuclei starting solely from inter-nucleonic interactions. Augmented by the Lanczos strengths method, the NCSM can be further utilized to target features of the entire many-body spectrum, a capability without which calculations of this kind would not be possible. The approach detailed represents one of the first utilized to compute these corrections in ab initio nuclear theory.

Speaker: Mr Michael Gennari

183 Studying nuclear matter under extreme conditions using supercomputing

The study of the Quark-Gluon Plasma (QGP) – the most extreme state of nuclear matter produced in relativistic heavy-ion collisions – has seen great progress in recent years, owing to advances in theoretical understanding, better experimental facilities, as well as the increase in computational resources available in modern High-Performance Computing (HPC) facilities. This talk will describe the crucial role HPC resources have played constraining long- and short-range QGP properties, while providing an outlook for future progress.

Long-range properties of the QGP fluid itself, such as its viscosity, have been constrained using low-energy hadrons measured at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory and the Large Hadron Collider at CÉRN [1]. The data from RHIC and LHC is also used to constrain short-range properties of the QGP, which are probed by studying how high-energy jets propagate through the QGP. Recently, the transverse momentum diffusion coefficient associated with jet-medium interactions has been constrained using a vast ensemble of data [2]. For both sets of QGP transport coefficients, large-scale HPC allocations deployed for Bayesian model-to-data comparisons were necessary. The next generation of Bayesian analysis will attempt to simultaneously constrain short- and long-range QGP transport coefficients, requiring an even greater effort from the nuclear physics community. Indeed, this endeavor will require larger involvement from computational/data physicists as well as significant HPC allocations. This increased participation of computational/data physicists in modern nuclear physics is a recognized need by the wider nuclear research community [3], and I will discuss potential interdisciplinary progress that can be made.

[1] D. Everett et al., Phys. Rev. Lett. 126 (2021) 24, 242301
[2] R. Ehlers et al., arXiv:2408.08247
[3] A. Boehnlein et al., arXiv:2501.00905

Speaker: Prof. Gojko Vujanovic (University of Regina)

184 Jet broadening and photon production in a viscous Quark-Gluon Plasma

Relativistic heavy-ion collisions form a quasi-free system of quarks and gluons known as Quark-Gluon Plasma (QGP). In addition to the formation of the QGP, these collisions also create high-momentum quarks and gluons, which will subsequently radiate a collimated spray of particles called a jet. The dynamical evolution of jets is well understood in electron-positron as well as proton-(anti) proton collisions; thus, jets act as a calibrated probe to study the QGP. The scattering rate of quarks and gluons in the jets within an inviscid (ideal) and viscous QGP fluid will be computed, allowing the use of jets to constrain the viscosity of the QGP. The theoretical formalism developed herein will be extended to study high-energy photon production within ideal and viscous QGP.

Speaker: Hemanth Regi (University of Regina)

(DQI) T2-7 | (DIQ)

185 Quantum algorithm for the gradient of the logarithm-determinant

An efficient implementation of the quantum gradient of the logarithm-determinant is demonstrated. The algorithm is shown to compare with existing methods on the quantum computer and scale more favourably, exposing that the key component for this algorithm is the wavefunction preparation step, as expected. Outlook for implementation and future extensions will be discussed, as will potential applications.

This research was undertaken, in part, thanks to funding from the Canada Research Chairs Program. This work has been supported in part by the Natural Sciences and Engineering Research Council of Canada (NSERC) under grant RGPIN-2023-05510.

Speaker: Thomas Baker (Department of Physics & Astronomy and also of Chemistry, University of Victoria)

186 Introducing the Partial Strassen Algorithm for entanglement renormalization

It is possible to formulate quantum states from the perspective of quantum information. Decomposing the wavefunction into a tensor network is dependent on the amount of entanglement in the wavefunction, implying for more strongly correlated quantum states that the problem becomes more and more expensive. All of the tensor operations can be formulated in terms of matrix operations, which must be efficient in order to solve problems. Traditional matrix multiplication runs in O(n^3), while the theoretical Strassen algorithm computes matrix multiplication in O(n^2.81) time. Unfortunately, constant factors become so large in the Strassen algorithm that it is impractical. There do exist practical variants however. We will present our findings on these variants, their advantages, and disadvantages.
A novel algorithm for matrix multiplication based on the Strassen equations, called the Partial-Strassen algorithm, will be presented. This new variant has the advantages that (1) memory consumption grows with input size only and not the additional parameter of depth k, and (2) for large matrices of dimension n and sufficiently large k the algorithm converges to running in O(n^3) time but more favourably than regular matrix multiplication in all cases. We will present our computational findings and the implementation steps required to obtain the largest theoretical speed up. Then we will cover the regime in which this algorithm is applicable.

A.D.~acknowledges support from the Undergraduate Student Research Award (USRA) from NSERC, the NSERC CREATE in Quantum Computing Program, grant number 543245, the Jamie Cassel's Undergraduate Research Award (JCURA). This research was undertaken, in part, thanks to funding from the Canada Research Chairs Program. This work has been supported in part by the Natural Sciences and Engineering Research Council of Canada (NSERC) under grants RGPIN-2023-05510 and DGECR-2023-00026, and ALL-RP 590857-23.

Speaker: Aaron Dayton (University of Victoria)

187 Quantum-assisted generative AI for simulating high-energy calorimetry

The quest towards probing the Higgs field in the High luminosity Large Hadron Collider (LHC) comes with many great challenges. In particular, the need to speed up the particle-detector simulations poses a roadblock, as projections show millions of CPU-years required to create simulated datasets. To tackle the problem of simulating particle-calorimeter interactions in the ATLAS detector at LHC we have developed a quantum-assisted deep generative model by combining quantum simulations with deep learning. In particular, we utilize D-wave’s Zephyr quantum annealer (QA) topology as a latent space prior using a variational autoencoder. We propose a robust method to generate conditioned samples using the quantum annealer leveraging flux bias to effectively increase the magnitude of the self-fields-to-interaction-energy ratio in the QA. We further propose a new, fast and robust method to estimate the effective inverse temperature in QAs. To benchmark our framework we use the CaloChallenge dataset, which has served as a catalyst for generative AI in high-energy calorimetry simulations. We compare our framework with 17 other frameworks which use generative AI and show that our framework is among the fastest and best in quality. The speed-up is three to six orders of magnitude compared to first-principles simulations used at CERN. We further assess the computational efficiency of our model in comparison to state-of-the-art generative models and first-principles approaches, demonstrating its potential for significantly accelerating high-energy physics simulations.

Speaker: J. Quetzalcoatl Toledo-Marin (TRIUMF)

188 Quantum entanglement in symmetric spin systems

We present a method to quantify entanglement in mixed states of highly symmetric spin systems. Symmetry constrains interactions between spins and predicts the degeneracies of the states. While symmetry alone produces entangled eigenstates, the mixed state (density) which contains all of the eigenstates (weighted by their Boltzmann factors) is not necessarily as entangled as the eigenstates themselves because generally the density can be re-expressed as a sum over states which are less entangled. The entanglement of the density is the minimum obtained by considering all such re-expressions, but there is no well-defined method to do this in general. Our method uses symmetry to explicitly construct unentangled contributions to the density, which are then optimally included in the density, resulting in a quantitative measure of entanglement that correctly accounts for the reduction of entanglement arising from degenerate states. We present results for several small spin systems.

Speaker: Stephanie Curnoe (Memorial Unversity of Newfoundland)

189 Invited Talk by Fabrice Retiere

awaiting abstract submission

Speaker: Fabrice Retiere (TRIUMF)

(DPP) T2-8 Plasma Material Synthesis | Synthèse de matériaux par plasma (DPP)

190 PLASMA DENSITY ENHANCEMENT EFFECTS DURING PLASMA IMMERSION ION IMPLANTATION

Plasma density enhancement is common during plasma immersion ion implantation (PIII) processes [1]. This effect manifests itself as a significantly increased current density to the target. The enhanced plasma density presents issues for accurate dosimetry in plasma ion implantation processes. Plasma density enhancement can be modelled using an empirically determined density enhancement factor [2] but a first-principles approach would be preferable. This paper discusses the mechanisms leading to plasma density enhancement and their modelling in the context of PIII processes. Consequences of this effects for accurate dosimetry in PIII systems and their various applications including semiconductor processing and fusion materials testing will be discussed.

1. B. P. Cluggish and C. P. Munson, “Secondary electron enhanced discharges in plasma source ion implantation”, J. Appl. Phys. 84, 1998, pp. 5945-5955.

2. S. Qin, M.P. Bradley, P.L. Kellerman, and K. Saadatmand, “Measurements of secondary electron emission and plasma density enhancement for plasma exposed surfaces using an optically isolated Faraday cup”, Rev. Sci. Inst. 73, 2002, pp. 1153-1156.

Speaker: Michael Bradley

191 Optimization of Target Utilization in Planar Circular Sputtering Magnetron Using PIC-MCC Modeling

This study investigates the optimization of target utilization, defined as the ratio of the total sputtered mass at the target's end-of-life to its initial mass, in a 3" planar circular sputtering magnetron. The study is conducted by modeling the ion bombardment process and predicting the resulting sputtering behavior. A self-consistent, axisymmetric 2D-3V Particle-In-Cell Monte Carlo Collision (PIC-MCC) model is implemented to simulate the generated plasma discharge properties and the effects of ion bombardment on the target surface.

A unique feature of the model is the dynamic management of the target shape using a pixelated approach, where the cathode consists of a set of target volume elements (pixels) that are progressively removed based on the sputtering profile calculated from ion bombardment. This allows for the estimation of sputtered mass and the calculation of the target mass ratio at the target’s end-of-life compared to its initial state. Various magnetic field configurations were studied, and a prototype magnetron was built using the configuration that provided the best utilization. Experimental measurements of target utilization for this prototype revealed an efficiency greater than 40%. Plasmionique Inc. is now commercializing this magnetron and continues to use this code for the ongoing development of its magnetron series. These results demonstrate the model’s potential to optimize magnetron design, offering significant time and cost savings by reducing the need for extensive experimental testing and prototyping.

Speaker: Noureddine Oudini (Plasmionique Inc)

192 Azimuthal and axial structures in 3D Particle-in-Cell simulation of Penning discharge

We report the results of 3D particle-in-cell simulations of cylindrical Penning discharge in the so called reflex configuration with the cathode and anti-cathode biased to the same negative potential. The discharge is supported by thermionic electron emission from the cathode. Electron and ion collisions, including ionization, are fully included. The emphasis is on a specific regime in which plasma potential in the center of the discharge is positive with respect to the chamber walls serving as an anode. We observe azimuthally rotating structures overlapping with the axial fluctuations that are weakly correlated with the azimuthal modes so that the azimuthal modes rotate as a whole and do not show any axial shear. Spatial and temporal scales of the observed structures and fluctuations are characterized. The mechanisms of the underlying instabilities are suggested and discussed.

Speaker: Mina Papahn Zadeh (Ph.D. candidate of Department of Physics of university of Saskatchewan)

193 Extended Materials Science look at MPCVD NV centers

The magnetic-field-dependent fluorescence properties of NV$^{-}$ center defects embedded within a diamond matrix have made them a candidate for solid state qubits for quantum computing as well as magnetic field sensing. Microwave plasma assisted chemical vapor deposition (MPCVD) of diamond with \emph{in situ} nitrogen doping has provided reproducibility and uniformity in the production of NV$^{-}$ centers on multiple substrates[1]. What has yet to be understood is the impact of the nitrogen doping time on the MPCVD process and its impact on the creation of NV$^{-}$ centers.
Analysis of the NV$^{-}$-containing diamond films has been carried out using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Raman spectroscopy, Photoluminesence spectroscopy, and optical microscopy. In addition, calculated plasma parameters and models have been used to quantify the properties of the MPCVD process.This study aims to investigate the effect of nitrogen doping time and its effect on the produced spectral lines associated with the 1333 cm$^{-1}$ Diamond Raman spectra peak, 637 nm photoluminesence NV$^{-}$ spectral peak, and the <111> and <220> diamond XRD peaks. A quantifiable/measurable relationship between spectral peaks, NV$^{-}$ density, and nitrogen doping time in terms of MPCVD process parameters is presented.

Speaker: William Davis (University of Saskatchewan)

194 Partial Equatorward Closure of Region 2 Birkeland Currents

The classic picture of the Birkeland current system includes a poleward (R1) and an equatorward (R2) sheet at most local times [Iijima and Potemra, 1976a], with an additional poleward sheet near noon [Iijima and Potemra 1976b] and midnight (in the Harang region). Away from noon and midnight, the R1/R2 currents are generally considered to form a nearly-balanced pair, with a fraction of the R1 currents closing across the polar cap, and R2 comprising the Birkeland system’s equatorward boundary. However, using precise magnetic field measurements from ESA’s Swarm satellite mission, we find that a significant fraction of auroral zone traversals display evidence of an additional sheet equatorward of R2, occurring at all local times, and having the opposite polarity of R2, indicating partial closure of the R2 sheet in the equatorward direction. In this presentation we explore their dependence of these “Region 3” currents on local time, magnetic activity level, and other parameters.

Speaker: Yihenew Getu (University of Calgary)

(PPD) T2-9 Particle physics at colliders I | Physique des particules aux collisionneurs I (PPD)

195 Recent Highlights in Higgs Physics with the ATLAS Experiment

The discovery of the Higgs boson in 2012 by the ATLAS and CMS experiments at the Large Hadron Collider (LHC) marked a major milestone in particle physics. Since then, Standard Model (SM) Higgs processes have been studied with unprecedented precision, extending into kinematically challenging regimes and rare production and decay modes. These precision measurements not only test the SM but also offer a promising avenue to constrain new physics effect through the Effective Field Theory (EFT) approach. Some of the measurements also shed light on key Higgs properties, including its charge-parity (CP) structure and total decay width. This talk presents recent Higgs boson measurements from the ATLAS experiment using Run-2 and Run-3 data, spanning multiple decay channels and production modes, and highlights the diverse analysis strategies employed by these analyses.

Speaker: Jiayi Chen (Simon Fraser University (CA))

196 Effectively Exploring New Physics: EFT interpretation of ATLAS Run-2 data on the WZ → llνl channel

In the framework of the Standard Model Effective Field Theory (SMEFT), the Standard Model can be seen as a low-energy approximation of a deeper, more fundamental theory that introduces new heavy particles at a higher energy scale, $\Lambda$. By integrating out these beyond-the-Standard-Model (BSM) particles, SMEFT offers a model-independent way to describe their potential effects.

This talk focuses on electroweak processes involving the coupling of the and $W$ and $Z$ bosons, where both bosons decay into leptonic final states. These processes provide a key window to probe anomalous triple gauge couplings (aTGCs), which could hint at physics beyond the Standard Model. The ATLAS Run-2 dataset, with 139 fb$^{-1}$ of data, offers a powerful opportunity to explore these effects.

This talk will present 1D constraints on the SMEFT operators most sensitive to these interactions, as well as novel 2D limits that constrain pairs of SMEFT operators simultaneously. These results help us better understand potential deviations from the Standard Model and bring us one step closer to uncovering new physics.

Speaker: Maheyer Jamshed Shroff (University of Victoria (CA))

197 Machine learning techniques for mass-independent event classification in a search for singly- and doubly-charged Higgs bosons with ATLAS at the LHC

In 140$~$fb$^{-1}$ of proton-proton collision data recorded by the ATLAS detector in Run 2 of the LHC, an excess was observed in both the W$^{\pm}$Z and W$^{\pm}$W$^{\pm}$ channels with a combined global significance of 2.5 standard deviations. This excess could be attributed to the production of singly- and doubly-charged Higgs bosons, which are hypothesized by the Georgi-Machacek$~$(GM) model. To investigate this excess and assess its compatibility with the GM model, a dedicated search is being performed for the GM H$^{\pm}$ and H$^{\pm\pm}$ where they decay to W$^{\pm}$Z and W$^{\pm}$W$^{\pm}$ respectively. Optimizing a signal region sensitive to this new physics model is complicated by two key factors. First, there are many background sources including QCD and EW processes with W and Z bosons in the final state which have similar kinematic distributions to signal. Second, there is significant variability in the kinematics of the signal process since the search for the singly- and doubly- charged Higgs bosons is being performed across a range of masses from $200~\textrm{GeV}$ to $3~\textrm{TeV}$. To address these challenges, a neural network (NN) was trained to discriminate signal events from background events in each of the W$^{\pm}$Z and W$^{\pm}$W$^{\pm}$ channels. It was observed that the weighting of mass points used in training impacts the classification performance across the mass range and can be used to customize the analysis sensitivity to different mass regions. Various methods for attributing systematic uncertainties to the NN classification were also explored. The neural network scores were used to define new W$^{\pm}$Z and W$^{\pm}$W$^{\pm}$ signal regions, and this was found to improve the exclusion limits compared to a cuts-based approach.

Speaker: Adrienne Jean Scott (University of Victoria (CA))

198 Low mass visible dark photon search at Belle II

The Belle II experiment has accumulated 575 fb⁻¹ of data from the SuperKEKB asymmetric electron-positron collider. We present the current status of the search for low-mass dark photons (A′) from $e^+e^- \rightarrow A'\gamma \rightarrow e^+e^-\gamma $reaction based on collision data recorded by the Belle II experiment. The dark photon is a hypothetical gauge boson that would appear as a narrow resonance in the electron-positron invariant mass spectrum. This analysis targets masses ranging from the electron pair production threshold up to the muon pair production threshold, with a particular focus on the sub-20 MeV region. This low-mass range is of special interest due to the presence of the X17 anomaly and the lack of strong constraints on the kinetic mixing parameter ($\epsilon$). The major challenge in this mass region is the photon conversion background, which mimics the signal signature. Belle II’s high-luminosity dataset and excellent vertex reconstruction capabilities provide enhanced sensitivity in this difficult low-mass regime. To mitigate background contamination, we employ a Boosted Decision Tree (BDT) classifier that leverages advanced features derived from vertex fitting. The trained model was validated using radiative dimuon events with a photon conversion $e^+e^-\rightarrow \mu^+\mu^-\gamma \rightarrow \mu^+\mu^-[\gamma \rightarrow e^+e^-]$. We will present the event selection criteria, validation and optimization strategies, and preliminary sensitivity projections based on Monte Carlo simulations.

Speaker: Ijeong Na (University of Manitoba)

199 Shining (Dark)Light on Interactions with the Dark Sector

Despite dark matter’s existence and high abundance in our universe being well supported by cosmological evidence, our current understanding of it is limited due to the lack of observations of dark matter interactions on the particle scale. If and how the Standard Model interacts with the dark sector remains a major open question in particle physics. The DarkLight experiment attempts to reconcile the apparent disconnect between the two sectors through the search for a postulated particle, known as the dark boson, which would mediate interactions between the Standard Model and the dark sector. Based at the TRIUMF superconducting electron linear accelerator, DarkLight aims to produce Standard Model photons and dark bosons from the interaction between an energetic electron beam and a thin high Z target, then measure the momentum of the electron/positron pairs produced in the decay of these particles. By reconstructing the invariant mass of each electron/positron pair’s parent particle, a bump hunt can be conducted on the invariant mass distribution. Specifically, DarkLight will be searching for a dark boson in the 10-20 MeV mass range. The DarkLight experiment will provide critical information to the global dark boson search by probing regions of parameter space yet-to-be explored by a lepton based experiment. This talk will discuss the status and upcoming milestones of the DarkLight experiment as the collaboration prepares for the first experimental run, set to take place this year. Particular focus will be given to the capabilities and utility of the DarkLight trigger system; a core responsibility of the Canadian branch of DarkLight.

Speaker: Gabby Gelinas (UBC/TRIUMF)

15:45 Health Break with Exhibitors | Pause santé avec les exposants

(DQI) T3-1 | (DIQ)

(DTP) T3-10 Particle Physics and Field Theory | Physique des particules et théorie des champs(DPT)

200 Feynman symmetries and graph invariants

Many identities between Feynman integrals can be understood graph theoretically. We can also ask about other graph invariants with these same symmetries and ask what they look like mathematically and what they tell us back about the Feynman integrals. I will talk concretely about some such invariants and these questions.

Speaker: Karen Yeats (University of Waterloo)

201 Classical Hilbert space, statistical mechanics and gauge freedom

The Koopman-von Neumann (KvN) formulation brings Hilbert space to classical mechanics, and has applications from dynamical systems to quantum-classical interaction.  The formulation, however, has not been exploited to its full extent.  We show that the existence of a family of extensions to the KvN equation allows for the derivation of the canonical ensemble distribution through simple separation of variables.  This indicates that certain assumptions of statistical mechanics translate into simple statements in the KvN formulation.  Further, we show a procedure for constructing an orthonormal set of vectors in that Hilbert space for arbitrary phase-space regions, and a procedure for forming non-trivial superpositions across solutions to the family of extended KvN equations.  Finally, we show that the spectrum of the Liouvillian operator comprises relevant physical quantities, and the connection is found through the canonical conjugate of the Hamiltonian.  This helps interpret and give meaning to variables often dubbed "extra" or "auxiliary" in the KvN formulation.

Speaker: Mr Mustafa Amin (University of Lethbridge)

202 Probing quark-gluon plasma using photons

Ultra-relativistic heavy-ions collisions performed at the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC) produce a deconfined state of quarks and gluons, called the quark-gluon plasma (QGP). One of the primary goals of these collisions is to infer the properties of the QGP through the modifications it imparts on the evolution high-energy quarks and gluons (also known as hard partons) in the QGP. At early times following a heavy-ion collision, partons are produced in a highly excited (i.e. highly virtual) state and undergo energy loss via bremsstrahlung radiation. At later times, multiple scatterings in the QGP become the dominant mechanism of parton energy loss. To better understand the dynamics of the parton energy loss, we focus on the production of photons from the highly virtual hard quarks traversing the QGP. In prior efforts, scattering rates have been computed for the case of gluon bremsstrahlung off from a highly virtual quark traversing the QGP. To minimize hadronization uncertainties, the present study focuses on photon emission rates. Photons avoid hadronization effects and provide an independent probe to constrain the parton energy loss transport coefficients.
We used the generalized factorization procedure, employed in the e-A deep-inelastic scattering, to derive an improved single emission and single scattering collision kernel for photon production, going beyond traditional in-medium gluon exchange approximation. We identified four types of scattering kernels at $O(\alpha_{em}\alpha_{s})$ giving the following final states: (i) real photon and real quark, (ii) real photon and real gluon, as well as virtual photon corrections to (iii) quark-antiquark production and (iv) quark-quark production. We will present these four scattering kernels [1] and argue that a better way to extract properties of the QGP is to simultaneously use photons and jets.

Reference:
(1) A. Kumar and G. Vujanovic, arXiv:2502.02667 (2025)

Speaker: AMIT KUMAR (Department of Physics, University of Regina Canada)

203 Sufficient is better than optimal for training neural networks

As the 2024 Nobel Prizes highlight, neural networks have emerged both as an important physical paradigm, and for representing complex phenomena beyond physics. The fidelity of neural network representations of complex phenomena relies on a fundamental tension between universality and generalizability. In this talk, we will argue that, for neural network training, optimization is the enemy of generalizability. We will show that reframing neural network training in physical terms opens new paths to generalizable networks. We will describe an alternative set of training algorithms that exploit the mathematical physics of filters. Using arguments from information geometry, we will show that filter-based training algorithms yield a set of "sufficient training" methods that outperform optimal training methods, e.g., Adam. We will show that sufficient training can be used to "retrofit" networks that were overfit by optimal training. We will give examples where sufficient training improves generalizability when deployed from the outset. We will describe an open-source implementation of sufficient training we term "simmering". Using these results we will make the case that maintaining physical perspectives on neural networks is pivotal for their continued application to complex phenomena in physics and beyond.

Speaker: Prof. Greg van Anders (Queen's University)

(DASP) T3-2 Middle Atmosphere dynamics, observations, climate, and modeling | Dynamique de l'atmosphère moyenne, observations, climat et modélisation (DPAE)

204 The Keystone Mission: Concept and Objectives

The Keystone mission is one of four mission ideas selected for assessment study as a potential mission for ESA’s Earth Explorer 12. It targets the observations of atomic oxygen, composition, temperature and wind in the mesosphere and lower thermosphere. The mission concept is currently being developed through an assessment study undertaken by a Mission Advisory Group (co-authors above) led by Daniel Gerber and supported by an ESA Core Team. The intent of this mission is to provide comprehensive observations (day/night) over a broad range of conditions. The processes involved in the energy and constituent balances can be specified and understood in more detail than currently possible. In this talk the mission concepts and objectives will be introduced along with a summary of the ESA mission selection process.

Speaker: William Ward (University of New Brunswick)

205 Modulation of Terrestrial Lightning Rates by Solar Sector Crossings: Evidence of 14 Day Periodicity of Lightning Rates in the Continental United States

A small number of studies, principally conducted using lightning data from the UK, have suggested that a connection exists between solar wind magnetic structure and terrestrial weather phenomena. Following these earlier studies, we investigate the hypothesis that there may be a connection between lightning rates and changes in polarity of the heliospheric magnetic field (HMF) by using data from larger and different geographic regions on the Earth. In this study, we use World Wide Lightning Location Network (WWLLN) data spanning the years from 2010-2021. Using Lomb-Scargle periodograms, we demonstrate evidence of a statistically significant 14-day periodicity in lightning activity across the continental United States. A strong 14 day periodicity is also evident in the y component of the HMF. This indicates that there could be a connection between the lightning rates and HMF polarity, and in particular associated with heliospheric current sheet crossings. To further study this phenomenon, we applied a superposed epoch analysis (SEA) to daily averaged rates of lightning. The zero epochs were defined by solar wind sector crossings, defined by state changes in the polarity of the y component of the HMF, such traversals lasting several days. Initial results from this analysis point to the modulation of lightning rates by polarity changes of the HMF, this being validated by the lightning data for the continental United States. Currently, we are analysing other geographic locations including Europe to test if this modulation of lightning rates and periodicity hold in other geographic regions, and how this might be further affected by changes to the number and coherency of heliospheric current sheet crossings at different times and/or phases of the solar cycle.

Speaker: Jennifer Peterson (University of Alberta)

206 Simulated Changes in Large-scale Atmospheric Circulation Energetics from Volcanic Aerosol Forcing

Understanding the response of large-scale atmospheric circulation to radiative forcing agents is important for climate prediction. The radiative forcing from volcanic stratospheric aerosol is one of the most important natural climate forcings, with impacts on surface temperature and atmospheric dynamics. In this study, we explore changes in the energetic properties of the Hadley and Ferrel systems under the influence of radiative forcing associated with large volcanic eruptions in multi-model simulations performed as part of the Model Intercomparison Project on the Climatic Response to Volcanic Forcing (VolMIP) within the Coupled Model Intercomparison Project Phase 6 (CMIP6). In the Earth’s atmosphere, the Hadley and Ferrel systems are examples of thermally direct (warm air rises and cold air sinks) and indirect (cold air rises and warm air sinks) circulations, respectively. Being the part of Lorenz cycle of energy transformation in the atmosphere, the direct circulation converts zonal-mean available potential energy into zonal-mean kinetic energy. The indirect circulation in the midlatitude, however, converts some of the zonal-mean kinetic energy back into zonal-mean available potential energy. Averaged over the 4 models that provided the required model output from the VolMIP Pinatubo simulations, the mean power associated with the Hadley system in preindustrial simulations is 235.6 TW. The mean decrease of the power in VolMIP simulations of the 1991 Pinatubo eruption is 7.58 TW (3.22%) for the first post-eruption northern-hemisphere (NH) winter and 6.59 TW (2.80%) for the second one. For the Ferrel system, the preindustrial mean DJF power is 326.10 TW, and post-volcanic anomalies are 16.3 TW (5.00%) and 18.3 TW (5.61%) in NH winters 1 and 2, showing a stronger anomaly in the second NH winter than the first one. In additional VolMIP experiments, we also explore the response of the Hadley and Ferrel cells to the relatively strong forcing associated with the 1815 Tambora eruption and find the Hadley system weakening by 15.3 TW (6.48%) and 11.5 TW (4.90%) for the first two NH winters. We explore how post-eruption changes in the meridional atmospheric circulation strength and the cells' location can be explained with simple theoretical models of atmospheric thermodynamics.

Speaker: Anatoly Poroshenko (University of Saskatchewan)

207 The feasibility of a CubeSat-sized ozone-profiling satellite instrument

The Optical Spectrograph Infrared Imager System (OSIRIS) is an imaging spectrometer developed by researchers at the University of Saskatchewan that is currently on board the Swedish Odin satellite. OSIRIS conducts ozone measurements of the atmosphere by measuring the spectrum of limb-scattered sunlight, which are then later processed to retrieve vertical atmospheric profiles of ozone. Since the launch of OSIRIS, CubeSat missions are increasingly becoming commonplace for use in Earth-atmosphere science and remote sensing. However, CubeSat missions that perform remote sensing or Earth-atmosphere experiments typically conduct observations in nadir geometry, and very few CubeSat missions to date use the limb geometry for these observations. There are currently no ozone CubeSat missions in development that measure ozone in the limb geometry. This presentation will discuss the feasibility of a CubeSat-sized ozone-sensing instrument in the limb geometry. Results from retrieval simulations that use an instrument model and a radiative transfer model to simulate a 12U, 6U, and 3U sized OSIRIS payload will be discussed.

Speaker: Waseem Tannous (University of Saskatchewan)

CAP2025125050_ContributorsFullListV1.bib

CAP_Abstract.docx

208 Investigating Microwave Emission Variability in Snow using Artificial Neural Network Retrievals and the Improved Born Approximation

Snow cover plays a crucial role in Earth's energy budget as both a reflective and insulative material. Accurately representing snow properties in climate models and weather forecasts is challenging due to their high spatial and temporal variability, which is particularly important in the polar regions. This variability affects microwave radiative transfer, leading to significant uncertainties in satellite retrievals, reanalysis products, and climate models. However, passive microwave satellite measurements provide valuable insight into snowpack properties by capturing radiation at multiple frequencies, each with different penetration depths.

This study compares frequency-dependent effective surface temperatures retrieved from Advanced Technology Microwave Sounder (ATMS) brightness temperatures using an Artificial Neural Network (ANN) to model simulations based on the Improved Born Approximation (IBA). The IBA offers a physically consistent framework for modelling microwave interactions in snow by accounting for both absorption and multiple scattering within a granular medium. By comparing ANN retrievals to IBA-modelled brightness temperatures, this work explores what can be learned about snow microstructure and its impact on microwave radiative transfer. Ground-based observations from the Cold Regions Research and Engineering Laboratory (CRREL) ice mass balance buoys and the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition are used for validation.

This analysis provides insight into how ANN-based retrievals can capture the complex variability of snow properties and assesses their potential for improving microwave-based observations of polar regions, which could, in turn, improve climate modelling of these regions.

Speaker: Colleen Henschel (Dalhousie University)

(DAMOPC) T3-3 Rydberg Atoms and Radiative Transfer | Atomes de Rydberg et transferts radiatifs (DPAMPC)

209 High precision theory for the Rydberg states of helium up to n = 30: a critical test of QED

Recent measurements for the ionization energies of the Rydberg singlet-P and triplet-P states of helium for principal quantum number $n = 24$ to 100 [1] present a new challenge to high-precision atomic theory. A long-standing obstacle is that the accuracy of variational calculations for two-electron systems rapidly declines with increasing $n$. The problem has now become urgent with the publication of the Clausen et al. measurements. We will present new variational techniques that allow high-precision results to be extended as high as $n = 30$ [2], thereby setting a new record of accuracy for high-lying Rydberg states. The combination of theory and experiment provides absolute points of reference for transitions to lower-lying states where there is an $8\sigma$ disagreement between theory and experiment. Relativistic and quantum electrodynamic (QED) corrections are included by perturbation theory up to order $\alpha^5mc^2$. Higher-order QED uncertainties are strongly suppressed due to their $1/n^3$ scaling, thereby resulting in total theoretical uncertainties as low as $\pm$2 kHz.
[1] G. Clausen et al., Phys. Rev. A 111, 012817 (2025).
[2] A. Bondy et al., Phys. Rev. A 111, L010803 (2025).

Speaker: Gordon Drake (University of Windsor)

210 Superradiance and Subradiance in Astrophysics: Rethinking Light-Matter Interactions

Astrophysical radiative transfer models typically assume that atoms and molecules emit and absorb radiation independently. However, recent evidence suggests that cooperative quantum effects—such as superradiance and potentially subradiance—can significantly alter radiative behavior.

Superradiance, a cooperative quantum emission process, has been observed in star-forming regions, where it coexists with maser activity and challenges traditional density estimates based on spectral lines. I will present observational evidence and discuss its astrophysical implications.

Additionally, subradiance-where radiation is reduced due to quantum interference-has been theoretically predicted in astrophysics and may also influence absorption processes in certain environments. While direct observational evidence is yet to be established, subradiance could provide insights into anomalous densities and deviations from classical radiative transfer models.

By moving beyond traditional assumptions, we can gain a deeper understanding of light-matter interactions, quantum coherence, and the limitations of standard radiative models in space.

Speaker: Dr Fereshteh Rajabi (McMaster University)

17:15 Discussion / Networking

(DCMMP) T3-4 Special Session - Physics, Climate change, and the transition to sustainability / Physique, changement climatique et transition vers la durabilité (DPMCM)

211 Clouds in a warmer climate

Shallow cumulus and stratocumulus clouds over open ocean surfaces play a crucial role in Earth's energy and radiation budget. These clouds are highly reflective and strongly influence the planet's temperature. While stratocumulus clouds generally exert a cooling effect by reflecting solar radiation, their response to a warming climate is complex. Some studies suggest that stratocumulus cloud cover may decrease with warming, potentially amplifying climate change rather than mitigating it. Shallow cumulus clouds also interact with climate processes in ways that introduce significant uncertainties in climate projections.

Understanding cloud-climate interactions remains a challenge due to the multiscale nature of cloud processes, which range from micrometer-scale droplet interactions to cloud formations extending over thousands of kilometers. Small-scale cloud processes are not explicitly resolved in climate models and require parameterization, while large-scale atmospheric dynamics strongly influence cloud evolution and behavior.

In this presentation, we focus on shallow cumulus clouds over subtropical and Arctic oceans. Using observational data, we construct idealized vertical profiles adapted to warmer climate scenarios. These profiles serve as a basis to investigate cloud microphysics, structural changes, and potential feedback mechanisms in a warming climate, using the nonhydrostatic, convection-resolving Cloud Model 1.

Speaker: Lisa Schielicke (Western University)

212 Global Environmental Measurement and Monitoring

To best adapt to climate change, we need to accurately predict the climate along with its effects on the earth. This of course is an incredible challenge that we are facing and requires a more extensive
network of environmental measurements of the atmosphere, geosphere, cryosphere, hydrosphere and biosphere than can be currently achieved. To help spur the development of needed environmental measurements, Optica in collaboration with AGU has launched the GEMM initiative. The GEMM
initiative is focusing on having scientists and engineers working across disciplines both in sensor technologies and environmental science collaborate. GEMM is also bringing together scientists and public policy makers for better communication and a more effective response to the new challenges imposed by climate change. At the University of Waterloo, we have recently launched a new GEMM node. We have explored starting a Canada wide GEMM initiative.

Speaker: Donna Strickland (U Waterloo)

(DPP) T3-5 Laser Plasma Interaction & Complex Plasmas | Interaction laser-plasma et plasmas complexes (DPP)

213 Study of solid to plasma transition of Warm Dense Matter generated by ultrashort laser pulses

Materials under high intensity femtosecond laser irradiation yield extreme material conditions called warm dense matter (WDM) with thermal energy comparable with the Fermi energy and the ion-ion coupling parameter exceeding unity. The WDM state exists in a variety of processes ranging from laser micromachining to inertial confinement fusion experiments. The WDM exists as transient states including as nonthermal WDM in the first few hundred femtoseconds when the electron thermalization is important and as two temperature WDM with initially high electron temperature and relatively low ion temperature. The initial electron temperatures depend on its heat capacity. Subsequently, the electron temperature would fall and the ion temperature would increase subsequently the WDM transits into the plasma state (typically called laser ablation). The rates of ion temperature increase depend on the electron-ion coupling. We have used pump-probe techniques to study WDM produced by irradiating few ten's of nanometers thick free-standing metal foils with high intensity femtosecond laser pulses. In this talk, I will present the results of electron heat capacity and electron-ion coupling factor of the heated foils extracted from the measured optical conductivities. present the studies of dissemble and structural change processes of the heated foils using optical Frequency Domain Interferometry and Electron Diffraction techniques respectively. Finally, I will present the comparison of the experimental onset laser ablation times with predictions from several molecular dynamic (MD) simulations using different electron heat capacity and electron-ion factor values to illustrated these two parameters play important role in modeling ultrafast laser ablation using MD models.

Speaker: Prof. Ying Tsui (University of Alberta)

214 Canada’s Magnetic Confinement Fusion (MCF) Devices – MU Z-pinch and STOR-M tokamak

While holding the promise of meeting the large energy demands of the future, a practical energy producing fusion reactor has eluded humanity since it’s conception in the middle of the twentieth century. The difficulty can be partially attributed to the complicated behaviours of a plasma, the medium where fusion reactions take place. This talk will provide a theoretical framework and an overview of the concepts of magnetic confinement fusion (MCF) used in two Canadian MCF devices oriented towards fusion applications, the MU z-pinch (Quebec) and STOR-M tokamak (Saskatchewan).

The MU Z-pinch is part of a new class of z-pinch devices which demonstrate neutron production and plasma stability 1-2 orders of magnitude longer than theoretical Alfven transit time, representing both a theoretical and experimental breakthrough. Z-pinch systems have a simplistic geometry, offering the possibility for lower cost fusion reactors as compared to tokamaks or stellarators. While previous studies have correlated stabilization of the m=0 “sausage” mode to a radial sheared flow profile this does not explain the stabilization for the m=1 “kink” mode. Experimental magnetic data from several arrays of diagnostic bdot probes are analyzed via time-of-flight and spatial Fourier analysis methods to infer several plasma phenomena including stabilization of the m=1 “kink”.

The STOR-M tokamak is a small experimental tokamak at the University of Saskatchewan operating since 1987. While the size and energy output of tokamaks continues to increase in the move towards breakeven/ignition, plasma disruptions may damage these large (and costly) tokamaks, relegating the study of plasma disruptions to either theory/simulations (for which there is not yet a comprehensive theory) or replicating conditions on smaller tokamaks. Rotating m=2 magnetic islands measured with an array of magnetic bdot probes have been found to precede minor plasma disruptions which are accompanied by a static m=1 mode in the STOR-M tokamak.

Speaker: Brad Dempsie (University of Saskatchewan - PhD Candidate)

CAP_2025_Abstract_and_Title_Brad_Dempsie_DPP.pdf

215 MHD Modeling of Plasma Flow and Acceleration in the Magnetic Nozzle

Open axisymmetric converging-diverging magnetic field configurations, such as magnetic nozzles and magnetic mirrors, are widely employed in various plasma systems for fusion and propulsion applications. Supersonic plasma acceleration and thrust are the quantities of interest in these configurations. We perform two-dimensional (radial-axial) ideal magnetohydrodynamic (MHD) simulations, with an emphasis on the acceleration mechanism including the electromagnetic effects and the effects of azimuthal plasma rotation. We show that near the axis (for small radii), supersonic plasma acceleration follows the predictions of the analytical theory in the low-pressure limit. The azimuthal plasma rotation and magnetic field provide additional energy that can be converted into the energy of the directed flow. Our simulations also include the effects of the radial pressure gradient and associated modifications to the background magnetic field due to finite plasma pressure.

Speaker: Nishka Sheth (University of Saskatchewan)

216 RARE ETA AND ETA-PRIME DECAY PROGRAM AT HALL D/JEFFERSON LAB*

Measurements of several rare η and η′ decay channels will be carried out with an upgraded GlueX detector in Hall D as part of the Jefferson Lab Eta Factory (JEF) program. JEF will commence in late March 2025: the combination of highly-boosted η/η′ production, recoil proton detection, and a new fine-granularity high-resolution lead-tungstate insert in the GlueX forward calorimeter confers uniqueness to JEF, compared to other experiments worldwide. JEF will search for new sub-GeV gauge bosons in portals coupling the Standard Model sector to the Dark sector, will provide constraints on C-violating/P-conserving reactions, and will allow precision tests of low-energy QCD. Simulations have been driving methods towards significant background reduction and signal isolation for key rare decay channels: the γp → ηp, η → π+ π− e+ e− channel will be shown as an example. Details on the hardware upgrade and initial look at the commissioning of the device will also be presented.

Speaker: MacQuarrie Thomson (University of Regina)

CAP 2025 - abstract-JEF.pdf

CAP 2025 - abstract-JEF.tex

217 Dust Injection in STOR-M

STOR-M (Saskatchewan TORus - Modified) is a small tokamak which began operation in 1987 and is currently the only operating tokamak in Canada. STOR-M’s core plasma parameters are similar to that of the edge region in modern tokamaks, such as WEST and ASDEX Upgrade. The most recent STOR-M campaigns have been dedicated towards plasma-dust interaction studies using pre-characterized tungsten microparticles. These campaigns are especially relevant, as tungsten is a primary wall material for future fusion reactors. Experiments begin with the injection of tungsten microparticles (dust) prior to the initiation of Ohmic heating, which occurs at a controlled delay time and determines the amount of in-vessel dust present in the discharge. Within the plasma, dust particles are heated and become incandescent, allowing for their observation with two fast cameras. Loop voltage, plasma current and discharge duration are some of the plasma parameters found to be detrimentally affected, proportional to an increased amount of dust within the plasma volume. Additionally, a strong toroidal force affects tungsten dust trajectories when a sufficiently small amount of dust is present. Doppler spectroscopy measurements further reveal that an increased amount of in-vessel dust reduces the acceleration of plasma ions within the core. The statistical mean net force on dust, measured from dust trajectories, was analyzed and compared to the Barnes and Hutchinson/Khrapak ion-drag force models [1]. It is found that the mean force acting on dust is systematically larger than predicted by either model, though within a factor of approximately 2-3. Plasma current reversal in STOR-M is found to change the direction of dust motion, which qualitatively supports an ion-drag model. Supplemental post-mortem sampling of dust in STOR-M indicates a substantial reduction in the sizes of dust particles measured downstream of the dust-injector (in the direction of plasma current), indicating selective transport of dust by size and/or ablation of the toroidally transported dust.

[1] André Melzer et al. Physics of dusty plasmas. Vol. 962. Springer, 2019.

Speaker: Nathan Nelson (University of Saskatchewan)

Nathan_Nelson_CAP_2025.pdf

(DNP) T3-6 Nuclear reactions | Réactions nucléaires (DPN)

218 Direct Measurements of Key Nuclear Reactions for Astrophysics Using DRAGON

Most elements observed in the galaxy are produced through nuclear reactions inside stars, including explosive stellar phenomena, such as classical novae, supernovae, and neutron star mergers. To understand galactic elemental abundances, it is essential to determine the rates of these reactions. Additionally, simulations of these astrophysical environments have shown that many predicted properties are highly sensitive to nuclear reaction rate uncertainties.

The ideal method for determining these reaction rates is through direct measurements. Such experiments are conducted using the DRAGON recoil mass spectrometer at TRIUMF. In this talk, I will present results from a recent DRAGON experiment to determine the yield curve of the $^7$Li(α,γ)$^{11}$B reaction close to $E_{CM} \sim 2.8$ MeV. Determining the rate of this reaction is important for understanding the abnormally large decay rate of the β$^-$-delayed proton decay of $^{11}$B and the production of $^7$Li and $^{11}$B in core-collapse supernovae. Additionally, I will present a new development where DRAGON was coupled with the DEMAND array of neutron detectors to directly study (α,n) reactions. These reactions are particularly important for the weak r-process in core-collapse supernovae and the s-process in AGB and massive stars. This measurement represents the first of its kind, introducing a novel approach for directly determining (α,n) reaction rates.

Speaker: Ben Reed (TRIUMF & Saint Mary's University)

219 Simulations to Determine the Material Properties of Diamond-like-carbon Coated UCN Guides

The TRIUMF Ultracold Advanced Neutron (TUCAN) Collaboration has recently built a surface coating facility at the University of Winnipeg. The primary purpose of this facility is to prepare ultracold neutron (UCN) guides to transport UCNs from source to an electric dipole moment experiment. The application of special coatings enhances UCN reflection and increases transmission through the guide system. The UCN guide coating facility specializes in coating diamond-like-carbon (DLC) onto the inside of cylindrical UCN guide tubes. Before implementing guides in the experiment at TRIUMF, each one must be individually tested to determine if there are any deficiencies in the coatings. In this talk, I will present results of PENTrack simulations of a neutron storage experiment at the Japan Proton Accelerator Research Complex (JPARC) UCN source to characterize the DLC-coated UCN guides. Comparing the experimentally determined and the simulated storage lifetimes of the JPARC experiment allows one to extract the material properties of a given UCN guide. Using this process, any UCN guide coated by TUCAN, or any other group can be evaluated for its efficiency in transporting neutrons.

Speaker: Thomas Hepworth (The University of Winnipeg)

220 Higher-Order Leptonic Corrections Using Covariant Approach

In order to search for physics beyond the Standard Model at the precision frontier, it is sometimes essential to account for higher-order radiative corrections. We perform complete and detailed calculations of electroweak radiative corrections to parity-violating lepton scattering with a distinguishable target (electron-proton,muon-proton) up to Next-to-Next-to-Leading Order (NNLO) level using a covariant approach. Our NNLO level corrections include quadratic and reducible two-loop level scattering amplitudes. In the covariant approach, we apply a unitary cut to the Feynman diagrams and separate them into leptonic and hadronic currents. After squaring the matrix elements, we contract the leptonic-hadronic currents and obtain the differential scattering cross sections up to NNLO level.
Our numerical results are presented at energies relevant for a variety of existing and proposed experimental programs such as QWEAK, P2, MOLLER (background studies), MUSE, and EIC working at the precision frontier. Analysis of these results shows that such corrections at the NNLO level are quite significant to consider at the theoretical level with the increasing precision of future experimental programs at low-energy scales.

Speaker: Ms Mahumm Ghaffar (Memorial University of Newfoundland)

221 A Measurement of the Neutron Spin-Polarization in Deuterium Photodisintegration

The force between nucleons, termed the nucleon-nucleon interaction or residual strong force, is wholly responsible for binding nucleons together to form atomic nuclei. Contemporary theories describing this interaction have been fitted to a wealth of nucleon-nucleon scattering cross sections with much success. This provides confidence to the various approaches when modelling this nuclear force, however, this is largely limited to unpolarized results. The polarization degrees of freedom within these interactions present an excellent opportunity to explore the richer dynamics of nuclear reactions.

Deuteron photodisintegration provides an excellent test case for investigating these quantities. The deuteron is the simplest and least energetic nuclear system, and the photon is well-understood through QED, allowing for the contributions of the nucleon interactions to be isolated. One such observable is the spin-polarization of the recoil neutron in deuterium photodisintegration. This quantity is of significant importance to nuclear physics, as there exists several discrepancies between historical measurements and theoretical calculations near the deuteron breakup threshold. Rectifying this inconsistency strengthens the understanding of the nuclear force.

Innovations in accelerator and detector technologies offer new capabilities to obtain precise results for deuteron photodisintegration. An experiment was conducted at the High-Intensity Gamma-Ray Source (HIGS) using a newly-developed detector array to measure the recoil neutron polarization by means of a spin-dependent scattering asymmetry. The experimental setup consists of a heavy-water target surrounded by polarization analyzers at several angles of interest, which themselves are surrounded by several liquid scintillation detectors. The photodisintegration neutrons undergo a spin-dependent scattering with Helium within the analyzers, and are then detected by the scintillators. The recoiling Helium nuclei are also detected, and a coincidence requirement is imposed between the signals. The measurement of a scattering asymmetry from these events directly correlates to the incident neutron polarization.

Included are the results from this investigation utilizing a circularly-polarized beam at energies of 8 and 16 MeV. This is a subset of a larger dataset that includes additional beam energies and polarizations.

Speaker: Tanner Polischuk (University of Hawaii at Manoa)

Polischuk_CAP_Abstract.pdf

(DPE-DQI) T3-7 Joint Session | Session Conjointe (DEP-DIQ)

222 Making the Quantum Leap: Experiments in Quantum Physics Education

Quantum mechanics is one of the central pillars of modern physics. However, for a variety of reasons - conceptual, mathematical, and philosophical - many students struggle to master this topic at the undergraduate level. In this talk, I will describe several ongoing projects at McMaster related to quantum physics education. I will present the preliminary results from our Upper Year Quantum Survey, a multi-year study which seeks to examine student (and instructor) attitudes towards the teaching and learning of quantum physics. I will then describe efforts to develop new hands-on demonstrations of quantum phenomena using neutron beams, a convenient example of wave-particle duality provided by the Canadian Neutron Beam Laboratory at the McMaster Nuclear Reactor.

Speaker: Patrick Clancy

223 Quantum PER: A Brief Review

In honour of the International Year of Quantum Science and Technology (IYQ), I will review the physics education research (PER) on learning quantum mechanics, with a focus on introductory courses. This brief overview will include examples of common conceptual difficulties with quantum physics and strategies to guide students to overcome them to generate robust mental models.

Speaker: Carolyn Sealfon (Minerva University)

224 Qubits vs Waves - what works better for introductory quantum mechanics?

Introductory Quantum Mechanics has traditionally been taught in Modern Physics courses, starting with the wave formalism. This approach requires students to learn new physics content, which is quite abstract and sometimes counterintuitive, while applying mathematical techniques most of them have not mastered yet. To avoid this unnecessary complication, we have redesigned our introductory quantum course and start with qubits, two-level systems, using several physical systems for illustration. I will report on the design process, observations and results from the first four years of implementation, and feedback from students in the course, grad students, and faculty members.

Speaker: Daria Ahrensmeier

225 Targeted Crowdsourcing as a PER tool - an Experiment

Physics Education Research (PER) requires data collection from systems that are usually not confined to a lab - humans. A conference is a unique opportunity to question not only individual physicists, but to initiate and observe interactions. In this experiment, we will prepare our systems (the audience) with a brief introduction on known misconceptions in quantum mechanics. Then, we will collect data from individuals about their own experiences with those misconceptions as instructor and/or student. Based on the initial responses, we will assign the participants to specific groups to further explore and refine their responses. Then we will collect the results and discuss next steps.

Speakers: Daria Ahrensmeier, Shania Smagh (Simon Fraser University)

(DPMB) T3-8 | (DPMB): From Code to Communities: Advancing Medical Imaging Through AI and Infrastructure

226 Big Data and Machine Learning in Medical Imaging

Advances in medical imaging have ushered in an era of unprecedented data generation, presenting both opportunities and challenges for modern healthcare. We will explore how big data and machine learning are transforming the field of medical imaging—from accelerating diagnostics to enabling predictive and personalized medicine. Drawing on examples from radiology and multi-modal imaging platforms, the talk will highlight how machine learning algorithms are being trained on vast imaging datasets to detect patterns imperceptible to the human eye. Key topics will include modelling brain aging, handling large image acquisitions, synthetic data generation using generative models, and integrating imaging data with lifestyle and genomic information. Examples will show the image synthesis of amyloid beta positron emission tomography from structural medical imaging using conditional generative adversarial network models and diffusion models for stroke segmentation stroke, and how we use these advanced methods to provide practically useful information. The presentation will also discuss practical considerations, including model interpretability and regulatory pathways for AI-enabled tools. Emphasis will be placed on high-performance computing for data analysis and machine learning.

Speaker: Ethan MacDonald (Biomedical Engineering, University of Calgary)

227 Building Infrastructure for Building MRIs in Remote Communities

In recent years low-field MRI technology has advanced to the point where it is possible to build a complete MRI using parts that total a few tens of thousands of dollars. But to make truly affordable and accessible MRI, a means to make, service and use the MRIs locally in the communities is needed. Local expertise is needed in addition to cheap parts. The first steps in creating that local expertise is education. Since 2023 we have been running student MRI building projects in collaboration with the Saskatchewan Indian Institute of Technologies in Saskatoon. A complete wrist-sized MRI was built by a team of 7 students in the summer of 2024. This summer another student team is making project MRI construction kits for use in community high school physics classes. The kits are based on an MRI designed for the lunar Gateway space station, following the vision of the Canadian Space Agency’s Health Beyond Initiative.

Speaker: Gordon Sarty (University of Saskatchewan)

(PPD) T3-9 Neutrinoless double beta decay and neutrino experiments | Double désintégration beta sans émission de neutrino et expériences sur les neutrinos (PPD)

228 The Canadian search for neutrinoless double beta decay in xenon

Neutrinos are the most abundant know particle with mass in our Universe. Despite their abundance, our knowledge about neutrinos remains incomplete. For example, we do not know any of the masses of the three neutrinos – a unique quantity of fundamental particles! Furthermore, whether neutrinos are Dirac or Majorana fermions remains an unresolved question in particle physics with fundamental implications on the origin of matter and the evolution of our Universe. A promising approach to probe for the Majorana nature of the neutrino is to search for lepton-number violating neutrinoless double decay (0νββ). An observation of this decay would necessarily imply that neutrinos are Majorana particles and prove the existence of physics beyond the Standard Model of particle physics. For this reason, the search for 0νββ has been identified as high priority in national and international strategies.

The nEXO collaboration developed an advanced conceptual design of a detector to search for 0νββ in a single-phase time-projection chamber containing 5 tonnes of liquid xenon enriched to 90% in the ββ-decaying isotope Xe-136. Very recently, the US Department of Energy announced its decision, based on budgetary constraints only, to advance only a competing experiment to construction while continuing the R&D program for nEXO. We see this turn in the US approach as an exciting possibility for Canada to take leadership and realize a flagship xenon-based 0νββ experiment at SNOLAB. To seize on this opportunity, we are designing a strategy to recruit new collaborators across Canada and internationally, and exploring pathways to fund the experiment.

In this talk we will present the status of our efforts to build the Canadian-sited project and we welcome new collaborators to join our exciting quest to unravel the mystery of the neutrino using xenon-detector technology.

Speaker: Thomas Brunner (McGill University)

229 PMT Test Facility for nEXO

A key background in rare-event search experiments is the cosmogenic background. Hosting experiments in deep-underground laboratories can mitigate this background to some extent; however, high-energy muons can still reach these locations. An active muon veto system can tag signals from the passage of muons in the detector and exclude them from the data analysis. The nEXO experiment, expected to be installed at SNOLAB, aims to search for $0\nu\beta\beta$ using a time projection chamber (TPC) filled with 5 tonnes of liquid xenon (LXe), enriched to 90\% in the isotope Xe-136. It features a water-Cherenkov Outer Detector, which serves two important functions. First, it provides passive shielding for the TPC, effectively mitigating low-energy neutrons and gamma rays. Second, it actively detects Cherenkov light, primarily from through-going muons, ensuring that any associated signals are systematically excluded from the final analysis. To detect the Cherenkov light in the outer detector, appropriate instrumentation is required. The Outer Detector will be equipped with 125 photomultiplier tubes (PMTs). The Daya Bay Reactor neutrino experiment has made its PMTs available for use in the nEXO experiment. Before installation, a detailed performance test of these PMTs must be conducted. In this talk, I will discuss the ongoing R\&D work of the PMT test facility at Laurentian University for the nEXO experiment.

Speaker: Teena Vallivilayil John (Postdoctoral Fellow)

230 Development of Photon-to-Digital Converters – A 3D Integrated Digital Single-Photon Detector for Large Scale Photodetection Systems

We have developed 3D integrated Photon-to-Digital Converters (PDC) as an improved alternative to PMTs and SiPMs for photon counting in various radiation applications, particularly for low power consumption in large area systems such as noble liquid dark matter and neutrino searches, or fast neutron spectroscopy.
In previous years we reported on the architecture, the fabrication process, the CMOS readout electronics designed for these applications, and on system integration. Fabrication of the first 3 wafers of PDC was completed at the Teledyne DALSA foundry in Oct. 2024. The SPAD show expected performances with peak sensitivity >50% at 420 nm and dark count rate (DCR) of $0.1~\text{cps}/\mu\text{m}^2$. Within a PDC, the DCR of the 4096 SPADs was characterized, showing 5% to 7% of screamer SPADs with >10$\times$ the average DCR. We will report on the PDC fabrication process, on wafer characterization, on the SPAD performance, and on the operation of the PDC showing low power and timing capability around 100 ps. We will also update on our efforts to produce large tiles of PDCs toward scale integration.

Speaker: Prof. Serge Charlebois (Université de Sherbrooke)

231 Time-of-flight monitoring techniques for the Water Cherenkov Test Experiment

The Hyper-Kamiokande (Hyper-K) project aims to measure neutrino oscillations with unprecedented precision which may answer fundamental questions underlying CP violation in the lepton sector. Minimizing systematic uncertainties is now more important than ever, making prototype experiments such as the Water Cherenkov Test Experiment (WCTE) at CERN essential. WCTE is designed to test photosensor technology and calibration methods that will be used in future water Cherenkov detectors such as the Inner Water Cherenkov Detector (IWCD) and Hyper-K. The physics goals of WCTE include evaluating the electron-muon signal separation capabilities of multi-photomultiplier tubes (mPMTs)—new detector technology primarily developed in Canada—enhancing our understanding of pion scattering kinematics to better constrain the neutrino energy spectrum, and improving electron-gamma separation to reduce background signals. Achieving these measurements requires a precise understanding of the timing information from the mPMTs. We are exploring an alternative technique to obtain time-of-flight-corrected signatures of relativistic, charged particles entering WCTE from the T9 beam. We use Geant4 simulations to evaluate the feasibility of reconstructing the entry time of a particle in the detector based on Cherenkov light detected by the mPMTs. This approach could serve as a valuable cross-check against results from the time-of-flight system, which consists of an upstream and a downstream monitor inside the beam pipe. This presentation will cover the time-of-flight measurement technique and provide an overview of WCTE as we begin data collection in March 2025.

Speaker: Jasmine Jinyin Zhang (TRIUMF (CA))

232 R&D and Status of the LED System for Hyper-K’s LED-mPMT Module

The Hyper-Kamiokande (Hyper-K) far detector is under construction and is planned to begin operation in 2027. The detector will consist of a cylindrical water tank measuring 68 metres in diameter and 72 metres in height, instrumented with 40,000 inward-facing 50-cm photomultiplier tubes (PMTs). To enhance calibration capabilities, 1000 of the conventional PMTs will be replaced by multi-PMT (mPMT) modules: 800 regular mPMTs, each equipped with 19 8-cm fast PMTs, and 200 LED-mPMT modules, each equipped with 14 8-cm fast PMTs and five UV LED light sources pointing in different directions. Each LED system in the LED-mPMT modules includes one diffuser and four collimated UV-light sources at different wavelengths. The combination of these light sources with the fast timing resolution of the mPMTs will allow us to addresses critical calibration aspects for Hyper-K such as (1) calibrating the diffused light source at the opposite wall to improve understanding of the angular response of the 50-cm PMTs and water-attenuation effects, and (2) calibrating the collimated light source to measure water quality in the tank by analyzing light transmission, including position-dependent scattering effects such as those caused by bacteria. In this presentation, I will describe the research and development of the LED system for the LED-mPMT module, its status, and our efforts toward mass production and quality assurance. These efforts ensure readiness for Hyper-K’s start of operation and support its goal of achieving unprecedented precision in neutrino measurements and related physics analyses.

Speaker: Dr Luan Koerich

17:45 Travel Time | Durée du voyage

DAMOPC Poster Session & Student Poster Competition | Session d'affiches DPAMPC et concours d'affiches étudiantes (0)

DAPI Poster Session & Student Poster Competition | Session d'affiches DPAI et concours d'affiches étudiantes (5)

233 (POS-2) Studying Advanced Materials using X-ray Emission Spectroscopy at the REIXS Beamline

Advanced materials, including superconductors, light emitting materials and battery materials, play an ever-increasing role in society today. Studying these materials is key to reducing overall energy consumption for everyday technology. Soft x-rays have the ideal energy for probing the electronic properties of lighter metal and non-metal elements in these materials; x-ray absorption spectroscopy (XAS) and x-ray emission spectroscopy (XES) are robust techniques to measure the electronic structure in general. More advanced techniques, including resonant inelastic x-ray scattering (RIXS), are invaluable for studying electron correlations in novel materials. The Resonant Elastic and Inelastic X-ray Scattering (REIXS) beamline at the Canadian Light Source (CLS) is a soft x-ray beamline specializing in photon-in/photon-out techniques including those mentioned above. There are many opportunities at REIXS for material scientists wanting to study the electronic properties of their advanced materials. We will showcase the current capabilities offered at REIXS with highlights of some case studies.

Speaker: Teak Boyko (Canadian Light Source)

234 (POS-1) Absement Adventures: Mapping Motion in a Relational Universe

This work explores a novel use of absement [L·T] within relational graph theory to model positional kinematics in a relationalistic framework. Unlike traditional vector-based approaches, this method employs rishtar elements—geometric constructs that encode relational distances or durations as object-oriented elements. Here, dimensional time evolution is discrete, universal, and mapped to finite relational distances.
Absement is treated as a mapping between two independent sets, length and time, forming [L·T]. This allows displacement to accumulate over a relational duration, enabling past positions to be identified statically. The model preserves absement’s classical interpretation while integrating discrete changes—such as orbital phases or rotational states—into a geometric structure. To ensure consistency across multiple reference frames, relational graphs incorporate both spatial extensions and temporal durations.
A case study on lunar relational absement illustrates this approach, which models positional relationships without relying on force-based equations. By treating position evolution as a static property within a multi-frame system, this method provides new perspectives for celestial mechanics, time synchronization, and universal reference frame modeling.

Speaker: Dr Steven Moore

235 (POS-5) Effects of Positioning Errors on Ptychographic Imaging

Ptychography is a scanning coherent diffraction imaging technique that reconstructs the two-dimensional complex X-ray transmission function from the far-field diffraction patterns obtained at well known, pre-defined scan points [1,2]. Ptychography played a crucial role in imaging a wide range of technologically important samples ranging from micro-chips to biological cells, spatial resolutions as high as 17 nm were reported [3-7]. Ptychographic imaging depends on three main components: coherent X-ray sources, precise nano-positioning of samples, and efficient phase retrieval algorithms. A systematic investigation of the impact of nano-positioning errors of these scan points on ptychographic reconstructions has not been conducted. We will examine the effects of these errors in two distinct scenarios: (1) when the predefined scan points are missed, but the actual scan point positions are accurately known, and (2) when the predefined scan points are hit accurately, but the recorded positions are erroneous. By analyzing these cases, we aim to enhance our understanding of how positioning errors influence ptychographic reconstructions.

[1] P. Thibault., et al., Science 379:379–383 (2008)
[2] H. M. L. Faulkner and J. M. Rodenburg., Physical Review Letters , 93(2):23901–23903 (2004)
[3] Y. Takahashi., et al., Physical Review B - Condensed Matter and Materials Physics , 83(21):1–5 (2011)
[4] M. Guizar-Sicairos., et al., Optics express , 22(10):14859–14870 (2014)
[5] A. M. Maiden., et al., Nature Communications , 4:1666–1669 (2013)
[6] M. Dierolf., et al., New Journal of Physics , 12:1–14 (2010)
[7] M. Guizar-Sicairos., et al., Optics Express , 19(22):21345–21357 (2011)

Speaker: Nicholas Simonson (University of Saskatchewan)

236 (POS-4) Non-linear Optics Corrections for the Future Circular Collider Electron-Positron Collider Ring

The Future Circular Collider electron-positron machine (FCC-ee) is a proposed successor to the Large Hadron Collider at CERN. The design is for a 91 km accelerator ring to allow particles to be accelerated to extremely high energies, ranging from 45.6 GeV to 182.5 GeV per beam in various operation schemes. Two counter-rotating beams will then be brought into collision at specific interaction points to study the standard model up to a centre of mass energy of \sqrt{s} = 365 GeV.
In order to bring these beams into collision at the interaction points, the particles are steered and focused with a ring of electromagnets. The design of the locations and magnetic fields is called the magnetic lattice, and it constrains the motion of the particles. The range of particle amplitudes and momenta relative to an ideal reference particle that can be stably stored are called the dynamic aperture (DA) and momentum acceptance (MA) respectively.
One of the major limiting factors on the DA and MA are tune resonances which cause unstable beam motion. Tune is the fractional phase advance that a particle undergoes in complete revolution of the ring. An integer tune means that the motion of a particle has the same phase each time it reaches a given location in the ring, so resonant effects of any errors in the machine quickly compound and lead to particle loss. Half-integer tunes mean every second revolution a particle has the same phase, and so on for other rational tunes. A lattice design selects a horizontal and vertical tune that avoids such resonances, but non-linear effects in the machine complicate the issue. Particles with different momenta and oscillation amplitudes are focused differently by the lattice, resulting in momentum and amplitude dependent tune shifts. The shifts can cause particles to move to resonant tunes leading to particle losses and reduced beam lifetime, which is detrimental to experimental quality.
These non-linear effects can be corrected and controlled using higher order magnetic fields which provide opposing non-linear effects to balance the unwanted tune shifts. The work presented here covers initial investigations into the use of high order magnetic fields to correct non-linear tune shifts and enhance the stability of the stored beam in the FCC-ee ring.

Speaker: Patrick Hunchak (University of Saskatchewan (CA))

237 (POS-3) Watching the Watchers: Monitoring the nEXO's Muon Veto System

Large-volume, low-background noble-liquid-based detectors have emerged as a leading technology in neutrino science and dark matter physics. A requirement for these experiments is minimizing environmental radiation, including those caused by neutrons from cosmic radiation. This can be achieved by tagging passing muons, which allows vetoing the data stream and subsequent background events.

nEXO is a neutrinoless double beta ($0\nu\beta\beta$) decay search using a 5-tonne liquid xenon time projection chamber enriched in the isotope xenon-136. With a projected half-life sensitivity of $10^{28}$ years, nEXO requires extremely low background levels. The experiment incorporates a 12.3-meter diameter, 12.8-meter high water tank containing 1.5 kilotonnes of ultra-pure water, equipped with 125 photomultiplier tubes (PMTs).

To maintain the efficiency of muon veto systems, regular monitoring of water quality and the performance of the PMTs is essential. Monitoring of the veto system relies on optical methods, where a controlled light source emits photons, and the response of the PMTs is analyzed to evaluate both their functionality and the quality of the water.

A monitoring system is being developed for the muon veto system of the nEXO experiment. It uses optical fibers to deliver laser light to diffuser balls placed within the tank. I will discuss the conceptual design of the system, its requirements, the simulation results, and the current development status of the prototype.

Speaker: Samin Majidi

DASP Poster Session & Student Poster Competition | Session d'affiches DPAE et concours d'affiches étudiantes (4)

238 (POS-8) Observations of traveling ionospheric disturbances driven by gravity waves generated in extratropical cyclones

Travelling ionospheric disturbances are plasma density fluctuations usually driven by atmospheric gravity waves generated by sources in the upper or lower atmosphere. Eastward to southeastward propagating medium-scale traveling ionospheric disturbances (MSTIDs) are commonly observed at mid latitudes over Europe by the GNSS total electron content (TEC) mapping technique and the multipoint and multifrequency continuous Doppler sounder in Czechia. The MSTIDs appear to be driven by atmospheric gravity waves originating from intensifying extratropical cyclones over the northeast Atlantic. The gravity waves are generated in the low-pressure systems by geostrophic adjustment processes and shear instability. Using the ERA5 meteorological reanalysis the gravity waves are identified in the stratosphere by patterns of alternating bands of convergence and divergence of the horizontal wind, which have been interpreted as a signature of inertia-gravity waves propagating upwards above the tropopause.

Speaker: Paul Prikryl (University of New Brunswick)

239 (POS-6) An Electron Microburst detector for the RADICALS Space Mission

The RADICALS Space mission will consist of a satellite with a suite of detectors designed to study the effects of incoming space radiation on the atmosphere where one of the goals is to measure the flux of precipitating electrons entering the upper atmosphere. This quantitative data will allow better modeling of the physical processes that couple the magnetosphere, ionosphere, and atmosphere, including the creation and destruction of NOx and HOx. An important component of the incident electron flux results from high flux microbursts of electrons generated by wave particle interactions in the magnetosphere. A fast time response electron detector is being designed to measure such microburst events.

This microburst detector will incorporate a scintillator coupled to a silicon photomultiplier (SiPM). The detector is expected to be able to measure electrons with energy of ~200 keV up to ~3 MeV. In order to handle the large variation in particle arrival rates over this large energy band, the detector is split into two heads for the low (<800 keV) and high (>800 keV) energy bands. The detector heads are designed to handle bursts of up to 200,000 counts per second at a measurement cadence of 10 ms and will have geometric factors on the order of 2 cm2 sr and 10 cm2 sr respectively. In order to provide adequate thermal and radiation shielding for the SiPM elements, a light guide will couple the scintillator to the SiPM detector, recessed within the spacecraft structure.

We will present the most recent designs of the detector elements and results of characterization tests conducted using radioisotope and laser-plasma electron sources.

Speaker: Caleb Guthrie

CG CAP_ Space Abstract v2_HT-1.pdf

240 (POS-9) Occurrence of tornado outbreaks in the context of solar wind coupling to magnetosphere-ionosphere-atmosphere

The National Oceanic and Atmospheric Administration National Weather Service database of tornadoes provided by the Storm Prediction Center is used to investigate the occurrence of tornado outbreaks in the United States from 1963 to 2023 in the context of solar wind that impacts the Earth’s magnetosphere. The superposed epoch analysis of daily occurrence of tornadoes reveals a peak in the cumulative number of tornadoes near the interplanetary magnetic field sector boundary (heliospheric current sheet) crossings. Most of the large tornado outbreaks (20 or more tornadoes in 24 hours) are associated with high-density plasma adjacent to the heliospheric current sheet and with co-rotating interaction regions at the leading edge of solar wind high-speed streams. Large tornado outbreaks also followed impacts of interplanetary coronal mass ejections or occurred in the declining phase of major high-speed streams. We consider the role of aurorally generated atmospheric gravity waves in severe weather development leading to tornado outbreaks. While these gravity waves reach the troposphere with attenuated amplitudes, they can contribute to conditional symmetric instability release in frontal zones of extratropical cyclones [1, 2, 3] leading to synoptic-scale weather conditions favouring formation of supercells in the low-level southerly winds and strong wind shear environment. The ERA5 meteorological re-analysis is used to evaluate slantwise convective available potential energy (SCAPE) to assess conditional symmetric instability and slantwise convection in cases of large tornado outbreaks.

[1] Prikryl P., et al., Ann. Geophys., 27, 31–57, 2009.
[2] Prikryl, P., et al., J. Atmos. Sol.-Terr. Phys. 171, 94–110, 2018.
[3] Prikryl, P., Adv. Sci. Res., 21, 1–17, 2024.

Speaker: Paul Prikryl (University of New Brunswick)

DCMMP Poster Session & Student Poster Competition | Session d'affiches DPMCM et concours d'affiches étudiantes (13)

241 (POS-18) A molecular dynamics simulation study of glassy dynamics in supercooled glycerol.

Glycerol is a well-known molecular glass former that appears in several natural and engineered systems and has applications in cryopreservation, amorphous drug formulations, and stabilization of biomolecules. As it is cooled, the viscosity and structural relaxation time, of the liquid rapidly increase until the system falls out of metastable equilibrium and becomes trapped in an amorphous solid state at the glass transition temperature. However, little is known about how the structure of the liquid influences its dynamics. In this work, we use molecular simulation to explore the relationships between structure and dynamics, with a focus on understanding the nature of structural and dynamic heterogeneity in this molecular glass former. The glass transition temperature of the system is determined from the temperature dependence of the density and heat capacity. The dynamics of the system are measured and studied by measuring the diffusion coefficients and neighbour structural relaxation times, while the local dynamics associated with conformational changes are measured in terms of the dihedral angle rotational correlation function. Finally, dynamic heterogeneity is studied using the iso-configurational neighbour relaxation time for individual molecules.

Speaker: Shreya Tiwary (University of Saskatchewan)

242 (POS-10) Extending the Mean First-Passage Time Formalism to the Reconstruction of High Free Energy Barriers

Rare events like crystal nucleation in mildly supercooled liquids occur infrequently but proceed rapidly, resulting in the waiting time for their occurrence being much longer than the timescale of the microscopic dynamics. Activated processes are analyzed through free energy landscapes defined on one or more appropriate reaction coordinates, where transitions between states require overcoming a barrier. In the single reaction coordinate case, the mean first-passage time (MFPT) formalism [J. Wedekind and D. Reguera, J. Phys. Chem. B, 112, 11060 (2008)] enables estimation of transition rates and free energy landscapes using data from unbiased molecular dynamics (MD) simulation, which is useful when the energy barrier is not too high. For a sufficiently large barrier, spontaneous barrier crossings become rare and difficult to observe within feasible simulation times, making the now-conventional MFPT approach impractical. We extend the MFPT-based reconstruction method to overcome the large barrier problem by starting MD trajectories near the transition state. To validate our approach, we apply it to random walk models on a one-dimensional potential energy landscape and compare our results with solutions from transfer matrices and numerical integrals. We further test our method on crystal nucleation in the Lennard-Jones liquid, comparing our results against the umbrella sampling Monte Carlo method.

Speaker: Ying Jiang (Memorial University of Newfoundland)

243 (POS-12) The influence of dynamic/tetrahedral correlations on the ice/water interface

Understanding the mechanisms present behind ice growth in a system of liquid water has posed many challenges, primarily due to the difficulties associated with simulating and quantifying these behaviours microscopically. Here, we make use of previously established molecular dynamics methodologies with the express goal of simulating the steady state growth and melting of ice. The standard TIP4P water model is used to represent the (001) face of cubic ice, and various temperature gradients centered about the melting temperature are applied to ensure proper ice/water coexistence. We investigate the dependency of ice growth and melting on the presence of tetrahedral and dynamic heterogeneities in liquid water. This is done using the isoconfigurational ensemble to identify clusters of tetrahedrally ordered and disordered molecules and clusters of molecules exhibiting fast and slow dynamics. It has been previously observed that crystalline precursor structures in liquid water correlate with regions with regions of slow dynamics and that the presence of dynamic and tetrahedral heterogeneities have a strong effect on the system’s behaviour. Therefore, we seek to explore the role these regions play in ice growth and melting, and how tetrahedrally ordered and disordered clusters of molecules may influence where these regions form.

Speaker: Mathieu Muise (Memorial University)

244 (POS-13) Resonant Soft X-ray Scattering and Reflectometry for Quantum Materials at the REIXS beamline

Resonant soft x-ray scattering (RSXS) has established itself to be one of the most powerful techniques for studying complex electronic ordering phenomena in quantum materials. Different from conventional x-ray scattering, RSXS merges diffraction methods and x-ray absorption spectroscopy, providing not only a unique elemental, site, and valence specificity, but also an enhanced sensitivity to spatial modulations of charge, spin, and orbital degrees of freedom at nanoscopic length scales. With such exceptional capabilities, the interest in exploiting this technique on 3d transition metals and 4f rare earth compounds has been intensified during the recent decades. Prominent examples are incommensurate charge density waves in cuprate superconductors, spin and orbital ordering in colossal magneto-resistive manganite, as well as orbital reconstruction at the interface of oxide heterostructures using resonant x-ray reflectometry (RXR). Here we will highlight a few recent scientific outcomes from the RSXS endstation [1] at the Resonant Elastic and Inelastic X-ray Scattering (REIXS) beamline. In the first case, a new class of material, an infinite-layer nickelate superconductor has spurred much attention in particular after the charge ordering was reported to exist in its parent compounds. By virtue of an energy-resolved Silicon drift detector, the substantial oxygen fluorescence background could be separated out, confirming a clear absence of the charge ordering in the pristine NdNiO$_2$. For the partially reduced NdNiO$_2$, the ordering has instead been linked to the structural modulation consisting of oxygen deficiencies [2]. Next, the RSXS study on the lanthanum-based cuprates under a uniaxial pressure will be shown. Here the asymmetric response of charge ordering parallel versus perpendicular to the applied uniaxial stress is observed despite the lack of significant change of the onset transition temperature of the orderings [3]. Lastly, electronic reconstructions at the complex oxide LaAlO$_3$/SrTiO$_3$ interface have been revisited using RXR. By eliminating the extrinsic factor of oxygen vacancies, the existence of the half charge at a confined reconstructed interface is elucidated. This is fully consistent with the theory of polar catastrophe [4].
[1] D. Hawthorn, et al., Rev. Sci. Instrum. 82, 073104 (2011)
[2] C. Parzyck, et al., Nat. Mater 23, 486 (2024)
[3] N. Gupta, et al., PRB 108, L121113 (2023)
[4] R. Green, et al., Phys. Rev. Mater. 5, 065004 (2021)

Speaker: Ronny Sutarto (Canadian Light Source)

245 (POS-14) Band gap and electronic structure of oxygen-containing Ca5Sb2(NH)2: A soft X-ray spectroscopy and DFT

The air-sensitive Ca5Sb2(NH)2 is studied by soft X-ray absorption spectroscopy (XAS) and emission spectroscopy (XES), which directly probe the partial electronic density of states of the conduction band and valence band, respectively. The density functional theory (DFT) calculations are performed to compare with the measured spectra. The second derivatives of measured N K-edge XES and XAS spectra are used to determine the band gap, which is in good agreement with the calculated band gap using mBJ exchange-correlation potential. The oxygen K-edge XES and XAS spectra are measured to examine the presence of oxygen impurities in the sample. To gain more insight into the structure of Ca5Sb2(NH)2-xOx, DFT calculations are performed for different concentrations of oxygen substitution for nitrogen (4.16, 8.33, and 25%), and it is concluded that the concentration of oxygen impurities lies between 4% and 8% in the sample.

Speaker: Saloni Saloni (University of Saskatchewan)

Abstract_Saloni (CAP 2025).docx

246 (POS-15) Resonant X-ray Reflectometry of a Mn₃Ge-based Quantum Heterostructure

Topological materials offer many interesting quantum phenomena such as anomalous Hall effect (AHE), topological Hall effect (THE), quantum spin liquid state, and skyrmion lattice. Among these materials, Mn3+xGe is one of the interesting quantum materials as it has a triangular spin lattice in the kagome network. Due to this arrangement, collinear antiferromagnetic (AFM) alignment is impossible which creates frustration in the spin system. To minimize energy while stabilizing the frustrations, the Mn spins adopt a 120˚ non-collinear AFM structure instead of collinear AFM. This spin orientation breaks the inversion symmetry locally and produces quantum mechanical effects like AHE, THE, etc. In this work, we systematically studied the electronic, and magnetic properties and exchange coupling between Mn3Ge, and ferromagnetic Fe layered in a quantum heterostructure. For this, depth-resolved elemental and magnetic density profiles were determined through analysis of Resonant X-ray Reflectometry (RXR) data collected at the REIXS beamline of the Canadian Light Source. These structural and magnetic density profiles gave a better visualization of the sample and important information about how magnetization affects the non-collinear AFM Mn3Ge and ferromagnetic Fe in the system and at the interface. This research enhances our understanding of this potential spintronic material and demonstrates RXR to be a powerful technique for studying quantum material heterostructures.

Speaker: Ms Meemansha Bahuguna (Department of Physics and Engineering Physics, University of Saskatchewan, Canada.)

247 (POS-16) Revealing Graphene Oxide Structure using Synchrotron and DFT techniques

Graphene oxide (GO) is the oxidized form of graphene. GO is known for its complex non-stoichiometric structure and unique optical, electronic, and chemical properties which contributes to many applications in electronic devices and is a good precursor for synthesizing reduced graphene at a large scale. Despite being one of the most promising materials, the detailed structure of GO remains unknown, which gives us opportunity to study the material thoroughly. Our study focuses on the local structure and electronic properties of GO. We use synchrotron-based X-ray absorption (XAS) and X-ray emission (XES) spectroscopy, along with density functional theory (DFT), to describe GO structure.

Speaker: Sakshi Sakshi (PhD Student)

Abstract (GO).pdf

248 (POS-17) A Large-Scale Molecular Dynamics Simulation of Compressed Ice

Water, albeit an extremely simple chemical, is the most important for human life and the growth of our society. It is a vital resource for our health, food, and energy production. As the demand for water steadily continues to increase, researchers have begun to dedicate an incredible amount of resources to study it. It should be noted that in order to solve wide-scale and societal problems regarding water, we must also try to understand it on a molecular level. While the structure of liquid water remains elusive, quenched water and disordered ice is an excellent starting point. In this study, a large-scale molecular dynamics simulation of compressed ice 1h has been performed to study the formation of high-density amorphous ice and very high-density amorphous ice. While the mechanism for this phase transition is known, the results of this study provide a much more detailed description of the local structural changes that occur during amorphization. Topological data analysis has been used in tandem with molecular dynamics results to properly characterize the medium-range order of high-density and very high-density amorphous ice.

Speaker: Rielly Castle

CAPS abstract.pdf

249 (POS-19) The effect of quasi-one-dimensional confinement on dynamical heterogeneities in glass forming liquids.

Title: The effect of quasi-one-dimensional confinement on dynamical heterogeneities in glass forming liquids.

Abstract:
Confined fluids display unique characteristics in comparison to bulk fluids. The geometrical constraint of the confining walls introduces incommensurate length scales in particle-particle and particle-wall interactions which lead to fundamental changes in the phase behaviour of glass forming liquids, with either enhancement or suppression of the glass transition [1], Tg, as well as re-entrant crystallization [2] with respect to the degree of confinement. Bulk liquids near the glass transition exhibit dynamical heterogeneities, where local relaxation rates that fluctuate strongly over space and time [3]. Here, we use molecular dynamics to see how confinement to long narrow channels effects dynamical heterogeneities in a 2D binary Kob-Andersen (KA) Lennard-Jones (LJ) mixture as a function of channel diameter. We investigate several dynamic and structural properties including the mean squared displacement, radial distribution function, bond-orientational order parameter and bond-breaking correlation function as the supercooled liquid approaches the glass transition as a function of channel diameter.

[1] T. S. Ingebrigtsen, J. R. Errington, T. M. Truskett, and J. C. Dyre, Predicting How Nanoconfinement Changes the Relaxation Time of a Supercooled Liquid, Phys. Rev. Lett. 111, 235901 (2013).
[2] J. Mittal, T. M. Truskett, J. R. Errington, and G. Hummer, Layering and Position-Dependent Diffusive Dynamics of Confined Fluids, Phys. Rev. Lett. 100, 145901 (2008).
[3] Rajib K. Pandit and Horacio E. Castillo, Simple Model for Dynamic Heterogeneity in Glass-Forming Liquids, Phys. Rev. Lett. 131, 218202 (2023).

Speaker: Josh Gramlich

Gramlich_Josh_Abstract_CAP_2025_v0.pdf

250 (POS-20) Probing the Electronic Structure and Luminescence Mechanisms of BaSiP₃N₇:Eu²⁺ Using DFT and Synchrotron-Based Spectroscopy.

The development of high-efficiency light-emitting diodes (LEDs) relies on advanced luminescent materials that enhance their performance. BaSiP3N7:Eu²⁺ has emerged as a promising phosphor due to its strong luminescence properties. To gain deeper insight into its electronic and optical behavior, we employed a combination of experimental techniques, including X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES), resonant inelastic X-ray scattering (RIXS), and X-ray excited optical luminescence (XEOL), complemented by density functional theory (DFT) calculations.
Our study reveals key electron transition mechanisms, notably the 5d → 4f transition of Eu²⁺, which serves as the primary indicator of luminescence efficiency. Additionally, we examine charge transfer effects, thermal quenching mechanisms, energy transfer pathways, and defect impurities arising from material synthesis in BaSiPN:Eu²⁺, providing deeper insight into the factors that govern its luminescence performance. These findings deepen our understanding of the electronic and optical properties of BaSiP3N7:Eu²⁺, guiding its optimization as a high-performance phosphor for LED applications.

Speaker: Osebi Daudu (university of Saskatchewan)

CAP CONGRESS ABSTRACT.pdf

251 (POS-21) Unraveling \(e_g\) Orbital Splitting in TiO$_2$: The Role of Local Distortion in Ligand Field Multiplet Theory

Transition metals (TM) are d-block elements with partially or completely filled d-orbitals. They display unique and complex behaviors, including variable oxidation states, strong electron correlations, and intricate crystal field effects. Transition metal compounds are technologically and fundamentally important and exhibit a number of interesting effects that can be exploited in applications. Our techniques are ideally suited to studying these effects by probing the electronic structure (for example, crystal field and multiplet effects) in detail.
This presentation provides a comprehensive study of two titanium oxide (TiO$_2$) polymorphs, anatase and rutile. We utilize advanced spectroscopic techniques, including X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS), along with ligand field multiplet theory (LFMT).
Our measurements are compared with theoretical insights. By examining the relationship between $L_3$-edge spiting and the distortion parameters $D_s$ and $D_t$, we show that the splitting of the e$_g$ orbitals is strongly influenced by distortions in local symmetry.

Speaker: Peter Ufondu (University of Saskatchewan)

252 (POS-22) Uncovering the Electronic Environment of a Novel Nitridophosphate: GeP2N4

Characterizing a newly synthesized germanium nitridophosphate, GeP2N4, revealed several interesting aspects of the sample. It is structurally unique to other known MP2N4 systems (M = Be, Ca, Sr, Ba, Mn, Cd) due to the presence of Ge2+ lone pairs that reside within rings of PN4 tetrahedra. Our group makes use of several different techniques to perform these characterizations. Primarily, we perform synchrotron-based X-ray spectroscopy at the REIXS beamline in the Canadian Light Source, probing the electronic states of GeP2N4. More specifically, we find the X-ray emission spectra, X-ray absorption spectra, and X-ray excited optical luminescence. These allow us to determine properties such as the band gap, and make inferences about possible defects, such as vacancies, within our sample. Along with experimental measurements we calculate the entire system using density functional theory in the WIEN2k program. We calculate exactly what we measure, which allows us make direct comparisons between theory and experiment.

Speaker: Cody Somers (University of Saskatchewan)

253 (POS-23) Group Theory and Energies of a Cornerless Two Dimensional Su-Schrieffer-Heeger Model

There exists about three different ways of stacking 1D Su-Schrieffer-Heeger (SSH) chains, and creating an SSH sheet, in such a way that the couplings are alternating in both (x and y) directions, which is the key component of the SSH model. It is known that whereas the original, one dimensional, SSH model had topological edge states, the two dimensional version has edge and corner states. We are interested in what happens when the corners are strongly coupled do leads (semi-infinite, undimerized, chains that model the environment). Such a coupling effectively removes the corners from the system, destroying the corner states. We found that new states, located near the now unexistent corner appear. Those states are isolated in energy and are weakly perturbed by changes to the parameters of the system, suggesting they are topological in nature. The treatment of finite system is particularly challenging, and group theory offers considerable insight, greatly simplifying the system.

Speaker: Ilya Iakoub (Université de Montréal)

254 (POS-11) Calculation of angle-dependent magnetoresistance with magnetic breakdown for temperature dependent anisotropic scattering

Uncovering Fermi surface geometry and scattering mechanisms can lead to important insights into the physics of strongly correlated electron systems. Angle dependent magnetoresistance (ADMR) measurements are a tool to obtain this information that has been used widely in layered metals such as organic charge transfer salts and cuprates. Simple analytic expressions for ADMR based on isotropic Fermi surfaces and isotropic scattering do not capture the full physics of real materials, in which both the Fermi surface and scattering may be anisotropic, scattering may be temperature dependent and there may also be magnetic breakdown. We use a Boltzmann equation framework to calculate expressions for ADMR in the presence of an anisotropic Fermi surface, temperature dependent anisotropic scattering and magnetic breakdown and comment on the applicability of our results to experimental systems.

Speaker: Mrs Sepideh Mirabi (Simon Fraser University)

Abstract.pdf

DGEP Poster Session & Student Poster Competition | Session d'affiches DEGP et concours d'affiches étudiantes (0)

DNP Poster Session & Student Poster Competition | Session d'affiches DPN et concours d'affiches étudiantes (2)

255 (POS-24) From Spin to Structure: Beam Spin Asymmetry and the Strong Force

The KaonLT experiment probes hadron structure by measuring deep exclusive meson production reactions at Jefferson Lab. A set of high momentum, high resolution spectrometers in Hall C allow for precision measurements from which form factors and other observables can be extracted. One possible measurement is the beam spin asymmetry, from which is extracted a polarized interference cross-section ratio $\sigma_{LT’}/\sigma_0$. In this work, $\sigma_{LT’}/\sigma_0$ was extracted from exclusive pion production, and results are compared to previous data and predictions from leading QCD models. This poster will present final results from this analysis, and discuss what the results imply about the structure of the proton.

Speaker: Alicia Postuma (University of Regina)

256 (POS-25) Jets as a probe of dissipative processes in the Quark-Gluon Plasma

Relativistic heavy-ion collisions are reaching temperatures where the quarks and gluons, making up the nuclei, become deconfined and enter a state called the Quark-Gluon plasma (QGP). Its properties are a window into the underlying nature of the strong force at extreme conditions and can be inferred from experimental measurement. During heavy-ion collisions, a collimated spray of energetic particles, known as jets, is formed and will be used to study the QGP. The quarks and gluons (i.e. partons) in the jet, are initially highly excited and will decay through multiple radiations (or splits) into partons of ever-increasing lifetime, while also exchanging energy and momentum with the QGP. As jets have been extensively studied in vacuum (i.e. without a QGP being present), they act as calibrated probes to study how energy-momentum is exchanged with the QGP, thereby providing insight into the properties of the QGP. The QGP medium thus causes jet quenching (energy loss to the medium) and transverse momentum broadening (a broadening of the initially narrow jet cone). A robust theoretical description of the QGP has been achieved through the usage of fluid dynamics. It has been found that the QGP is not an ideal fluid, and its dissipative properties, such as its shear and bulk viscosities, have recently been constrained, using Bayesian analysis relying solely on lower energy (i.e. not jet-related) hadrons. This work aims to include jet observables when constraining QGP viscosity through jet-medium interactions. The nature of these interactions changes as the excitation energy of the partons decrease (or as parton lifetime increases), going from perturbative at high excitation energy to non-perturbative at very low energy scales. Thus, this poster explores how jets are used as a tomographic probe to extract the temperature dependence of QGP viscosities, having access to both its early-time (partonic) and late-time (hadronic) contributions.

Speaker: Lukas Opitz

DPE Poster Session & Student Poster Competition | Session d'affiches DEP et concours d'affiches étudiantes (2)

257 (POS-26) Understanding Chaos in the Double Pendulum: Visualizing KAM Theory and Orbit Dynamics

The double pendulum is renowned for its chaotic behavior, characterized by extreme sensitivity to initial conditions and complex orbit structures. In this study, we explore how changing the arm-length ratio affects the system's dynamics, approximating the Lyapunov exponent and analyzing orbit structures using Poincaré maps. We also investigate the persistence and breakdown of specific regular regions—known as invariant tori—as described by Kolmogorov-Arnold-Moser (KAM) theory.

To visually illustrate these concepts, dynamic simulations of the double pendulum and the corresponding trajectories on the torus are presented. These visualizations clarify the generation of Poincaré maps and effectively demonstrate the principles of KAM theory. KAM theory explains the stability of regular motion regions under small perturbations and predicts their breakdown as disturbances increase. Through a combination of visual aids and analytical insights, this poster elucidates the interplay between regular and chaotic dynamics, highlighting transitions that enhance our understanding of chaos in the double pendulum system.

Speaker: Jaiden Dahlke (Brock University)

258 (POS-27) Exploring cloud dynamics with Cloud Model 1 – insights from a university modeling workshop

We present a two-week educational block course, first conducted at the University of Bonn during the 2023 winter semester, that introduced students to Cloud Model 1 (CM1) and its convection-resolving capabilities. The course provided training in configuring and running CM1 simulations on a high-performance computing cluster, offering participants practical experience in numerical modeling of moist convection. Additionally, an introduction to three-dimensional visualization software enabled the transformation of simulation data into graphical representations, facilitating the interpretation of cloud dynamics. Pre- and post-course surveys indicate its effectiveness in enhancing participants' understanding of the subject matter and showing their steep learning curve. While the first part of the course covers the essentials, participants applied theie acquired knowledge to independent research projects in the second part. Building on this experience, the course is now being adapted to develop learning materials for students at Western University. First experiences and results will be presented here. This course will be used to study severe convective events in Canada together with students.

Speaker: Lisa Schielicke (Western University)

DPMB Poster Session & Student Poster Competition | Session d'affiches DPMB et concours d'affiches étudiantes (7)

259 (POS-28) Evaluation of AirLink Multi-Resonator Array for Animal Imaging: A Preclinical Study

Introduction: The development of high-performance radiofrequency (RF) coil arrays is critical for improving image quality and signal-to-noise ratio (SNR) in preclinical imaging applications. The AirLink Multi-Resonator Array (MRA) has demonstrated promising capabilities in human imaging, and this study aims to evaluate its performance in animal models. The objective is to assess the array’s efficiency in delivering high-resolution imaging while maintaining optimal safety and compatibility with existing MRI systems.
Methods: A set of AirLink MRA coils was adapted for small-animal imaging using a rat on a 1.5T MRI system. The experimental setup included SNR comparison against conventional coils, B1 homogeneity evaluation, and assessment of heating effects during imaging. Phantom studies were conducted to calibrate and optimize the system parameters before in vivo imaging.
Results: Preliminary results indicate that the AirLink MRA provided superior SNR compared to conventional single-loop coils. The array design allowed for improved spatial resolution, enabling detailed anatomical imaging with reduced scan times. B1 mapping confirmed uniform field distribution, and thermal analysis showed no significant heating effects, ensuring safe imaging conditions for live subjects.
Discussion and Conclusion: The AirLink Multi-Resonator Array demonstrated high feasibility for preclinical imaging applications, offering enhanced imaging performance while maintaining safety standards. These findings suggest that the system could be a valuable tool for small-animal MRI research, with potential applications in neuroimaging, oncology, and cardiovascular studies. Future work will focus on further optimization and validation across different animal models and imaging protocols.

Speaker: Ms Yujie Ren (University of Winnipeg)

Evaluation of AirLink Multi-Resonator Array for Animal Imaging.docx

260 (POS-29) Development of a High Power, Fast-Switching Radio Frequency Switch for TRASE MRI

TRansmit Array Spatial Encoding (TRASE) Magnetic Resonance Imaging (MRI) is a method for MRI which uses an array of Radio Frequency (RF) transmission coils that produce RF (B1 ) field phase gradients to spatially encode imaging information. TRASE MRI has allowed progress in the development of low-field, gradient-free MRI designs. These designs are compact MRI designs that could be deployed in remote areas where the resources required to perform imaging with a traditional MRI are not available. Currently, TRASE MRI is limited by the inductive coupling which occurs between the coils in the array during imaging. An RF switch capable of isolating transmit coils during the imaging sequence is required for further progress. The goal of the RF switch development presented here is to keep within the low Size, Weight, and Power (SWaP) profile desired for the next generation of compact MRI designs. Current methods of implementing such an RF switch in MRI -- the use of PIN diodes -- produce too much noise for low field MRI use due to their biasing circuitry. A commercially available RF Integrated Circuit (IC) was found that met the fast-switching and low noise criteria required to function within a TRASE MRI. The RF switch developed was initially simulated using Electronic Automation Design (EDA) software, before being modeled, manufactured, and assembled. The RF switches were integrated with TRASE MRI coils and benchtop experiments were undertaken to investigate efficacy of the switch at decoupling the coils. The results of these experiments will be presented.

Speaker: Micheal Hogue

261 (POS-31) A simulation study of peptides confined in aqueous nanodroplets and nanofilms

We carry out molecular dynamics simulations of peptides confined within aqueous nanodroplets and investigate the influence of the temperature-dependent properties of the nanodroplets on peptide folding, localization within the nanodroplet, and secondary structure. Recent computational studies from our group have revealed the emergence of thermodynamic and structural anomalies in liquid water nanodroplets when cooled significantly below the bulk melting temperature. These anomalies impact the distribution of simple ions within the nanodroplets, and here, we extend this exploration to hydrophobic, amphipathic, and hydrophilic peptides.

Our findings reveal an interplay between density and charge structuring in water nanodroplets and the spatial arrangement of charged and polar residues. We examine the dependence of peptide folding propensity on orientation relative to the nanodroplet surface and the disruption of helical secondary structures as subsurface water structure evolves with temperature. To assess the influence of curvature, we conduct comparative studies using confined water nanofilms, and we also simulate peptides in bulk water for comparison.

We quantify the dynamics of water in our systems with a neighbour correlation function, which indicates how long two molecules remain neighbours. Our results reveal slower dynamics within the droplet interior and faster dynamics closer to the surface below a certain temperature. We report on the effect of the different peptides on the dynamics of water.

Speaker: Ms Yiming Huang (Memorial University of Newfoundland)

262 (POS-30) Central Venous Pressure Optical Sensing in the Internal Jugular Vein: A Case Study

1 Abstract
1.1 Introduction
Venous pressure measurements hold significant clinical importance in intensive
care units, where hemorrhagic shock is a common concern. Traditionally, as-
sessing venous pressure has required catheterization, a risky invasive procedure.
Photoplethysmography (PPG) offers a non-invasive alternative through optical
sensing, where fluctuations in local blood volume modulate the light transmit-
ted through tissue [1]. Developing a robust method to measure Internal Jugular
Vein (IJV) pressure using optical techniques could provide a non-invasive alter-
native to traditional catheterization methods [2].
1.2 Purpose
The purpose of this case study was to use readily available PPG sensors over
the IJV to evaluate the feasibility of measuring central venous pressure. The
Valsalva manoeuvre, a well-known technique for modulating venous pressure,
was employed to determine if a change in signal becomes observable.
1.3 Methods
A cloth PPG sensor was repurposed and placed transversely over the IJV. Red
and infrared channel data were recorded and low-pass filtered to isolate the non-
pulsatile PPG component. Blood pooling in the IJV, indicated by its expansion
and increased light absorption, is hypothesized to produce a drop in the low-
frequency signal.
1.4 Results
The repurposed PPG sensor was able to detect the IJV pulse. The low-passed
output displayed a drop during Valsava.
1
1.5 Discussion
The ability of the repurposed sensor to detect the IJV pulse and pressure change
was demonstrated. Further calibration and application exploration efforts would
advance this research toward clinical applicability. This technology suffers from
motion artifacts, thus requiring mitigating methodologies, technologies, and al-
gorithms.
1.6 Conclusion
This study demonstrated the feasibility of optically sensing the jugular venous
pulse and relative pressure using a common clinical cloth PPG sensor. Future
work will involve a population study to validate these preliminary findings and
assess the broader applicability of this approach.
References
[1] T. Tamura, ”Current progress of photoplethysmography and SPO2 for
health monitoring,” Biomedical Engineering Letters, vol. 9, no. 1, pp. 21–36,
Feb. 2019. DOI: 10.1007/s13534-019-00097-w.
[2] J. F. Hill, J. Campbell, J. G. Chase, and C. G. Pretty, ”Estimation of Ve-
nous Oxygen Saturation Through Non-Invasive Optical Sensing at the Jugu-
lar Veins,” Current Directions in Biomedical Engineering, vol. 10, no. 4, pp.
295-298, 2024. DOI: 10.1515/cdbme-2024-2072.

Speaker: Faraz Sadrzadeh-Afsharazar (Toronto Metropolitan University)

CAP_Abstract.pdf

263 (POS-32) Spatial Angle Filtering (SAF) Imaging Device for Deep Interrogation of Scattering Media

Spatial Angle Filtering (SAF) Imaging Device for Deep Interrogation of Scattering Media

Fiona Zerai, Mina Bagheri, Dr. Aditya Pandya, Dr. Alexandre Douplik
Toronto Metropolitan University

Abstract

Introduction:
Imaging deep tissue structures, such as blood vessels, in scattering media like skin is challenging for optical techniques. This study enhances Spatio-Angular Filtering (SAF), a lens-free fiber optic imaging system, to improve optical imaging depth while maintaining resolution. SAF utilizes a Fiber Optic Plate (FOP), a bundle of micron-sized fibers that minimize resolution loss and improve tissue penetration.

Materials and Methods:
SAF imaging replaces traditional lenses with a FOP, enabling the capture of ballistic light while minimizing scattered light, allowing for high-resolution imaging at greater depths. A spatially resolved diffuse reflectance imaging platform was developed to visualize intrapapillary capillary loops (IPCLs) in skin. The system was optimized using various numerical apertures and near-infrared wavelengths to improve depth and contrast. Skin-mimicking phantoms were fabricated using polydimethylsiloxane (PDMS) incorporated with titanium dioxide and India ink, tuning the optical properties to simulate the dermal and mucosal layers of human skin. The phantoms feature horizontal vascular structures mounted at an angle, allowing for progressively increasing imaging depth as the phantom is scanned.

Results:
Incorporating a low numerical aperture (NA) FOP into the SAF system improved imaging depth, allowing deeper tissue penetration while maintaining resolution. The optimized system, using near-infrared light, enhanced both depth and contrast. The phantoms offer a controlled environment for evaluating the SAF imaging system’s performance. Although imaging with the phantoms is ongoing, their design, which allows for progressively increasing imaging depths up to 6.5mm, ensures that the SAF system’s capabilities for deep tissue penetration are effectively tested.

Conclusion:
This research demonstrates that SAF imaging, combined with biologically relevant phantoms, is a promising method for deep tissue imaging, offering significant potential for applications in early cancer detection, microcirculation imaging, and other medical diagnostics.

Speakers: Dr Alexandre Douplik (Toronto Metropolitan University), Fiona Zerai (Toronto Metropolitan University), Mina Bagheri (Toronto Metropolitan University)

CAP 2025 Abstract (1).pdf

264 (POS-33 Withdrawn) Back projection of image reconstruction

Introduction Positron Emission Tomography (PET) uses radiotracers to visualize the function of the body. The radioactive atom, which is part of the radiotracer, decays through positive beta decay and releases two 511 keV photons in opposite directions. The photons are used to map the location of radiotracers. PET can be used to locate malignant tumours, and for understanding strokes, dementia, among other diseases and disorders. An anatomical imaging method is needed in addition to PET so the functional maps can be overlaid on the anatomy. Traditionally the anatomical imaging method has been CT. More recently MRI has been proposed because it has some advantages over CT as the supplemental method to PET. Aspects of image processing need developing for PET-MR. Preliminary steps in image processing will be shown.
Methods As a first step to understanding the field of image reconstruction, a Matlab program was used which generates CT projections from simulated data and then performs back projection to reconstruct the image. Parameters which were varied during the generation of CT projections include: the angle over which reconstruction is made, and the number of projections. Image matrix size was varied during the back projection.
Results Changes to the basic imaging and reconstruction parameters cause significant changes to the quality of the resulting image. Specifically, image resolution, image contrast, and presence of artifacts vary with image and reconstruction parameters. As expected, simple back projection does not provide high quality images.
Conclusion With the understanding of simple back projection and the role imaging and reconstruction parameters play, study can continue into PET image reconstruction, and more complex reconstruction methods, such as OSEM. This will lead to the start of more complex image reconstruction for PET/MR data with the goal of increasing the use of clinical PET/MRI.
Acknowledgments We acknowledge funding from Heart and Stroke Foundation, Brain Canada, CIHR, and NSERC.
Reference Shrinivas (2025). Reconstruction of Image from Simple Back Projection (https://www.mathworks.com/matlabcentral/fileexchange/42266-reconstruction-of-image-from-simple-back-projection), MATLAB Central File Exchange. Retrieved April 14, 2025.

Speaker: Melissa Anderson

265 (POS-34) Kinetic Approaches to Nucleation

Nucleation is the process by which liquids crystallize during a first order transition. However, despite being an inherently kinetic process, most theoretical approaches focus on the thermodynamics of cluster formation, often using the bulk properties of the perfect crystal as ingredients. Our recent work explores approaches to nucleation that focus on the influence of the monomer addition and loss, and particle ordering kinetics on both the transient and steady state properties of crystal nucleation. In particular, we show that in cases of non-classical crystal nucleation, the interplay between the free energy surface and the microscopic ordering kinetics leads to distinct nucleation pathways where large, disordered clusters, appearing at intermediate times, may play either a direct or indirect role in crystal nucleation.

Speaker: Richard Bowles (University of Saskatchewan)

266 (POS-33) Multi-Directional Myelinated Axon Sizes in a Female Mouse

The brain is composed of various cells, including neurons which transmit electrical signals via axons. These axons, grouped together in fibre tracts, make up the brain’s white matter. Postmortem studies suggest that changes in axon diameter and density within the fibre tracts are associated with disorders such as Alzheimer's disease, schizophrenia, autism spectrum disorders, and more. In vivo measurements of axon diameters could provide an understanding of when and how these changes occur to help determine whether they contribute to disease development. Results obtained from newly developed diffusion magnetic resonance imaging (MRI) can be compared to the gold standard, electron microscopy (EM). MRI overestimates axon diameters possibly due to its unidirectional measurements. Our objective is to measure the distance across myelinated axons in multiple orientations to determine if the direction of MRI measurements affects the estimated size of the axons. Using ImageJ, a 0.77 μm^2 grid, set either horizontally and vertically or at ±45॰ angles, was placed on ten
9.4 μm x 6.6 μm EM images from a female mouse. If a grid line crossed a complete axon, a line was drawn along the grid line and its length recorded to represent the diameter. Currently, data was collected and analyzed for one of the ten images. The weighted mean diameters, weighted by area, were 0.7±0.1 μm, 0.7±0.1 μm,
0.7±0.2 μm, and 0.57±0.05 μm for the horizontal, vertical, +45॰, and -45॰ directions, respectively. Analysis of Variance (ANOVA) demonstrates no significant difference between the various angled diameters for the single slice. Further research must be conducted to determine if the angle of the measurement makes a significant change once all of the data are analyzed. The authors thank Dr. Zou Yue for performing the perfusion fixation, the Vanderbilt Cell Imaging Shared Resource Core for performing the EM, and NSERC and The University of Winnipeg for funding.

Speaker: Jessica de Kort (Physics Department, the University of Winnipeg)

DPP Poster Session & Student Poster Competition | Session d'affiches DPP et concours d'affiches étudiantes (7)

267 (POS-35) Development of a High Intensity Laser Source of MeV Electrons Based on Ponderomotive Acceleration of Electrons

During high powered, short pulse laser interactions with gas targets, electrons are ionized and interact directly with the laser beam. At very high focused intensities of 1018 W cm-2 and higher, the electrons are accelerated to relativistic velocities during each half cycle of acceleration in the focused electric field of the laser. The outward gradient in field intensity, or ponderomotive pressure, accelerates the electrons outwards from the focal volume with energies of the order of the oscillatory energy in the laser field. At very dilute pressures, where collective plasma effects are not important, the exit angle of the electrons is related to the electron energy, with higher energy electrons ejected closer to the forward direction. This phenomenon can be used to generate a relatively sparse relativistic electron source with the ability to control the output energy by selection of angle. Such a source can be useful in many different areas such as calibration of relativistic electron detectors for space missions and by analysing the electron energy spectrum can be used to characterize the peak focal spot intensities which existed in the interaction region. The latter measurement is very important for many ultra-high power (petawatt class) laser facilities around the world.

The generation of such electrons is being studied using the new 15 TW laser facility at the University of Alberta. A multichannel detector based on an array of scintillator-silicon-photomultiplier (SSPM) detectors is being developed to carry out these measurements. The array consists of a 4 x 4 grid of SSPM detectors which can each capture the energy of the electrons at individual grid points with single electron detection capability. In addition, a tunable pulsed electromagnet electron spectrometer is being developed for use in measuring the electron energy distribution at different emission angles.

Experimental results will be presented and compared to expected electron energies based on ponderomotive scattering theory.

Speaker: Caleb Guthrie

Guthrie CAP abstr pm e- RF 250128-1.pdf

268 (POS-37) Comprehensive Modeling of Ion Source Physics

This research project aims to develop numerical models for key physical processes in ion sources, including electron emission from filaments, RF antenna power coupling to the plasma, and Coulomb collisions driving electron thermalization. These models will be implemented using an explicit Particle-In-Cell (PIC) code to simulate plasma behavior and benchmark the results against experimental diagnostics at D-Pace. The project is a four-year collaboration between the University of Victoria and D-Pace, funded by MITACS, with the goal of improving the understanding and optimization of ion source performance.

Speaker: Jasmin Deguire (D-Pace, University of Victoria)

269 (POS-36) Rotational and Electromagnetic Effects on Plasma Acceleration in the Magnetic Nozzle

The flow and acceleration of plasma in a converging-diverging magnetic field has many important applications including nuclear fusion in a magnetic mirror, helicon thrusters for space propulsion and plasma based etching of semiconductors. Electromagnetic effects from an azimuthal magnetic field $B_{\phi}$ and centrifugal effects due to azimuthal plasma rotation $V_{\phi}$ are analyzed for a low $\beta$, cold plasma being accelerated in a magnetic nozzle with a large expansion ratio. By solving the MHD equations in the paraxial approximation with isothermal electrons, the intrinsic coupling of azimuthal rotation and azimuthal magnetic field is studied. It is demonstrated that both rotational and magnetic energy can be converted into translational kinetic energy of ions. It was discovered that azimuthal rotational energy and azimuthal magnetic energy can each be converted into the other, with each type of conversion occurring in either the converging or diverging section of the nozzle. For a sufficiently large expansion ratio the ion flow velocity can exceed the Alfven velocity. Stationary state solutions have been obtained for both transonic and trans-Alfvenic flows. It was found that for a specific set of boundary conditions at the nozzle entrance, a unique solution for plasma flow exists that passes through all 3 critical points where the plasma flow velocity is equal to the phase velocity of the MHD modes corresponding to the slow-magnetosonic, the Alfven and fast-magnetosonic wave.

Speaker: Andy Sabo (University of Saskatchewan)

270 (POS-38) Laser Induced Fluorescence (LIF) investigations of inductively coupled plasma used for plasma immersion ion implantation (PIII)

AUTHOR: M. Jimenez, J. Moreno, R. Golingo, M. Bradley, and L. Couedel.
Affiliation: Physics and Engineering Physics Department, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada.

Plasma Immersion Ion Implantation (PIII) is a widely used technique in materials science and semiconductor manufacturing to modify surface properties through ion implantation. This process involves immersing a target in plasma and applying negative high-voltage pulses (NHVP) to accelerate ions onto the surface of the material. A key aspect of PIII is the dynamics of the plasma sheath expansion during the implantation pulse; this governs the implantation dose rate, as well as other aspects such as surface charge accumulation.

This research focuses on investigating sheath dynamics in a low-temperature inductively coupled plasma ICP-PIII system at the University of Saskatchewan Plasma Physics Lab (USask PPL). Laser-Induced Fluorescence (LIF) diagnostics is employed to spatially resolve the ion velocity distribution function (IVDF) and ion temperature, providing critical insights into plasma-surface interactions. Initial results were obtained using time-integrated LIF spectroscopy, which captured steady-state ion dynamics during the NHVP application. However, to fully characterize the high-voltage sheath evolution throughout the pulse duration, time-resolved LIF measurements are required. Future experiments will focus on advancing time-resolved LIF diagnostics to achieve a more detailed understanding of transient sheath behaviour, which is crucial for optimizing ion implantation efficiency and enhancing surface modification properties.

Speaker: Marilyn Jimenez Jimenez

271 (POS-39) Diamagnetic Dynamo Driven Current Transport In EAST Tokamak

The fluctuation-induced dynamo electric field has been measured in the core of high-temperature EAST tokamak plasmas using Faraday-effect polarimetry and electron cyclotron emission (ECE). The magnetic amplitude of the kink mode (m/n = 1/1) saturates at 30–50 Gauss inside the q = 1 resonant surface. Electron temperature fluctuations reach up to 10% near the resonant surface, where the gradient of electron pressure exhibits a local maximum. These temperature fluctuations are predominantly driven by magnetic perturbations, and a correlation between electron temperature and radial magnetic fluctuations gives rise to a non-vanishing parallel dynamo electric field on the order of 10 mV/m, which is comparable to the resistive electric field (η∥ J). The dynamo electric field is capable of flattening the current profile, thereby facilitating the achievement of "hybrid" modes in a steady-state magnetic equilibrium.

Speaker: Wenzhe Mao (University of Science and Technology of China)

272 (POS-40) The stationary ELM-free H-mode with quasi-coherent mode on EAST

A stationary ELM-free H-mode has been observed on EAST by RF dominant heating with low input torque. This ELM-free H-mode regime always features an edge quasi-coherent mode which seems to be responsible for enhanced particle transport losses. The edge Er plays an important role in the mode excitation, and the mode’s appearance and disappearance are correlated with edge Er.

Speaker: Prof. Chu Zhou (University of Science and Technology of China)

273 (POS-41) Towards Controlled Plasma-Wall Interaction Studies: Pre-Ionization in the USASK 2 kJ DPF

The breakdown, lift-off, and propagation of the initial plasma sheath current (PSC) in Mather-type dense plasma focus (DPF) devices play a critical role in achieving reproducible plasma outflows. These stages influence the initial conditions of the pinch compression phase and affect production of energetic ion beams which can be used for material damage studies. Pre-ionization methods, such as shunt resistors and corona-controlled discharges, have been shown to enhance the reproducibility of plasma outflows, improving the reliability of DPF operation. These methods and their applications are currently under investigation on the USASK DPF 2 kJ device, with the goal of establishing a facility to simulate plasma-wall interaction in fusion reactors. This presentation will provide an overview of these methods, a comparative analysis using the Lee Model, and potential enhancements of USASK DPF discharges. The final objective is to quantify the enhancement of ion flux and fluence that consistent and symmetrical pre-ionization provides for future experimental campaigns.

Speaker: Mr Jeisson Vanegas (PhD candidate)

DQI Poster Session & Student Poster Competition | Session d'affiches DIQ et concours d'affiches étudiantes (1)

274 (POS-42) Measurements of various magnetic field strengths using an NV centers in Diamond

NV$^{-}$ centers have a renowned interest in geophysical sciences due to their unique spin state manipulation in the presence of external stimuli. One of the well-studied effects from the NV center spin state is its change in luminescence intensity when in the presence of a magnetic field. This effect has been used to demonstrate the creation of various types of NV$^{-}$ center magnetometers. Our research demonstrates the different effects NV$^{-}$ center diamond crystal produces in the presence of a magnetic field when optically pumped with a 532 nm laser. We have demonstrated a change in luminescence intensity when in the presence of fields T $ > $ 1 mT without the usage of microwave resonance about 2.87 gHz typically used for nano-Tesla magnetic field detection with NV centers. Comments on the creation and measurement using NV centers are noted. Some experimental details on manipulation of the spin state are other experiments included in this presentation, as well as results on creation of a solid state qubit and other quantum processes that can be created using this qubit.

Speaker: William Davis (University of Saskatchewan)

DTP Poster Session & Student Poster Competition | Session d'affiches DPT et concours d'affiches étudiantes (3)

275 (POS-43) Vertical Beam Size Correction at the Canadian Lightsouce

The Canadian Light Source (CLS) has thirteen insertion devices (IDs), which are strong magnetic arrays with adjustable setpoints used to produce synchrotron radiation from a circulating beam of electrons. Changes in the ID configurations will affect the vertical beam size of the circulating electrons and can consequently reduce the photon flux at the VESPERS beamline. We discuss our preliminary simulations of the theoretical mechanisms underlying the beam size changes and our related experimental measurements. We will then give an overview of our plans to improve the electron beam stability by correcting the vertical beam size.

Speaker: Melissa Ratzlaff (Canadian Lightsouce)

276 (POS-44) Understanding Chaos in the Double Pendulum: Visualizing KAM Theory and Orbit Dynamics

The double pendulum is renowned for its chaotic behavior, characterized by extreme sensitivity to initial conditions and complex orbit structures. In this study, we explore how changing the arm-length ratio affects the system's dynamics, approximating the Lyapunov exponent and analyzing orbit structures using Poincaré maps. We also investigate the persistence and breakdown of specific regular regions—known as invariant tori—as described by Kolmogorov-Arnold-Moser (KAM) theory.

To visually illustrate these concepts, dynamic simulations of the double pendulum and the corresponding trajectories on the torus are presented. These visualizations clarify the generation of Poincaré maps and effectively demonstrate the principles of KAM theory. KAM theory explains the stability of regular motion regions under small perturbations and predicts their breakdown as disturbances increase. Through a combination of visual aids and analytical insights, this poster elucidates the interplay between regular and chaotic dynamics, highlighting transitions that enhance our understanding of chaos in the double pendulum system.

Speaker: Jaiden Dahlke (Brock University)

277 (POS-45) Hydrogenic entanglement as a test for ER = EPR

The ER = EPR conjecture states that entangled particles are connected by microscopic worm holes. We look at some potential consequences of this "worm-hole-mediated entanglement." In particular, we see how they ought to affect the spectra of some well-known quantum systems in physics, such as the Hydrogen atom. Since the effects are significant but not observed experimentally, we are lead to believe that ER might not be EPR. We also suggest some experiments that could possibly be realized in the near future in order to strengthen our conclusion. At the end, we present some of our assumptions (like an electron is a point particle) as likely caveats to our approach.

Speaker: Irfan Javed (University of New Brunswick)

PPD Poster Session & Student Poster Competition | Session d'affiches PPD et concours d'affiches étudiantes (7)

278 (POS-51) Preliminary Data Transfer Integration Tests for ATLAS Liquid Argon Calorimeter Upgrade

The Large Hadron Collider (LHC) at CERN is a powerful particle accelerator designed to push the frontier of particle physics. There are four main detectors along the LHC ring; ATLAS is a cylindrical multipurpose detector with multiple specialized subsystems. At its core, the electromagnetic calorimeter plays a crucial role in measuring the energy of charged particles and photons produced in high energy collisions using liquid argon (LAr) as its active medium, segmented with copper absorbers.

The High-Luminosity (HL) upgrade aims to increase the LHC instantaneous luminosity to nearly 10 times its original design to improve its sensitivity to rare processes and statistically limited measurements. To withstand higher radiation and data rates in the HL-LHC environment, ATLAS is undergoing significant upgrades. The LAr Calorimeter system will feature new front-end and read-out electronics, including improvements in radiation tolerance, new trigger and DAQ (Data Acquisition) systems, revised electronics architecture, and novel read-out technology. At the core of the upgraded read-out electronics are the new Liquid Argon Signal Processing (LASP) boards, responsible for handling all digitized data.

This poster will present preliminary data transfer tests between the future LASP Field Programmable Gate Arrays (FPGAs) and the Global Trigger Board prototype (GCMv3), which manages event selection. This communication is vital for the overall data readout and trigger system. Integration tests between these two systems are performed by evaluating link performance using PRBS31 and Core1990-protocol data structures by conducting bandwidth, latency, jitter, and optical power attenuation measurements. Results demonstrated error-free data transmission over 12+ hours, confirmed theoretical bandwidth predictions, and showed latency values consistent with expectations based on the implemented firmware logic. Additionally, attenuation tests indicated significant bit errors emerging at 6 dB. These findings contribute to optimizing high-speed data links between the primary data processing and trigger boards, both essential for informing the final design of the LAr calorimeter readout scheme for HL-LHC.

Speaker: Laura Gonzalez Escudero (McGill University, (CA))

279 (POS-46) Measuring Temperature dependent Drift Times for the HELIX experiment

HELIX (High Energy Light Isotope eXperiment) is a ballon experiment designed to measure abundance of cosmic ray isotopes from hydrogen to neon, with a particular interest in abundances of beryllium isotopes. HELIX aims to provide essential data to study the cosmic ray propagation in our galaxy. The Drift Chamber Tracker (DCT) in HELIX is a multi-wire gas drift chamber designed to measure the position of incident cosmic rays. It is located inside a magnet, bending the trajectory of incoming particles through 72-layers of tracking, enabling the measurement of the momentum of incoming particles.
Before the data can be used for scientific analysis the instrument must be well calibrated. In order to calibrate the DCT data it was necessary to determine the maximum drift velocity of each wire over a short period of time. To do this I developed an algorithm to be able to identify the maximum drift velocity for each wire over each dataset. This revealed a position dependence of the data within the detector. I preformed a study on the temperature dependence of the drift velocities analyzing data from different time periods over the course of the flight, to characterize this dependence I also built a predicted heat map of the gas within the detector over the course of the flight. This involved calibrating the thermistors based on data collected when the experiment was on the ground. This helped confirm that the predicted temperature was reasonable and that the variation was temperature dependent. This algorithms and this study can now be applied to the full data set to develop a calibration method.

Speaker: Gabrielle Barsky-Giles

280 (POS-47) SPEARS – A Scalable Library for Spectral Line Retrieval in DESI-EDR

Context: For numerous application within astrophysics and cosmology, it is of paramount importance to be able to access the present spectral lines from extra galactic spectra in a iterable and efficient manner.
Aims: The SPEARS library (Sparcl Pipeline for Emission-Absorption line Retrieval and Spectroscopy) aims to provide researchers with an easily-accessible and scalable method to determine spectral line presence across a the large database of extra galactic spectra in the DESI-EDR.
Methods: The SPEARS library is publicly available through PyPi, and is installable through pip. The module is importable into python, and contains several functions which follow the process of spectral analysis and which concatenate sub-functions into a streamlined method.
Results: The SPEARS library provides an efficient method to complete iterable spectral analysis across all 1,125,635 unique extra galactic spectra obtained through the DESI-EDR available through the SPARCL API. Providing researchers with the ability for spectral normalization, spectral line analysis, and various other figures such as line-deviation and flux at line wavelengths.

Speaker: Justin Domagala-Tang (Western Univeristy)

281 (POS-48) Improving the efficiency of SuperCDMS background simulations with Geant4's Importance Biasing

SuperCDMS is a direct detection dark matter (DM) experiment which is currently being built at the SNOLAB underground laboratory in Sudbury, Canada. It will operate cryogenically cooled Ge and Si crystals with different sensor designs to perform a broadband DM search for particles with masses $\le 10\, \text{GeV}/c^2$, thus exploring new regions of interest.

Among the key requirements to reach this sensitivity are 1) to provide a sufficiently low background environment, and 2) to understand the background composition of the measured energy spectra. The former is achieved by several layers of lead and hydrogen-rich materials to shield the detectors from external radiation. For the latter, Geant4 simulations are performed taking into account the measured radioactive impurities from screening materials. As the shielding is designed to be very effective, the simulations that propagate particles through the thick shielding lack in statistics in terms of number of detector hits, which leads to large uncertainties in the background composition.

Geant4 provides a mechanism called Importance Biasing which can significantly increase the number of particles that travel into the direction of the sensitive detectors.
Effectively, Importance Biasing has the potential to increase the number of detectors hits by orders of magnitude while at the same time consuming less CPU time on a per-event basis.

This talk will discuss the working principle of Importance Biasing and its implementation in the SuperCDMS simulation framework, explain how to distinguish different event topologies to reconstruct the simulated energy spectra and show the achieved efficiency boost in the respective background simulations.

Speaker: Birgit Zatschler (Laurentian University, SNOLAB, University of Toronto)

282 (POS-50) Molecular Dynamics Simulation of Bubble Formation in Liquid Scintillators

Bubble chambers have been used in the search for dark matter in the form of Weakly Interacting Massive Particles (WIMPs), as well as in the search for neutrinoless double beta decay. The Scintillating Bubble Chamber (SBC) is one such detector which uses an active volume of xenon-doped liquid argon (LAr), a scintillator which allows for the rejection of different classes of background events. In this study, a custom molecular dynamics simulation was written using HOOMD-blue to study the effects of energy deposited through scintillation on bubble formation thresholds in the detector. The simulation uses the parameterized Lennard-Jones potential to model intermolecular forces, common in other molecular dynamics simulations using software like LAMMPS. However, it modifies the standard Seitz “heat spike” model of bubble formation to permit more detailed modeling of atomic recoils and introduce a time-delayed release of energy as scintillation occurs. Preliminary results suggest that most scintillation energy is released on too slow a time scale to be consequential to bubble nucleation. Additionally, bubbles formed using this modified heat spike seem to exhibit the distinct “stages” of proto-bubble formation and rapid expansion before settling into stable growth or contraction, consistent with what has been observed in other molecular dynamics simulations.

Speaker: Jack Walker (Queen's University)

Collab Talk.pptx

283 (POS-49) Detection of Cosmic Ray Muons with Teachspin and Cosmic Watch Muon Detectors

Muons, fundamental particles within the Standard Model of Particle Physics, are produced as a result of cosmic rays colliding with the Earth's upper atmosphere. They only exist for 2.2 microseconds before they decay into other fundamental particles. However, they are moving at velocities near the speed of light, allowing them to reach the Earth’s surface. Muons can be detected using scintillator-based detectors, which use photomultipliers to distinguish muons from other particles. The goal of this research is to investigate the muon flux in the Antigonish area, focusing on how altitude affects the flux. This data can be used to calculate other muon properties, like lifetime and energy.
Two different muon detectors were used for this experiment. The first of these is the Teachspin Muon Detector, which utilizes a photomultiplier tube to amplify signals generated by muons interacting with the scintillator. This detector was calibrated based on the well-established value for muon lifetime. The second detector, the Cosmic Watch Muon Detector, was constructed by the research student following the guidelines of MIT’s Cosmic Watch outreach program, which guides students in building their own muon detectors. This inexpensive, portable detector excels at distinguishing muons from other particles, making it particularly well-suited for flux-related experiments.
This presentation will provide a theoretical background on muons, followed by an explanation of the detection process, including the design and operation of both detectors. The data collection process will be outlined, along with an analysis and presentation of the experimental results. Through this investigation, the goal is to contribute to a deeper understanding of muon behavior in this region.

Speaker: Maxwell MacNeil (St. Francis Xavier University)

19:45 CJP Editorial Board Dinner

19:45 Departmental Leaders Meeting (by invitation only) / Réunion des directeurs(directrices) de département (sur invitation seulement)

19:45 Open Forum with Student Advisory Council followed by possible student networking event

Wednesday 11 June

07:30 Congress Registration and Information (07h30-17h00) | Inscription au congrès et information (07h30-17h00)

08:45 Plenary hall opens | Ouverture de la salle plénière

W-PLEN1 NSERC Community Update Session | Session plénière

09:45 Health Break with Exhibitors | Pause santé avec les exposants

(DGEP) W1-1 Wikipedia Edit-a-thon | Edit-a-thon Wikipédia (DEGP): Celebrating Canadian Women and Gender Minorities in Physics | Célébration des femmes canadiennes et des minorités de genre dans le domaine de la physique

Wikipedia Women in Physics Edit-A-Thon Slides - redux.pdf

Wikipedia Women in Physics Edit-A-Thon Slides - redux.pptx

(DQI/DPE/DPSR) W1-10 Q-STATE: Quantum Science, Technology, Applications, Training, and Education | Q-STATE : Science, technologie, applications, formation et éducation quantiques (DIQ/DEP/DPSR)

Open Source Quantum Information and Ethical Quantum Innovation

284 Workshop with Benjamin MacLellan

285 Panel Discussion: Open Source Quantum Information and Ethical Quantum Innovation

(DPMB/DCMMP) W1-11 Soft Condensed Matter and Biological Physics | Matière condensée molle et physique biologique (DPMB/DPMCM)

286 Building better biomolecular physics models with differentiable simulation

Developing physics-based models for molecular simulation requires fitting many unknown parameters to experimental datasets of diverse properties. Model development typically proceeds according to the trial-and-error tinkering of individual researchers, and the procedures by which parameters are chosen are often opaque and irreproducible. This erects significant barriers to extending and improving existing models – for example, refitting parameters to new experimental data – leading to redundant models of nucleic acids and protein, as developing a new model from scratch is often easier than tweaking extant models. In this talk, I’ll highlight how my collaborators and I are leveraging machine learning tools – namely, gradient estimates with automatic differentiation – to facilitate the extensible, reproducible, and transparent fitting of the physics-based DNA model oxDNA. We have developed a differentiable nucleic acid model: jaxDNA, which I’ll use to illustrate simultaneous parameter fitting to multiple loss functions, spanning structural, mechanical, and thermodynamic data. Our framework can also be used to ‘reverse engineer’ DNA systems, and I’ll show results for inverse DNA sequence design. Finally, I’ll demonstrate how our open-source jaxDNA framework can be used to customize models and objective functions. Though grounded in oxDNA, our work provides a general framework for extensible, community-driven force field development we hope will lead to improved models for systems ranging from RNA to proteins.

Speaker: Megan Engel (University of Calgary)

287 Bridging nano- and mesoscale nuclear organization with correlative single molecule lattice light sheet microscopy

In the nucleus, essential biological processes rely on proteins diffusing through and interacting with a complex network of nucleic acid polymers. To better understand this dynamic interplay requires an advanced imaging platform that simultaneously tracks single-molecule dynamics and the local chromatin environment in live cells. In this talk, I will present our work that combines super-resolution imaging, novel fluorescent probes, and biophysical modeling and reveal that as chromatin density increases, nucleosomes exhibit distinct diffusion and packing behaviors, while the viscoelasticity and accessibility of the interchromatin space remain unchanged. Disrupting nuclear functions alters nucleosome dynamics in a manner dependent on both local chromatin density and relative location within the nucleus. Our findings support a model in which transcription stabilizes nucleosomes locally while facilitating the free exchange of nuclear proteins. Furthermore, we show that nuclear heterogeneity arises from both active and passive mechanisms, underscoring the importance of considering diverse organizational principles when modeling different chromatin environments.

Speaker: Yu Shi (Western University, Physics and Astronomy)

288 A molecular dynamics study of peptides confined in aqueous nanodroplets and nanofilms

We carry out molecular dynamics simulations of peptides confined within aqueous nanodroplets and investigate the influence of the temperature-dependent properties of the nanodroplets on peptide folding, localization within the nanodroplet, and secondary structure. Recent computational studies from our group have revealed the emergence of thermodynamic and structural anomalies in liquid water nanodroplets when cooled significantly below the bulk melting temperature. These anomalies impact the distribution of simple ions within the nanodroplets, and here, we extend this exploration to hydrophobic, amphipathic, and hydrophilic peptides.

Our findings reveal an interplay between density and charge structuring in water nanodroplets and the spatial arrangement of charged and polar residues. We examine the dependence of peptide folding propensity on orientation relative to the nanodroplet surface and the disruption of helical secondary structures as subsurface water structure evolves with temperature. To assess the influence of curvature, we conduct comparative studies using confined water nanofilms, and we also simulate peptides in bulk water for comparison.

We quantify the dynamics of water in our systems with a neighbour correlation function, which indicates how long two molecules remain neighbours. Our results reveal slower dynamics within the droplet interior and faster dynamics closer to the surface below a certain temperature. We report on the effect of the different peptides on the dynamics of water.

Speaker: Yiming Huang (Memorial University of Newfoundland)

289 The dynamics of particles with ligand-receptor contacts

One way to glue objects together at the nanoscale or microscale is by ligand-receptor interactions, where short sticky hair-like ligands stick to receptors on another surface, much like velcro on the nanoscale. Such interactions are common in biological systems, such as white blood cells, virus particles, cargo in the nuclear pore complex, etc, and they are also useful in materials science, where coating colloids with single-stranded DNA creates particles with programmable interactions. In these systems, the ligand-receptor interactions not only hold particles together, but also influence their dynamics. How do such particles move? Do they “roll” on each others’ surfaces, as is commonly thought? Or could they slide? And does it matter? In this talk I will introduce our modelling and experimental efforts aimed at understanding the coarse-grained dynamics of particles with ligand-receptor interactions. Our models predict these interactions can change the particles' effective diffusion by orders of magnitude. Our experiments, using DNA-coated colloids, verify this dramatic dynamical slowdown, but also show other dynamical features not yet captured by our models, which suggest new avenues for exploration.

Speaker: Miranda Holmes-Cerfon (UBC, Department of Mathematics)

(DASP) W1-2 Space Weather Special Session | Session spéciale sur la météorologie spatiale (DPAE)

Conveners: David Themens (University of New Brunswick), Hannah Parry (University of Alberta)

290 The high latitude ionospheric response to the major May 2024 geomagnetic storm

The high latitude ionospheric evolution of the May 10-11, 2024, geomagnetic storm is investigated in terms of Total Electron Content (TEC) and contextualized with Incoherent Scatter Radar and ionosonde observations. Substantial plasma lifting is observed within the initial Storm Enhanced Density (SED) plume with ionospheric peak heights increasing by 150km to 300km periodically until sunset, reaching levels of up to 630km. Scintillation is observed within the cusp during the initial expansion phase of the storm, spreading across the auroral oval thereafter. Patch transport into the polar cap produces broad regions of scintillation that are rapidly cleared from the region after a strong Interplanetary Magnetic Field reversal at 2230UT. Strong heating and composition changes result in the complete absence of the F2-layer (G-Condition) on the 11th, suffocating high latitude convection from dense plasma necessary for Tongue of Ionization and patch formation, ultimately resulting in a suppression of polar cap scintillation on the 11th. The F2-region remains absent in the morning sector within the polar cap and auroral oval regions until May 14th.

Speaker: David Themens (University of New Brunswick)

291 The Fast Borealis Ionosphere: New observations and insights from mapping the polar ionosphere every four seconds

For the past three decades, ionospheric drift velocity measurements from the Super Dual Auroral Radar Network (SuperDARN) have been combined at a nominal time resolution of two minutes to produce horizontal patterns of the high-latitude convective flow. Recently, SuperDARN radars operated by the University of Saskatchewan (codenamed Borealis), which overlook much of the northern hemisphere polar cap, have been upgraded to enable a form of scanning which can be carried out every 3.7 seconds without compromising on the large field-of-views of the radars. When data from all Borealis radars are combined, a 32-fold temporal resolution improvement over traditional SuperDARN convection maps is achieved. We call this new data product the Fast Borealis Ionosphere (FBI).

The SuperDARN FBI allows for the study of highly transient and quickly evolving ionospheric phenomena (on the order of seconds) that span several thousands of kilometres, such as transient flow bursts, polar cap patches, substorm-related enhancements, and more. In this presentation, we show FBI results for events highlighting its capabilities in capturing transient ionospheric dynamics, along with several conjunction studies with satellites and other ground-based instruments (such as all-sky cameras).

Speaker: Daniel Billett (University of Saskatchewan)

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292 Geomagnetically induced currents in Alberta, Canada during the May 10-12, 2024 Gannon storm

Severe geomagnetic disturbances (GMDs) caused by intense solar storms can induce geomagnetically induced currents (GICs) in the Earth and within long conductive infrastructure, possibly posing significant risks to electricity transmission systems. Though no outages or damages were documented, transformer neutral-to-ground current measurements, provided by AltaLink L.P., recorded GICs exceeding 150 A through three transformer neutrals during the geomagnetic storm on May 10-13th, 2024. We investigate the solar wind conditions and magnetospheric processes responsible for the two most significant GIC events observed in Alberta during the storm, focusing on the period from 08:00 to 11:00 UT on May 11, 2024. The first GIC event, around 8:50 UT, reached a maximum amplitude of ~20 A measured on the transformer neutral at a substation in southern Alberta and was driven by substorm-related activity with an onset at mid latitudes. The second GIC event at approximately 9:40 UT resulted from magnetospheric compression triggered by a rapid increase in solar wind density, leading to a stronger global response and a peak GIC amplitude of ~165 A in central Alberta. A high-fidelity DC-equivalent network model, data-driven by the observed GMD, estimated a maximum GIC of approximately 150 A at a transformer substation in central Alberta west of Edmonton around 9:40 UT with the total peak lasting ~12 minutes. The correlation between observed GICs and those from the model was 0.84. Additionally, GIC estimates derived from the differential magnetometer measurement technique indicated a short-lived peak of ~100 A in central Alberta at 11:00 UT, which was not captured in transformer neutral-to-ground measurements. This difference between GIC measured on the transformer neutral and in the power line is presumably due to the slower inertial timescale of induced currents in the network and highlights the complexity of the power network itself. Here, observations along the space weather chain highlight key storm features of varying temporal and spatial scales relevant to GICs during the May 2024 geomagnetic storm. Further, the complexity of the electric power grid response is underscored by comparison of GIC on different network elements.

Speaker: Hannah Parry (University of Alberta)

293 Progress towards a polar-cap patch detection algorithm using SuperDARN data

A polar cap patch is defined operationally as an enhancement in plasma density within the high-latitude F-region of the ionosphere, having spatial scale of the order of 100 km and featuring a density that exceeds twice that of the surrounding ionosphere. The occurrence of patches at high latitudes is important for two main reasons. First, they arise from complex interactions in the magnetosphere-ionosphere-thermosphere (M-I-T) system. Second, patches are suspected to act as a strong High Frequency (HF; 3 - 30 MHz) scintillation source in the high-latitude ionosphere. This scintillation appears in the form of ionospheric backscatter due to field-aligned-irregularities seeded by the patch, and also deviations from great-circle path trajectories due to the strong horizontal plasma density gradients inherent to patches. Despite the clear need to monitor polar cap patches actively, an automated method for detecting them using HF instruments has not yet been developed. In this study, we present the progress made towards understanding the patches' signature within HF backscatter signal obtained by the Super Dual Auroral Radar Network (SuperDARN), a radar system that provides real-time observations across northern and southern high- and mid-latitudes.

Speaker: Gareth Perry (New Jersey Institute of Technology)

294 The new capabilities of the SuperDARN Canada Borealis Radar System

The SuperDARN Canada team will be releasing the first full version of the Borealis digital radar system software this year. This presentation will outline the newly developed advanced capabilities of the Borealis system and the new experimental modes now available to the SuperDARN Canada radars.

Speaker: Draven Galeschuk (University of Saskatchewan)

295 Space Weather Ionospheric Network Canada

Space Weather Ionospheric Network Canada (SWINCan), formerly the Canadian High Arctic Ionospheric Network (CHAIN), has provided continuous, near-real-time monitoring of the high-latitude ionosphere since 2007. SWINCan is operated by the Radio and Space Physics Laboratory (RSPL) at the University of New Brunswick (UNB). The network currently consists of 10 high-frequency (HF) ionosondes, 30 Global Navigation Satellite System (GNSS) total electron content and scintillation monitors (GISTMs), and 14 “low-cost” GNSS receivers spanning northern sub-auroral, auroral, and polar regions. SWINCan also includes 1 GISTM in sub-auroral Antarctica for interhemispheric and collaborative southern ionosphere studies.

There is growing demand for enhanced capacity to observe the high-latitude ionosphere, largely motivated by renewed urgency for increased Arctic domain awareness in support of governance, security, development, and scientific research among Arctic nations. In response, RSPL is substantially expanding SWINCan to include a total of 131 GISTMs and 21 ionosonde systems across Canada, while modernizing its ionosonde network with deployment of “sanimut”, a state-of-the-art, fully versatile HF platform. The complete SWINCan network will provide continuous, near-real-time (NRT) monitoring of the multi-scale ionospheric structure and dynamics at high-latitudes with unprecedented detail and revolutionize our ability to fundamentally understand the physical mechanisms that drive ionospheric variability and influence the trans-ionospheric propagation of radio waves. Given the continuous and unpredictable structuring of the high-latitude ionosphere over a broad range of spatial scales, SWINCan observations provide essential input for ionosphere assimilations models and other adaptive operational strategies of over-the-horizon-radar (OTHR), radio communication systems, and position, navigation, and timing (PNT) systems.

Speaker: Christopher Watson (University of New Brunswick)

296 Statistical assessment of the risk of ionospheric absorption to high frequency communications at high latitudes

Ionospheric absorption degrades high frequency radio wave propagation following solar events that enhance either photoionization or energetic particle precipitation. The high-latitude region poleward of 50° magnetic latitude is particularly vulnerable because of the frequency and widespread effects of auroral and polar cap absorption events. Shortwave fadeout, auroral absorption and polar cap absorption were independently modelled at 30 MHz in 5-minute increments between 1986 and 2017. The combined total absorption was evaluated to determine the overall and yearly probability of exceeding 0.5 dB, 1.0 dB, and 2.0 dB thresholds. At the 1.0 dB threshold the highest probability (>1%) is observed in an oval poleward of ~60° magnetic latitude coincident with the low-latitude cut-off for polar cap absorption. Enhancements of > 2% are observed along an oval-shaped ring centered at 65° magnetic latitude, which is the latitude of maximum enhancement for auroral absorption. Shortwave fadeout contributes minimally to the probability distribution with an occurrence of < 0.03% and peak values near the most equatorward portions of the high-latitude region. Yearly probability statistics are reflective of the solar cycle with values ranging from near 0% in 2009 to >10% in 1991 and nearly 30% in 1989.

Speaker: Robyn Fiori (Natural Resources Canada)

(DAMOPC) W1-3 Current Trends/Hot Topics | Tendances actuelles/sujets d'actualité (DPAMPC)

(PPD) W1-4 Flavour Physics & Beyond | La physique des saveurs et au-delà (PPD)

297 Flavor and the Baryon Asymmetry of the Universe

The baryon asymmetry of the universe cannot be explained with the Standard Model. Furthermore, the SM also does not address why fermion masses are highly hierarchical. I will discuss a "flavon" model, which addresses both of these problems. I will also discuss collider and cosmological signals of such a flavor/baryogenesis model.

Speaker: Seyda Ipek

298 Recent results and future prospects with the Belle II experiment

The Belle II experiment at the KEK laboratory has collected data at energies at and near the $\Upsilon(4S)$ resonance since 2019, with active Canadian participation in this project since 2013. The Belle II physics program spans a broad range of physics topics, including both heavy quark and lepton flavour, performing precision measurements of flavour observables, as well as high sensitivity searches for rare and exotic decay processes. This talk will provide an overview of the physics program, highlighting recent interesting results in flavour and exotic new-physics searches.

Speaker: Steven Robertson (IPP / University of Alberta)

299 Recent results from the LHCb experiment

The LHCb experiment at CERN is a single-arm forward spectrometer designed to study the production and decay of beauty and charm hadrons produced in Large Hadron Collider collisions. This talk will review some highlights of recent measurements by the LHCb collaboration. The experiment has recently undergone a major upgrade for Run 3 and Run 4 of LHC. This upgrade, and plans for a further upgrade for the high-luminosity phase of the LHC, will also be discussed.

Speaker: Thomas Blake (University of Victoria)

300 Probing New Physics: The Role of Vector-Like Quarks in Rare B-Decays

We investigate the impact of Vector-Like Quarks (VLQs) on rare B-decay processes. Our approach involves careful examination of VLQ contributions in light of the most recent lower mass limit set by direct search data at LHC. By employing both symbolic and numerical computations, we compare our theoretical produce predictions in agreement with the latest Belle-II results, covering more than 3 sigma deviation from SM expectations. This study aims to shed light on underlying mechanisms that could signal a possible new physics beyond the Standard Model scenario and offer valuable insights for future experimental searches.

Speaker: Maryam Bibi (Memorial University of Newfoundland)

(DTP) W1-5 Hot Topics in Theoretical Physics | Sujets d'actualité en physique théorique (DPT): Black Holes, Gravitational Waves and Neutron Stars | Trous noirs, ondes gravitationnelles et étoiles à neutrons

301 Gravitational Self-Lensing of X-rays Emitted by Neutron Stars

Neutron stars are the densest known gravitationally-stable objects in the Universe. Their strong gravitational fields, rapid rotation rates, and supra-nuclear central densities allow for a fascinating interplay between general relativistic effects and nuclear physics theory. Pulse-profile modeling is a technique that uses the gravitationally-lensed X-ray flux emitted from hot spots on the neutron star's surface to infer its mass and radius. General relativity is a crucial ingredient in this analysis. The Neutron Star Interior Composition ExploreR (NICER) is a NASA X-ray telescope mounted on the International Space Station. NICER is a timing instrument designed to make the measurements required to implement pulse-profile modelling. In this talk, I will give an overview of how NICER data is used to infer a neutron star's radius (and its mass), along with the latest results and future observations of other pulsars.

Speaker: Sharon Morsink (University of Alberta)

302 New Frontiers in Black Hole Astrophysics

From the smallest particles to the largest structures in the Universe, physics seeks to understand how matter interacts. At the heart of some of the most energetic environments in the cosmos, supermassive black holes shape galaxies across cosmic time through powerful jets and outflows—a process known as black hole feedback—which regulates the growth of galaxies and even entire galaxy clusters.

In this talk, I will explore how black hole feedback drives cosmic evolution and how new observations are transforming our understanding of this process. I will highlight the first results from XRISM, a next-generation X-ray space telescope providing unprecedented insights into hot gas motions in galaxy clusters, and discuss how machine learning is revolutionizing our ability to study black hole feedback in the decades to come.

Speaker: Julie Hlavacek-Larrondo (Université de Montréal)

303 Multi-messenger modeling of isolated neutron star binary mergers in the era of third generation gravitational-wave detectors

Multi-messenger astronomy was revolutionized by the detections of gravitational waves (GW) from the binary neutron star (BNS) merger GW170817 and electromagnetic (EM) waves from the resultant kilonova explosion and short gamma ray burst. This single event confirmed the association of the latter two EM signals with BNS mergers, and the possibility of a kilonova remnant, analogous to a supernova remnant, has motivated studies of the late-stage evolution of the system. Together, these processes and phenomena form a multi-messenger nexus which places independent but astrophysically relatable constraints on the progenitors and products of BNS mergers. Simultaneously, GW170817 helped initiate new observational and theoretical strategies in anticipation of future GW and EM detectors, whose unprecedented sensitivities will illuminate the uncertain physics of BNS mergers and their progenitors. This implies a great demand for the development of comprehensive modeling frameworks that account for multiple scales and processes relevant for many multi-messenger observables. We demonstrate how combining currently available models of different aspects of the BNS progenitor-merger-product system reveals insights and modeling challenges that will need to be addressed in the coming decade of multi-messenger astronomy. Motivated by GW170817, this combined model relates the progenitor astrophysics of a BNS population with their (i) GW observability and localizability, (ii) kilonovae and GRB afterglows, and (iii) kilonovae remnants. We find that a network composed of at least three 40km gravitational wave detectors will be needed for optimal multi-messenger constraints; and that joint correlations between the GW and EM observables depend on a complicated interplay between modeling assumptions. We conclude with discussion on key astrophysical modeling systematics that will be crucial in the analysis of future datasets.

Speaker: Dr Nathan Steinle (University of Manitoba)

304 The interface of theory and observation in gravitational waves

Gravitational waves, first predicted by Einstein's theory of general relativity, have opened a new window for observing the universe. Detections of coalescing binaries made by gravitational-wave observatories rely on both accurate theoretical models and precise observational techniques, bridging theory and data together. This talk will review how theory has helped bring us into the era of gravitational wave astronomy, and how it will continue to advance the field in the future.

Speaker: Heather Fong

(DNP) W1-6 Multiple Facets of Nuclear Science | Les multiples facettes de la science nucléaire (DPN): Isotopes in Medicine | Les isotopes en médecine

305 Applying principles of radioimmunotherapy to cancer, infections and autoimmune disease

Radioimmunotherapy (RIT) uses monoclonal antibodies to deliver cytocidal radiation to the cells with the high precision. So far this approach has been used successfully in cancer arena. However, the principles of RIT could be applied to other, non-cancerous conditions where the diseased cells express the antigens which distinguish them from the healthy cells. Our laboratory is interested in developing RIT for several types of cancer, as well as for hard to treat infections and for autoimmune diseases such as multiple sclerosis. In cancer arena we are developing RIT for osteosarcoma, melanoma, some blood cancers and, most recently, colon cancer. When applying RIT to the fungal and bacterial infections, we are targeting antigens which are expressed on the surface of the microbial cells, such as polysaccharides, beta-glucans, or certain components of bacterial or fungal cell walls. Our recent work in this area includes RIT of opportunistic fungal infections and of bacterial infections of the prosthetic joints such as knees etc. in advanced animal models. In multiple sclerosis, which is a devastating autoimmune disease with disproportionally high incidence in Canada and especially in Saskatchewan, the activated T cells which attack the nerves protective sheath express high levels of program death recepto-1 (PD-1). Thus, we are utilizing PD-1 as our target for RIT of multiple sclerosis with the purpose of slowing down the disease progression and/or ameliorating its symptoms. In conclusion, the RIT approach can be applied to any disease for which a disease-specific antigen has been identified. With the help of modern technologies of antibody generation - making an antigen specific antibody can now be accomplished in a short period of time. RIT is technologically mature and can address the unmet needs of millions of patients with various conditions.

Speaker: Ekaterina Dadachova

306 Towards Availability, Safety, and Efficacy of Targeted Radiopharmaceutical Therapy

Radiopharmaceutical therapy has demonstrated encouraging clinical results in cancer treatment, which stimulated significant attention from the research community, clinicians, and the industry. The radiopharmaceutical therapy is expected to produce pointed effect on cancer lesions while avoiding toxicity to the healthy organs and tissues, which can result in better tolerability in comparison with standard-of-care treatments. To progress therapeutic radiopharmaceuticals from scientific curiosity to routine medicines, research and development is still required, including in large-scale production of useful radionuclides, optimization of targeting biological vectors, and understanding radiobiological effects and mechanisms of action for candidate drugs. This presentation will focus on (bio)medical aspects of nuclear sciences, and how new knowledge and tools can contribute to health outcomes.

Speaker: Dr Svetlana V Selivanova (Canadian Nuclear Laboratories)

307 Use of the Woodchuck (Marmota Monax) to Investigate Theranostics for Hepatocellular Carcinoma

Eastern woodchucks (groundhogs) infected with the Woodchuck Hepatitis Virus are a well-established animal model for interventional human hepatic neoplasm therapies such as embolization. The size of the woodchuck overcomes the geometric constraints on imaging and treatment delivery techniques associated with a murine model, and the viral-induced woodchuck tumors more closely resemble the immune features and complex microenvironment of human hepatocellular carcinoma (HCC). Researchers at the Western College of Veterinary Medicine have explored two potential targets for the radiopharmaceutical treatment of hepatocellular carcinoma in the woodchuck model: prostate-specific membrane antigen (PSMA) and somatostatin receptors (SSTRs). Gene expression in liver tumors and normal organs at risk was studied, and 68Ga and 64Cu-labeled small molecules were used to assess PET imaging uptake. Toxicity after [177Lu] PSMA-617 was assessed. On gross, imaging and microscopic levels, the liver tumors resembled human HCC, and no toxicity after a single dose of [177Lu] PSMA-617 was observed. Clinical progression, gene expression and positron emission tomography uptake were similar to that reported for human patients, confirming the potential of this animal model to investigate targeted radiotherapy for HCC.

Speaker: Monique Mayer (University of Saskatchewan)

308 Nuclear Physics: The Unsung Hero of Medical Diagnostics

X-rays and nuclear radiations have been the tools of medical diagnostics and therapy in addition to diverse applications in agriculture, industry and security. Starting from the early 20th century, the development of particle accelerators of diverse species of higher and higher energies along with nuclear reactors have enriched the nuclear tool chest.
Not only have we been able to take advantage of the photoelectric effect, positron annihilation and various kinds of scattering principles to calculate attenuation coefficients but we have been able to use these principles to improve radiation safety, leverage them to optimize radiation dose, and - above all – obtain better quality images for our patients. Our challenge is to keep up with the demand while maintaining our standard of imaging and minimizing dose to patients.

What initially started as X-ray photography of human bodies for diagnosing broken bones has expanded to image interiors of the bodies both for anatomical and functional imaging. Computed Tomography with X-rays produce detailed images which would have otherwise required several X-ray imaging exposures. Added to that are the Single Photon Computed Tomography (SPECT) and Positron Emission Tomography (PET) with ever more increasing number of medical isotopes.
Additionally, theranostics is a growing field of activity which facilitates real time imaging along with therapy to monitor the patient’s improvement.
All these developments also raise concern of the excessive radiation exposure to the patients and also radiology professionals. A good understanding of the diverse species of radiations and unique health risks of each species of radiation in conjunction with the affected human physiology are warranted.

Ongoing research, usually by medical physicists, will allow medical imaging to become more precise, efficient, and effective in patient care. A good understanding of nuclear radiation physics and technologies will contribute to help the medical professionals perform their duties with enhanced confidence. I will give a brief overview of the current state of the art of medical imaging and stress the need for better knowledge of nuclear physics by diagnostic radiologists.

References:
Moses, W. W. (2011). Fundamentals of Nuclear Physics in Imaging. Journal of Nuclear Medicine, 52(10), 1686-1696.
Nuclear Regulatory Commission. (2020). Overview of Nuclear Medicine and the Role of Radiopharmaceuticals in Diagnostic Imaging. U.S. NRC.
Mettler, F. A., & Bhargavan, M. (2009). Radiation Dose in Medicine: A Review of Current Issues. Health Physics, 97(5), 522-536.
Wang, G., & Li, H. (2011). X-ray Computed Tomography Imaging and the Role of Nuclear Physics in Diagnostic Radiology. Physics in Medicine and Biology, 56(7), R65-R101.

Speaker: Momina Mateen (The Ottawa Hospital, University of Ottawa)

(DPSR/DPA) W1-7 Private Sector Physics | Secteur privé Physique

(DCMMP) W1-8 Frontiers of Synchrotron Based Materials Physics | Frontières de la physique des matériaux basée sur le rayonnement synchrotron (DPMCM)

309 Advancing X-Ray Pair Distribution Function and Diffraction Capabilities at the Canadian Light Source

A series of significant advances in our acquisition and analysis of total scattering measurements at the Brockhouse X-Ray Diffraction and Scattering Sector (BXDS) of the Canadian Light Source has enabled atomic pair distribution functions (PDF) of unprecedented quality and sensitivity along with simultaneous high-resolution powder diffraction for Rietveld analysis. We have also managed to successfully produce excellent 3D-PDFs and conducted insitu studies. An overview of the new methods and capabilities will be presented. The PDF, Rietveld and 3D-PDF methods have been applied for the structure study of polycrystalline, nanomaterials, amorphous systems, and molecules in solution. This serves as an excellent analytical tool for structure determination and phase identification for exsitu, insitu and in-operando studies.
The performance of the current BXDS beamline will be compared with estimates based on potential CLS source upgrades as well as several fourth-generation high energy x-ray sources. Options for increasing capacity and performance will be presented. This will provide a better understanding of the comparison of 3rd generation synchrotrons and 4th generation synchrotrons as sources for PDF and high energy diffraction beamlines.

Speaker: Stefan Kycia (University of Guelph)

310 An Overview of X-ray Photon Correlation Spectroscopy

A new fourth generation of synchrotrons are currently coming on-line. The main improvement generated by these sources is an increase in coherence by two orders of magnitude. X-ray photon correlation spectroscopy (XPCS) is a technique that uses the coherence properties of x-rays to give detailed information about structural fluctuations and their dynamics at nanometer and shorter length scales, both in equilibrium and non-equilibrium systems. Fluctuations, Brownian motion or thermal noise are where materials store thermal energy. Fluctuations are what keeps materials in equilibrium and allows them to change in response to external changing conditions. After discussing the basis of XPCS, this talk will discuss the exciting new capabilities opened up by new sources such as fourth generation synchrotrons and x-ray free-electron lasers.

Speaker: Mark Sutton (McGill University)

311 Research examples from the inelastic scattering endstation of the REIXS beamline at CLS

The outer electrons in matter govern nearly all properties of materials including bonding, structure, magnetism, band gap, heat-, electrical- and superconductivity, and optical properties to name a few. The binding energies of these outer electrons reside in the soft X-ray range. Tuning the energy of synchrotron radiation to specific orbitals allows accessing these outer electrons and hence studying all these parameters.
The techniques available at the REIXS beamline at CLS to probe the electronic structure of new materials are soft X-ray absorption (XAS), X-ray emission (XES), Resonant inelastic X-ray scattering (RIXS), and X-ray excited optical luminescence (XEOL).
This talk will present an overview the large variety of very different questions and sample systems that can be explored with these soft X-ray spectroscopy techniques.
The topics will include low dimensional materials (Graphene, Silicene), LED materials, diluted magnetic semiconductors. Aside from the obvious parameters like electronic structure and band gap, we will show examples of how to study less obvious questions concerning defects and magnetism.
The list of examples is not intended to be complete but rather showcase the capabilities of the REIXS beamline.

Speaker: Alexander Moewes (University of Saskatchewan)

(DPP) W1-9 Plasma Physics and Technology | Physique et technologie des plasmas (DPP)

312 Splitting of Carbon Dioxide in Barrier Discharge: Influence of Discharge Geometry and Scalability Approaches

Speaker: Prof. Ronny Brandenburg

313 TPD

TBD

Speaker: Prof. Emile Carbon

314 TBD

TBD

Speaker: Prof. Jacopo Profili

315 DPP - Announcements

Speaker: Stephan Reuter (Polytechnique Montreal)

12:00 BSPC Judges Meeting

12:00 Break for Lunch (12h00-13h30) | Pause pour dîner (12h00-13h30)

CNILC Business Meeting | Réunion d'affaires de la CNILC

CAP/NSERC Liaison Meeting | Réunion de liaison ACP/NSERC

W-PLEN2 CAP-CRM Prize Plenary Session | Session plénière - Alexander Maloney, McGill U.

W-PLEN3 Applied Physics Medal Plenary Session | Session plénière - Richard Boudreault, Ude Sherbrooke

316 Physics as a Bridge: Biomimicry, Nanomaterials, and Innovation for Global Water Resilience

Industrial physics is, at its core, physics for the people. It is the application of fundamental principles to real-world challenges, with the aim of improving lives and preserving ecosystems. Among the most pressing of these challenges is the global scarcity of clean water—a crisis that disproportionately affects Indigenous communities, Arctic populations, and displaced refugees.
Over two billion people worldwide lack regular access to safely managed drinking water, according to the WHO and UNICEF. In Canada, 27 Indigenous communities remain under long-term drinking water advisories, while melting permafrost, saltwater intrusion, and increased sediment loads in surface water threaten supply security across the North. Groundwater, once considered stable, is increasingly impacted by climate-driven recharge variability, contamination from thawing soil layers, and industrial pressures. These environmental disruptions render traditional water infrastructure insufficient, especially in isolated or underserved regions where logistical access is limited, and costs are high.
This presentation highlights the development of a biomimetic, carbon-based nanomaterial engineered to extract potable water from the atmosphere. Inspired by the Namib beetle’s shell and xerophytic plant surfaces, this innovation enables water harvesting through capillary condensation and molecular selectivity, using nanoscale pores and minimal energy inputs. It is a tangible example of physics solving immediate human needs.

Speaker: Dr Richard Boudreault (Université de Sherbrooke)

14:00 Travel Time | Durée du voyage

(DPMB/DCMMP) W2-1 Soft Condensed Matter and Biological Physics | Matière condensée molle et physique biologique (DPMB/DPMCM)

317 Single-molecule analysis of collagen’s metastability

Collagen has been evolutionarily selected as the preferred building block of extracellular structures, where it constitutes approximately 20% of the body’s protein mass. Despite the inherent and surprising thermodynamic instability of individual proteins at body temperature, collagen manages to assemble into higher-order structures that provide mechanical support to tissues. We have been working to unravel the mystery of this dichotomy, by characterizing how different compositional features in collagen proteins influence their thermal metastability.

In this presentation, I’ll describe our use of AFM imaging and analysis to investigate the response of different types of collagen to changes in temperature. We observed structural changes including a time-dependent loss of these triple-helically structured proteins at body temperature. We found very few intermediate structures: in the absence of stabilizing interchain crosslinks, the thermally induced unfolding of collagen appears highly cooperative, leading to either apparently intact or unfolded structures. We identified a stabilizing feature in type IV collagen: interchain disulfide bonds (a “cystine knot”) that enhance protein metastability. This cystine knot is evolutionarily conserved in collagen IV, suggesting an important role for such a feature in preventing – or at least slowing – irreversible denaturation of metastable proteins.

Speaker: Nancy Forde

318 Hallmark of a liquid-liquid transition in supercooled water nanodroplets

Since the introduction of the liquid-liquid critical point (LLCP) hypothesis in 1992 to explain the anomalous properties of liquid water, numerous studies have been conducted to validate it. However, the LLCP’s occurrence at extremely supercooled temperatures and high pressures makes investigating the LLCP, and the associated liquid-liquid phase transition (LLPT) between a low-density liquid (LDL) and a high-density liquid (HDL), particularly challenging in experiments. Therefore, we adopt an alternative approach to observe LLCP manifestations in water nanodroplets, in which crystallization is suppressed, rather than in bulk water. Leveraging the Laplace pressure allows us to achieve high pressures by reducing nanodroplet radius. Employing the TIP4P/2005 water potential in molecular dynamics simulations, we identify hallmarks of a LLCP in nanodroplets containing only a few hundred molecules [1,2]. However, the small size required to produce the critical pressure of 185 MPa calculated for the model prevents a clear observation of a LLPT. We extend our study to water droplets ranging from a thousand to tens of thousands of molecules using the WAIL water model, revealing a critical pressure in nanodroplets at Pc=37 MPa. Bulk-like behavior is observed in nanodroplets of size N≳1000, and so we observe a sharp LLPT in droplet sizes of approximately Nc≈15,000. These findings are significant because if the LLPT in real water occurs at Pc ≲100 MPa, it opens the possibility of detecting a LLPT in water nanodroplets in experiments conducted at ambient pressure. To further investigate, we explore the potential for inducing a LLPT in nanodroplets containing tens of thousands of molecules using an inert gas as a pressurizing medium. Preliminary results indicate a transformation from LDL to HDL in the droplet core, as shown in Fig. 1, further supporting the feasibility of experimental LLPT detection in the absence of crystallization.
[1] S.M.A. Malek, P.H. Poole, and I. Saika-Voivod, Nat. Commun. 2018, 9, 2402
[2] S.M.A. Malek, P.H. Poole, and I. Saika-Voivod, J. Chem. Phys. 2019, 150, 234507

Speaker: Shahrazad Malek (University of the Fraser Valley)

Abstract_Shahrazad_Malek.pdf

Time-Dependence-Core-Density.pdf

319 Mechanically informed identification of shear instabilities in disordered covalent network glass

The mechanical behavior of oxide glasses is governed by their disordered covalent networks. Using a local mechanical probing technique, we show that regions with low local stress thresholds correlate strongly with soft spots in two-dimensional network glass samples. Despite its accuracy, this approach is computationally intensive, requiring mechanical simulations at each atomic site. To address this limitation, we develop purely geometrical indicators based on fabric tensors, leveraging topological characteristics of the elastic structural response. Our findings reveal a strong correlation between shear transformation zones and regions of maximal bond stretch variance when projected along the macroscopic deformation axis. While directional factors contribute to this relationship, bond stretch variance is the predominant factor, highlighting the invariant nature of shear transformation zones in network glasses. Since our indicators rely exclusively on geometric measures, they offer intuitive physical interpretation and can be extracted directly from structural images with minimal computational cost.

Speaker: Somar Shekh Alshabab (RWTH Aachen, Chair and Institute of General Mechanics)

320 Mucosal rheology in disease transmission

The biological complex fluid mucus plays a key role in the transmission of infectious diseases. In-host, mucus serves as a physical and biochemical barrier, excluding pathogens from reaching underlying susceptible cells. Externally, mucosalivary droplets transport pathogens between hosts, and transmission probability is intimately tied to the processes of aerosolization and virus stability in these biochemically rich droplets. In this talk, we will discuss our experimental and theoretical work related to mucosal rheology in both contexts. First, in the context of in-host barrier properties, we explore transport through mucus via our macrorheological and microrheological work in mucin gels, i.e. gels reconstituted from the primary macromolecular component of mucus, mucin. Next, in the external context, we present our preliminary experimental work on the impact of rheology and composition as well as ambient air conditions on fluid fragmentation. Throughout, we discuss the important implications of these processes on population-level dynamics of infectious disease.

Speaker: Caroline Wagner (Dept. of Bioengineering, McGill University)

(DQI/DPE/DPSR) W2-10 Q-STATE: Quantum Science, Technology, Applications, Training, and Education | Q-STATE : Science, technologie, applications, formation et éducation quantiques (DIQ/DEP/DPSR)

Quantum Sensing

321 Statistical and Machine Learning Methods for Quantum Sensing

The field of quantum sensing is built around the idea of using quantum systems to measure physical quantities, such as electric and magnetic fields, temperature and pressure, with resolutions and sensitivities beyond those achievable by classical sensors. Beyond fundamental demonstrations, practical quantum sensing technologies require fast measurements with high signal-to-noise ratio of what are usually—alas—‘fragile’ quantum states afflicted by decoherence and low throughput. Here, I present a series of approaches based on statistical analysis and machine learning to extract information—accurately and efficiently—from sets of data that are scarce and extremely noisy. I will present a few case studies that utilize color centers in diamond and hexagonal boron nitride to perform quantum-based measurements of temperature, optically detected magnetic resonance (ODMR) and fluorescence intermittency (blinking). I will show how the proposed methods can be successfully applied to measure certain physical quantities with better accuracy, higher resolution and/or overall fewer data points than standard approaches based on statistical inference. I will also discuss the increasingly important role machine learning is taking in the context of (quantum-based) data processing, with specific focus on both its merits and its limits.

Speaker: Carlo Bradac (Trent University)

322 Quantum Sensing Platforms for Real-World Applications

Quantum sensors leverage the unique quantum mechanical properties of light and matter to achieve unprecedented levels of sensitivity and accuracy in measurements of a wide variety of physical quantities. Several different technological platforms of quantum sensors are now commercially available and have applications across diverse industries including healthcare, environmental monitoring, navigation, and defence. The integration of quantum sensors into real-world commercial systems presents both technical challenges and promising opportunities for enhanced performance. In this talk, I will present some key quantum sensing platforms, their core operating principles, and highlight their advantages over classical sensing technologies. I will also discuss ongoing efforts in Canada and abroad to commercialize these technologies and make them more accessible to non-experts.

Speaker: Brynle Barrett (UNB)

323 Antimatter Meets Gravity — A Frontier in Quantum Sensing

Quantum sensing is an emerging approach for probing fundamental physics. In this talk, geared towards non-experts, I will explore the prospects of applying quantum sensing techniques to the study of antimatter.

The ALPHA experiment at CERN in Geneva recently observed the gravitational free-fall of antihydrogen—an atom composed of antimatter. To significantly improve the precision of such measurements, we have launched a new R&D initiative: HAICU (Hydrogen-Antihydrogen Infrastructure at Canadian Universities). HAICU uses hydrogen atoms as proxies for antihydrogen to develop atomic fountains as a stepping stone toward antimatter-based experiments. Our ultimate goal is to realize an anti-atomic interferometer for precision measurements of antimatter gravity.

Atomic interferometers are among the most sensitive quantum sensors available. I will highlight both the promise and the unique challenges of applying these techniques to antimatter atoms.

Speaker: Makoto Fujiwara (TRIUMF)

(DASP) W2-2 Student Workshop - Space Weather in Our Lives | Atelier pour les étudiants - La météo spatiale dans nos vies (DPAE)

Convener: David Themens (University of New Brunswick)

14:15 Spacecraft Operations - Andrew Howarth

14:45 Space Weather and the Power Grid - Hannah Parry

15:15 Radiation and Spacecraft - Ian Mann

(DAMOPC) W2-3 Current Trends/Hot Topics | Tendances actuelles/sujets d'actualité (DPAMPC)

(PPD) W2-4 Flavour Physics & Beyond | La physique des saveurs et au-delà (PPD)

324 New physics searches with the PIONEER experiment

Pions are fantastic tools to look for new physics. The PIENU experiment at TRIUMF (data completion in 2012) has provided, to date, the most precise experimental determination
of $R^{\pi}_{e/\mu}$ , the ratio of pions decaying to positrons relative to muons. While more than an order of magnitude less precise that the Standard Model (SM) calculation, the PIENU result is a precise test of the universality of charged leptons interaction, a key principle of the SM, constrains a large range of new physics scenario, and allows dedicated searches for exotics such as sterile neutrinos. I will present a short overview of the new physics constraints provided by $R^{\pi}_{e/\mu}$ measurements and introduce the next generation precision pion decay experiment in the making: PIONEER. This newly proposed experiment aims at pushing the boundaries of precision on $R^{\pi}_{e/\mu}$ and expanding the physics reach by improving on the measurement of the very rare pion beta decay $\pi^+\rightarrow \pi^0 e^+ \nu$. This will provide a new and competitive input to the determination of $|V_{ud}|$, an element of the Cabibbo- Kobayashi-Maskawa (CKM) quark-mixing matrix.

Speaker: Chloe Malbrunot (TRIUMF)

325 Progress towards a liquid xenon calorimeter for the PIONEER experiment

PIONEER is a next-generation pion decay experiment that will run at the Paul Scherrer Institute in Switzerland. The initial goal of PIONEER is to improve the precision of the pion branching ratio measurement $R_{e/\mu} = \frac{\Gamma \left(\pi^{+}\rightarrow e^{+} \nu_{e} (\gamma)\right)}{\Gamma \left(\pi^{+} \rightarrow \mu^{+} \nu_{\mu} (\gamma) \right)}$, a stringent, direct test of lepton flavour universality. To achieve this goal, PIONEER will employ a modern detector based on two key components: an active highly segmented target, and a large acceptance, 19 radiation length calorimeter. Two calorimeter technology options are being compared: LYSO crystals, and liquid xenon (LXe). Our team at TRIUMF is working on the R&D for the LXe option. Recent progress includes designing and testing components for a large LXe prototype detector and advancing simulations of the full calorimeter to assess its performance of decay positron energy and position reconstruction. In this talk, I will present results from GEANT4 simulations and give a status update of the R&D work.

Speaker: Dr Benjamin Davis-Purcell (TRIUMF)

326 The Chiral Belle Upgrade: Polarized Beams at SuperKEKB/Belle II

The Chiral Belle upgrade aims to introduce polarized electron beams to the SuperKEKB e+e− collider to enable a vast set of unique precision measurements using the Belle II detector. This includes the ability for Belle II to perform multiple high precision measurements of $\sin^2 \theta_W$ with left-right asymmetry measurements of pairs of electrons, muons, taus, charm and b-quarks produced via e+e- annihilation. Additionally, unparalleled precision measurements of neutral current universality ratios, and tau lepton properties, including the tau g-2, will be possible. The primary accelerator components required for this upgrade include a new polarized electron source, a compact spin rotator to rotate the electron spin from transverse to longitudinal at the interaction point, and a high precision electron beam Compton polarimetry system. This talk will discuss the unique physics measurements enabled by Chiral Belle and present the status of the ongoing R&D activities for realizing this upgrade.

Speaker: Savino Longo (University of Manitoba)

327 Design and Construction of a Polarized Electron Source for the Chiral Belle Upgrade to the SuperKEKB Collider

The SuperKEKB collider, operating at the $\Upsilon$(4S) resonance energy, delivers e$^+$e$^-$ collisions at the world's highest instantaneous luminosity for the Belle II experiment. A proposed long-term Chiral Belle upgrade aims to introduce a polarized electron beam in the High Energy Ring (HER), enabling a new and unique program of precision physics. This upgrade will facilitate precision measurements of electroweak parameters, such as sin$^{2}\theta_W$, with projected precision matching the LEP/SLC world average but at a center-of-mass energy of 10.58 GeV. The polarization upgrade also enables the world's highest precision measurements of the tau anomalous magnetic moment and the Michel parameters of tau leptonic decays, improving precision by orders of magnitude. These results open new avenues for the discovery of New Physics.

In order to introduce a polarized electron beam in the HER, a low-emittance polarized electron source is required. This source will supply transversely polarized electrons, allowing for separate data sets with opposite polarization states. This talk presents the design, construction, and testing of a GaAs-based polarized electron source for the preliminary phase of the upgrade.

The polarized electron source will be constructed and tested during the spring and summer of 2025. Upon approval, it will be integrated into the SuperKEKB injection room during the 2026 summer shutdown. The source will be used in a dedicated experiment to measure the polarization lifetime of electrons in the HER via Touschek scattering.

Speaker: Alexandre Beaubien

(DTP) W2-5 Hot Topics in Theoretical Physics | Sujets d'actualité en physique théorique (DPT): Quantum Gravity and Information | Gravité quantique et information

328 Cosmology from Holography

We describe how the holographic approach to quantum gravity might be used to give a full-fledged quantum gravity description of big-bang cosmology. The resulting cosmological models have a negative cosmological constant but can generically explain late-time acceleration due to the potential energy of time-dependent scalar fields associated with relevant scalar operators in the CFT. If such models can describe realistic cosmology, they would predict time-dependent dark energy that decreases and eventually switches sign, leading to a big crunch. We show that such decreasing dark energy is consistent with and perhaps even preferred by scale factor evolution data deduced from supernova and BAO observations.

Speaker: Mark Van Raamsdonk (The University of British Columbia)

329 Quantum gravity meets quantum cryptography

The AdS/CFT correspondence gives a remarkable description of a system with gravity in terms of a non-gravitating, quantum mechanical theory. Importantly, the geometry of the gravitating theory is recorded into the pattern of entanglement in the dual quantum mechanical system. This gives a new way of thinking about gravitational physics in terms of entanglement, but also gives a geometrical way of reasoning about entanglement. I present some insights into aspects of entanglement and quantum information that are revealed by the AdS/CFT correspondence. In particular I show how apparently unrelated aspects of quantum cryptography can be seen to be related via this geometrical view of entanglement. I also review how these connections to cryptography give insights into AdS geometry.

Speaker: Alex May (University of British Columbia)

330 A singularity free classical theory of gravity

We present a classical theory of gravity, which is singularity free at short distances and reduces to General Relativity at large distances. We discuss its implications for quantum gravity and cosmology.

Speaker: Saurya Das (University of Lethbridge)

(DNP) W2-6 Multiple Facets of Nuclear Science | Les multiples facettes de la science nucléaire (DPN): Isotopes in Environment | Isotopes dans l'environnement

331 From Theory to Practice: Nuclear Safety in High-Grade Uranium Mines

This presentation bridges the gap between theoretical nuclear physics and the practical realities of ensuring worker safety in high-grade uranium mines. High-grade uranium ore presents unique challenges in radiation protection due to gamma radiation, radon gas, and long-lived radioactive dust (LLRD). This necessitates a multi-faceted approach to radiation protection, combining sophisticated modelling with robust engineering and administrative controls.
We will explore the key radiation hazards encountered in high-grade uranium mining, focusing on the physics underpinning their behaviour and impact. This includes a discussion of gamma radiation fields, radon emanation from ore bodies and surrounding rock formations, and the decay chains contributing to LLRD exposure.

The presentation will detail the strategies employed to mitigate these hazards. This covers predictive modelling of radon and gamma radiation, the application of advanced engineering controls such as raiseboring and jet boring techniques designed to minimize exposure, and the implementation of rigorous controls including radiation work permits and a comprehensive code of practice. We will demonstrate how these controls, used in conjunction with comprehensive dosimetry monitoring and a robust radiation protection program, maintain worker doses well below regulatory limits.

This presentation offers a real-world perspective on applying health physics in one of the most regulated industries.

Speaker: Jason Sadowski (Cameco Corporation)

332 Advanced Fission Reactors in Canada

A number of reactor designs are under consideration in Canada for pre-licensing/licensing by the Canadian Nuclear Safety Commission. Although these reactors build on concepts that were adopted during the early era of nuclear power, they are advanced by introducing features to overcome the cost overruns and delays typically associated with nuclear power plant constructions. Inherent and passive aspects are also introduced to enhance safety and reliability. To reduce financial risk and to accommodate districts with modest power needs, small reactor modules, with power of 300 MW(e) or less, are favoured. Microreactors (of about 10 MW(e) or equivalent) are designed to be self-regulating so that they can be used in remote and isolated communities and in industrial outlets without refuelling for a decade or more. There is still however interest in reactors with power in the GW(e) range to take advantage of the economy of scale. Reactors that can burn spent nuclear fuel and/or breed fissile materials are also reemerging to reduce nuclear waste and sustain the nuclear fuel cycle, while high-temperature reactors are contemplated to raise thermal efficiency and meet industrial process heat demands. Whatever the size or type, modularity is advocated as an approach to reduce construction costs and duration.

This presentation reviews the reactor designs under consideration in Canada; in terms of the novel features that help meet the goals set by the Generation IV Forum. These goals focus on supporting enhanced sustainability, improved economics, excelled safety and reliability, ensured proliferation resistance, and increased physical protection. The various concepts of modularity will also be explored, showing that modularity in reactors is best achieved by design intensification/integration to provide compact modules or in the design of auxiliary systems outside the nuclear island, and via modular fabrication and construction.

Speaker: Esam Hussein (University of Regina)

333 Power System Simulations to Analyze the Flexible Operation of Small Modular Reactor-Based Nuclear Power Plants for Electricity and Energy Applications (Heating and Hydrogen Production)

Nuclear power has traditionally served as a baseload power source, but the evolving energy landscape demands greater operational flexibility. Small Modular Reactors (SMRs) present a promising solution, not only for power generation but also for enhancing grid stability by complementing variable renewable energy sources. The increasing penetration of intermittent generation, such as wind and solar, shifts the load curve and introduces challenges that require nuclear power plants to dynamically adjust their output. However, frequent control rod adjustments to enable flexible operation can lead to issues such as thermal fatigue, accelerated component aging, erosion and corrosion of hydraulic systems, core power redistribution, and fission product poisoning. These challenges underscore the need for an optimized control rod strategy. This study explores alternative methods to enhance operational flexibility in SMRs, including the integration of bypass systems to manage minor fluctuations and the utilization of variable thermal and electrical loads to balance excess steam generation. One approach involves directing surplus thermal energy toward district heating, ensuring efficient heat utilization while maintaining reactor performance. Another strategy leverages surplus energy for hydrogen production via electrolysis, promoting sector coupling and expanding nuclear energy’s role beyond electricity generation. By adopting these approaches, SMRs can play a crucial role in creating a resilient, adaptive and sustainable energy future.

Speakers: Ms Deepa Upadhyaya Subedi (University of Saskatchewan), Prof. Ramakrishna Gokaraju (University of Saskatchewan)

Multiple facets abstract_3.pdf

334 Intermediate-Level Waste Disposal from Small Modular Nuclear Reactors in Saskatchewan

The role of engineered barriers, and certain geological and environmental engineering aspects, including Saskatchewan context, that can be used to isolate radioactive nuclides from the biosphere in nuclear waste management.

Speaker: Mr S. Hakan Armagan (College of Engineering, University of Saskatchewan)

Abstract-Nuclear waste management-S Hakan Armagan.pdf

(DPSR/DPA) W2-7 Private Sector Physics | Secteur privé Physique

(DCMMP) W2-8 Frontiers of Synchrotron Based Materials Physics | Frontières de la physique des matériaux basée sur le rayonnement synchrotron (DPMCM)

335 Synchrotron X-ray Scattering studies of alpha-RuCl3

In the last decade, alpha-RuCl$_3$ has been extensively studied as a possible realization of the Kitaev quantum spin liquid state, an elusive new state of matter that could be useful for applications in quantum technologies. However, inconsistent experimental reports have made it challenging to understand its true ground state. In this talk, we will give a brief overview of the current status of research on alpha-RuCl3 and discuss recent experimental developments and a few surprising findings using various X-ray scattering techniques. Our high-resolution X-ray diffraction studies carried out at the CLS allowed us to determine its low-temperature crystal structure, which explains the observed temperature dependence of the magnetic anisotropy. Resonant Elastic X-ray Scattering (REXS) studies allow us to determine the magnetic structure of this material, which turned out to be crucial for understanding the underlying magnetic Hamiltonian of this material. Finally, our resonant inelastic X-ray scattering (RIXS) data revealed the non-local nature of the electronic states in this material.

Speaker: Prof. Young-June Kim (University of Toronto)

336 X-Ray Diffractive Optics for Imaging and Other Applications

The use of X-ray diffraction for manipulating x-ray beams extends to nearly to the beginning of the discovery of x-rays primarily to prepare or analyze x-ray beams. The synchrotron provides an excellent environment to develop x-optics given the large x-ray energy range, the inherent collimation along with the dedicated environments for data acquisition and control. I, my students and colleagues have been involved in several x-ray diffractive optics development projects mostly for biomedical imaging applications at the Canadian Light Source. These projects span from contrast element imaging (spectral K-Edge Subtraction), phase-preserving vertical beam expansion, horizontal beam compression, wide energy range spectral imaging, wide field speciation or near edge imaging and including a discover that led to the ability to measure the synchrotron source position, angle, source size and source divergence at a single location in a beamline. An overview of some of these projects and possible connection to new generations of x-ray sources will be discussed.

Speaker: Prof. Dean Chapman (University of Saskatchewan)

337 Insights into High-Density Intermetallic Solid Solutions Using Synchrotron Radiation

The formation of solid solutions at ambient conditions is predominantly dictated by atomic size disparities and electronegativity y, as outlined by the Hume-Rothery and Miedema empirical rules. However, the application of high pressure notably enhances density, leading to significant changes in electron distribution and altering the conditions necessary for alloy formation. To explore binary alloys at elevated densities, we demonstrate the application of synchrotron radiation for a systematic investigation into the alkali metal potassium (K) and various transition and noble metals (M) under high-pressure environments. In this study, X-ray diffraction using synchrotron radiation was employed to observe and characterize novel alloys within the K-M systems, focusing on their crystalline structures and phase change and stability. A thorough analysis of these structures and their electronic configurations revealed that the novel K-M compounds discovered here cannot be adequately explained by the existing empirical rules governing alloy formation.

Speaker: Serge Desgreniers

(DPP) W2-9 Plasma Physics and Technology | Physique et technologie des plasmas (DPP)

338 Design of Collective Thomson Scattering system on Keda Torus eXperiment (Reverse Field Pinch machine in China)

Collective Thomson scattering (CTS) is a powerful diagnostic technique with the capability to provide bulk ion temperature and ion composition of plasma with high temporal and spatial resolution. It has been developed in many fusion devices such as ASDEX, TEXTOR, W7-X, and ITER etc.
CTS is the elastic scattering process of electromagnetic waves by electrons with collective motions. For CTS diagnostic system in fusion plasmas, the frequency of probe beam is usually set in millimeter-wave band in order to satisfy the condition that Salpeter parameter $\alpha=1/|\vec{k} _\delta |\ \lambda_D$ exceeds unity. Here, $\lambda_D$ represents the electron Debye length, while $\left|{\vec{k}}_\delta\right|\approx\left(4\pi\sin{\frac{\theta}{2}}\right)/\lambda_0$ denotes the differential scattering vector number, $\lambda_0$ is the probe wavelength, and $\theta$ is the scattering angle.
Due to the extremely small scattering cross section, high-power pulsed source providing the probe beam and high-sensitivity electronics module receiving the weak scattering radiation are two key issues for CTS. A plused gyrotron source with peak power 1MW/center frequecy 60GHz/pulse length 5us has been built. In the bench test, the source demonstrated excellent repeatability and monochromaticity with a linewidth around 0.2MHz, which provide a solid foundation for the subsequent CTS development. The central frequency is deliberately chosen to be 60 GHz, which can effectively avoid the interference of electron cyclotron emission in the KTX device and improve the signal-to-noise ratio. In terms of the receiving module, diverging from the conventional signal - processing architecture in which mixing followes by amplification, our approach is to implement amplification prior to mixing. This technical pathway has notably enhanced the sensitivity of the intermediate - frequency receiving system. Specifically, a gain of no less than 40 dB has been attained, and the minimum detectable signal amplitude is approximately -65 dBm.
An improved genetic algorithm with the new fitness function has been developed to decompose CTS scattering spectra, which significantly reduces the dependence of the CTS data processing on the information of other plasma parameters.

Speaker: Jinlin Xie (University of Science and Technology of China)

339 Synchrotron Grazing Incidence X-ray Analysis of PIII Implanted Helium and Deuterium Tungsten, Tungsten-Nickel-Copper, and Tungsten-Tantalum as Plasma-facing Components

Tungsten (W) is considered the optimal choice for plasma-facing components (PFCs) in fusion devices due to its high melting point, excellent mechanical properties, and minimal erosion rate. However, studies have shown that W undergoes extreme morphological change when it is bombarded by a high fluence of low-energy ions from helium (He) and deuterium (D) plasmas. To maintain W properties, its alloys—tungsten heavy alloys (W-HA), (90$\%$W-6$\%$Ni-4$\%$Cu), and tungsten-tantalum (W-10$\%$Ta) were investigated as PFCs. The microstructural analysis of He and D ion implanted W and its alloys was conducted using synchrotron grazing incidence X-ray diffraction (GIXRD) and X-ray reflection (GIXRR) techniques at the Canadian Light Source (CLS). The analysis was performed at different grazing incidence angles, 0.5$^{\circ}$, 1$^{\circ}$, 3$^{\circ}$, 5$^{\circ}$ and 7$^{\circ}$ to study near-surface defects. The implantation results unmistakably show that He$^+$ ions inflict significantly more near-surface strain, peak broadening, and distortion than D$^+$ ions, especially up to a depth of 120 nm. At a depth of 1000 nm, $\mathrm{D^+}$ implanted pure-W exhibits a severely deformed (110) GIXRD diffraction peak. W-Ta and W-Ni-Cu alloys did not exhibit (110) peak distortion. The GIXRR revealed that X-ray reflection is lower from implanted samples than un-implanted, confirming the increased surface roughness in ion-implanted W and W-alloy target materials. The results indicate that the negative effects of He$^+$ and D$^+$ ions can be mitigated by alloying W with suitable components.

Speaker: tahreem yousaf

340 High-speed vacuum ultraviolet imaging system for edge plasma in EAST

A high-speed vacuum ultraviolet imaging (VUVI) system for edge plasma studies is being developed on the Experimental Advanced Superconducting Tokamak (EAST). Its key optics is composed of an inverse type of Schwarzschild telescope made of a set of Mo/Si multilayer mirrors, a micro-channel plate (MCP) equipped with a P47 phosphor screen and a high-speed camera with CMOS sensors. In order to remove the contribution from low-energy photons, a Zr filter is installed in front of the MCP detector. With this optics, VUV photons with a wavelength of 13.5 nm, which mainly come from the line emission from intrinsic carbon (C vi: n = 4-2 transition) or the Ly-$\alpha$ line emission from injected Li iii on the EAST, can be selectively measured two-dimensionally with both high temporal and spatial resolutions. Interesting events in the edge plasma, such as ELMs, dust etc, have been captured by this system. Their dynamics have been studied using the imaging data [1][2]. Based on the success of the VUVI system, a multi-spectral extreme ultraviolet imaging (MEUVI) system is being developed to measure the Te profile in the edge region [3]. Line emissions from six wavelengths are measured simultaneously in such a single telescope, in which each pair of primary and secondary mirrors are projected nearly 1/6 sector in the arc vector direction. Electron temperature can be measured by using this optics. We will present the experimental results obtained using the high-speed VUVI system and recent progress of the MEUVI system.

[1] T.F. Ming, T. F. Tang, Q.Q. Shi et al 2022 Nucl. Fusion 62 126039
[2] S.W. Hou, T.F. Ming, Q.Q. Shi, et al Plasma Sci. Technol. 25 (2023) 055101
[3] S.W. Hou, T.F. Ming, H.X. Si et al, Fusion Eng. Des. 208 (2024) 114681

Speaker: Tingfeng Ming (Institute of Plasma Physics, Chinese Academy of Sciences)

341 Acceleration Dynamics of KTX-CTI Compact Torus Plasma

Compact torus (CT) injection, a critical technology for core fueling in magnetic confinement fusion, requires precise optimization of its acceleration dynamics to achieve efficient plasma delivery. This study presents a comprehensive investigation of CT acceleration in the newly developed KTX-CTI injector integrated into the Keda Torus eXperiment (KTX) reversed field pinch device. By employing the instantaneous frequency analysis and circuit analysis, we reveal the dynamic interplay between electromagnetic drivers and plasma behavior during acceleration. A novel variable-mass acceleration model is introduced, challenging the conventional point-model assumption of CTs as dimensionless current sheets. Experimental results demonstrate that CTs undergo significant spatial expansion during acceleration, progressively accumulating mass from the surrounding environment. This mass-loading effect, driven by magnetic-plasma coupling and circuit-load interactions, fundamentally alters acceleration efficiency and trajectory. The findings underscore the necessity of accounting for time-dependent mass evolution in CT injector design, offering critical insights for optimizing fueling speed, mass control, and energy efficiency in fusion reactors. This work advances the predictive capability of CT dynamics and provides a framework for next-generation injector development, directly impacting the scalability of magnetic confinement fusion technologies.
[1].Tao Lan, Chen Chen et al. Preliminary compact torus injection experiments on the Keda Torus eXperiment reversed field pinch, Plasma Sci. Technol. 26, 105102 (2024).
[2].Qilong Dong, Jie Zhang, Tao Lan et al. Effects of vacuum magnetic field region on the compact torus trajectory in a tokamak plasma, Plasma Sci. Technol. 26, 075102 (2024).
[3].Chen Chen, Tao Lan et al. Development of a compact torus injection system for the Keda Torus eXperiment, Plasma Sci. Technol. 24, 045102 (2022).

Speaker: Prof. Tao Lan (University of Science and Technology of China)

342 Development of KTX reversed field pinch facility in China

Keda Torus eXperiment (KTX), a medium-sized reversed field pinch (RFP) device commissioned in 2015 at the University of Science and Technology of China, serves as a complementary facility to existing international RFP programs. Designed for plasma confinement optimization through enhanced wall conditions and high plasma currents up to 1 MA, KTX has undergone systematic upgrades in critical systems including ohmic power supply, density regulation, edge magnetic feedback control, and plasma diagnostics. Significant technical advancements include the upgrade of poloidal field coil power supply to 5 MJ stored energy, enabling plasma currents exceeding 500 kA with peak heating power reaching 30 MW. A sophisticated 96-channel active feedback control system has been implemented for effective MHD mode suppression and error field correction, extending plasma current duration beyond 100 ms (exceeding five times the shell time constant). The installation of a dual-biasing electrodes system facilitates edge electric field manipulation for turbulence transport studies and rotation control. A novel compact torus injection system (KTX-CTI) with midplane horizontal injection capability has been developed for multi-parameter plasma control, including fueling optimization, current profile modification, and momentum/helicity injection. For three-dimensional (3D) physics investigations, advanced diagnostic suites have been deployed including Thomson scattering, terahertz polarimeter/interferometry, and dual-foil soft X-ray imaging systems. Current research initiatives on KTX focus on two primary directions: 1) Plasma confinement enhancement through MA-level current operation, and 2) Investigation of universal toroidal confinement physics applicable to tokamaks and stellarators, addressing challenges such as high-density operational limits, electromagnetic turbulence transport mechanisms, and 3D magnetic field effects. Combined experimental and computational efforts aim to provide multi-faceted insights into critical physics issues for next-generation fusion reactor development.

Speaker: Prof. Ge Zhuang (University of Science and Technology of China)

15:45 Health Break with Exhibitors | Pause santé avec les exposants

(DPMB/DCMMP) W3-1 Soft Condensed Matter and Biological Physics | Matière condensée molle et physique biologique (DPMB/DPMCM)

343 A helical fluid in confined quasi-one-dimensional hard spheres

Hard spheres confined to long, narrow, cylindrical channels spontaneously form helical structures. We use molecular dynamics simulation to show that the thermodynamics, structure and dynamics of these systems are dominated by the presence of topological defects that reverse the local twist direction of the helix. The equilibrium fluid exhibits two heat capacity maxima related to structural crossovers associated with the onset of helix formation at low densities and a Schottky-like anomaly caused by the rapid elimination of defects at high density. As expected, the fluid remains achiral over the densities studied. Structural relaxation in the system occurs through the creation, diffusion and elimination of the defects, which leads to a stretched exponential decay in the local twist auto-correlation function and a fragile-strong fluid crossover located at the high density heat capacity maximum. However, introducing excess helical twist into the system leads to the formation of a chiral fluid characterized by the presence of loosely bound defect pairs which become more tightly bound with increasing excess helical twist. The local twist auto-correlation function in the chiral fluid decays as a power law at long times while the translational correlation function decays exponentially like a fluid.

Speaker: Richard Bowles (Department of Chemistry, University of Saskatchewan)

344 Liquid-liquid phase transition in supercooled water: Recent progress from simulations and experiments

Liquid water exhibits a large number of unusual properties, many of which become pronounced in cold and supercooled water, such as the density maximum at 4 C. Based on computer simulations, it has been proposed that a liquid-liquid phase transition (LLPT) occurs in supercooled water, in which two phases of liquid water become distinct below a critical point currently estimated to occur at approximately 210 K and 100 MPa. Such a LLPT provides a unified and thermodynamically consistent explanation of many of water’s anomalies, including the behavior of amorphous solid water. While it is now firmly established that a LLPT occurs in realistic (including quantum-based) water simulations, attempts to provide a definitive experimental demonstration are frustrated by rapid ice crystallization. After reviewing the status of the LLPT hypothesis, I will discuss recent simulations that seek to identify novel ways to detect the LLPT in real water, and recent experiments that attempt to do so.

Speaker: Peter Poole (St. Francis Xavier University)

345 Droplets as cohesive granular materials at the edge of stability

Granular materials, ranging from rice and sand to fine powders, and their large-scale manifestations such as earthquakes, landslides, and avalanches, are simultaneously commonplace and deceptively complex. These complex systems exist at the boundary between solid-like and fluid-like, and they are often highly nonlinear, dissipative, and at the edge of stability. Additionally, these materials can offer macroscopic insights into behaviors typically associated with molecular liquids and solids. In recent years we have developed a method to produce cohesive microscopic droplets which can form perfect crystalline or disordered aggregates. These granular aggregates provide model systems for studying various physical phenomena that are not accessible by investigating molecular systems. The experiments enable us to study broad questions which relate to real-world problems like predicting the failure and fracture of materials, flow through a hopper, and the size and temporal distribution of avalanches.

Speaker: Prof. Kari Dalnoki-Veress (Department of Physics & Astronomy, McMaster University and Gulliver Laboratory, ESPCI Paris)

Kari_D-V_abstract_CAP2025.pdf

(DQI/DPE/DPSR) W3-10 Q-STATE: Quantum Science, Technology, Applications, Training, and Education | Q-STATE : Science, technologie, applications, formation et éducation quantiques (DIQ/DEP/DPSR)

Quantum Networks and Quantum Key Distribution

346 Invited Talk by Connor Kupchak on Quantum Networks

347 Talk and Workshop with Thomas Jennewein and Ian D'Souza: QKD and beyond

(DASP) W3-2 Student Workshop - Space Weather in Our Lives | Atelier pour les étudiants - La météo spatiale dans nos vies (DPAE)

Convener: Daniel Billett (University of Saskatchewan)

16:15 Space Weather and Aviation - Robyn Fiori

16:45 Spacecraft Drag - Daniel Billett

17:15 Space Weather Impacts on Communications, Remote Sensing, and Navigation - David Themens

(DAMOPC) W3-3 Current Trends/Hot Topics | Tendances actuelles/sujets d'actualité (DPAMPC)

348 Communicating optics using a multimodal, textbook centered, approach

We have recently completed a comprehensive revision of the classic optics textbook, Pedrottis' Introduction to Optics, intended for upper-year undergraduate and incipient graduate students in physics and engineering. There were many facets to this project, which involved strong collaboration among us, supported by a team at Cambridge University Press & Assessment. The goal of the project was to construct an effective pedagogical package for students and instructors of optics that offered distinct tools to aid learning, each presented within a philosophy of consistent communication. Tools include scientifically-accurate interactive animations, end-of-chapter integrated testlets, expansive figure captions, and targeted footnotes to assist the more curious, or the slightly bewildered, learner. In this talk I describe the motivation behind the project and the structure of the resulting textbook, together with strategies we employed to ensure consistent communication, to select new material of interest, to design and implement accompanying interactive animations, and to compose and assess the integrated testlets. The pedagogical benefits of each of these are examined.

Speaker: Rayf Shiell (Trent University)

349 Developments in antihydrogen laser cooling and future high-precision studies

One of the most enduring mysteries in contemporary physics is the disparity in matter and antimatter within the observable universe. The Standard Model of particle physics posits that the Big Bang generated an equal quantity of matter and antimatter. However, cosmological observations reveal that the antimatter-to-matter ratio is approximately 10-8. Any discrepancies in the properties of matter-antimatter pair particles could potentially indicate a violation of CPT symmetry, potentially providing an explanation for the universe’s apparent preference for matter. The ALPHA (Antihydrogen Laser PHysics Apparatus) collaboration, at CERN (European Organisation for Nuclear Research), conducts research on antihydrogen’s atomic spectrum and interactions within Earth’s gravitational field.

Recent publications by the ALPHA collaboration have demonstrated the operational functionality of all the apparatus’s components. Measurements have been conducted on the hyperfine transition, 1S-2S, 1S-2P, laser cooling, and gravitational interaction involving trapped antihydrogen within the ALHPA2 and ALPHAg apparatus. Notably, we have recently published a detailed analysis of the 1S-2S line-shape of laser-cooled antihydrogen samples. Future high-precision studies of antihydrogen at ALPHA will necessitate enhanced laser cooling techniques for the trapped antihydrogen samples and precise diagnostics of their energy levels to achieve comparable results with equivalent studies conducted on hydrogen.

In this presentation, I will give an overview of the research done by ALPHA. The focus will be on the ALPHA2 and ALPHAg experimental apparatuses. I will describe the laser cooling techniques employed, particularly the 121 nm pulsed laser system. Furthermore, I will discuss the temperature diagnostics of these trapped samples. Cold and well-diagnosed antihydrogen samples are indispensable for high-precision measurements, directly influencing the accuracy of ALPHA’s endeavours. Finally, I will address the significance of direct hydrogen-antihydrogen comparisons, which provide pivotal tests of fundamental physics, such as CPT symmetry, and enhance our comprehension of matter-antimatter interactions.

Speaker: Dr Andrew Evans (University of British Columbia (CA))

350 Measuring the Schiff Moment with 227ThF+

The Standard Model of particle physics is one of the most successful models of the universe, yet it is known to be incomplete. Substantial efforts on the theoretical front introduce new physics through extensions of the Standard Model. Advances in quantum control of molecules have resulted in some of the most stringent constraints on physics beyond the Standard Model [1,2]. Extensive molecular spectroscopy of $^{232}$ThF$^+$ [3-5] has been motivated by the immense sensitivity of the molecule to the electron’s electric dipole moment and promised long coherence time in the molecular science state [4-7]. Building upon this work, we propose the measurement of the Schiff moment, a physical quantity that could hint at new physics, on the isotopologue $^{227}$ThF$^+$. Herein, we discuss the complications of working with radioactive $^{227}$Th and provide a teaser of the status of the experiment.

[1] L. Caldwell, et al. Systematic and statistical uncertainty evaluation of the HfF+ electron electric dipole moment experiment. Physical Review A 108, 012804 (2023).
[2] T. S. Roussy, et al. A new bound on the electron’s electric dipole moment. Science 381, 46-50 (2023).
[3] Y. Zhou, et al., Visible and ultraviolet laser spectroscopy of ThF, Journal of Molecular Spectroscopy 358, 1 (2019).
[4] K. B. Ng, et al., Spectroscopy on the electron-electric-dipole-moment–sensitive states of ThF+, Physical Review A 105, 022823 (2022).
[5] D. N. Gresh, et al., Broadband velocity modulation spectroscopy of ThF+ for use in a measurement of the electron electric dipole moment, Journal of Molecular Spectroscopy 319, 1 (2016).
[6] Skripnikov, L. V., and A. V. Titov. Theoretical study of ThF+ in the search for T, P-violation effects: Effective state of a Th atom in ThF+ and ThO compounds. Physical Review A 91, 042504 (2015).
[7] Denis et al., Theoretical study on ThF+, a prospective system in search of time-reversal violation. New Journal of Physics 17, 043005 (2015).

Speaker: Kia Boon Ng (TRIUMF)

(PPD) W3-4 Flavour Physics & Beyond | La physique des saveurs et au-delà (PPD)

351 New Measurement of the K⁺ → π⁺νν̅ Branching Ratio by the CERN NA62 Experiment

The K⁺ → π⁺νν̅ decay is a highly suppressed flavor-changing neutral current dominated by short distance dynamics. The predicted Standard Model (SM) branching ratio is (8.4 ± 1.0) × 10-11. Given its properties, this process is often called a "golden mode" for New Physics searches.

The CERN SPS NA62 experiment has now achieved a signal significance above five sigmas. The branching ratio agrees with the SM predictions within 1.7 σ.

In this talk, I will review the NA62 K⁺ → π⁺νν̅ searches based on data collected in 2016–2018 and 2021–2022.

Speaker: Bob Velghe (TRIUMF (CA))

352 The Flavour of High-Energy Neutrinos

We now have over a decade of high energy neutrino data from the IceCube telescope at the South Pole. These neutrinos convey information about their sources, propagation, and interaction via directional, energy, and flavour. I will discuss what we can learn about the flavour composition of these events with current and future telescopes, and what flavour can tell us about neutrino sources and potential new physics in the neutrino sector. I will end with a closer look at the neutrino/antineutrino ratio, accessible via the Glashow resonance, which can break important degeneracies in flavour space and provide a potentially unique probe of new physics.

Speaker: Aaron Vincent (Queen's University)

353 X17 – or the Search for New Physics in Nuclear Transitions

Rare nuclear transitions are well suited to explore weakly-coupled New Physics and portals into the dark sector at the MeV-scale. In this talk the so-called X-17 Anomaly will be discussed, which is a significant discrepancy reported by the ATOMKI collaboration in the observation of decays of excited 8Be, 4He and 12C nuclei to their ground states via internal e+e- pair creation. The anomaly, which appears in the angular distribution of the e+e- pairs, can be explained by the emission of a neutral boson with a mass of about 17 MeV/c2, decaying into e+e-. The ATOMKI results and their interpretations are discussed, as well as the status of follow-up experiments, among which an ongoing project at the Montreal Van de Graaff accelerator facility.

Speaker: Prof. Viktor Zacek (University of Montreal)

(DTP) W3-5 Hot Topics in Theoretical Physics | Sujets d'actualité en physique théorique (DPT)

(DNP) W3-6 Multiple Facets of Nuclear Science | Les multiples facettes de la science nucléaire (DPN): Evolving Landscapes of nuclear technology | Évolution des paysages de la technologie nucléaire

354 Proton Therapy and Beyond - Defining Future Accelerator Technology for Medical Applications in Canada

For over five decades, TRIUMF has been at the forefront of accelerator-driven secondary particle production, cementing Canada’s role as a global leader in supplying essential accelerator technology for radioisotopes, neutrons, photons, and muons. These particles power groundbreaking research in nuclear, particle, and astrophysics, as well as solid-state physics and an expanding range of medical applications.

With the global rise in cancer incidence, the clinical demand for particle accelerators continues to grow. Simultaneously, emerging modalities in both diagnostics and therapy are driving the need for novel accelerator systems tailored to the unique requirements of medical applications. At TRIUMF, ongoing research and development efforts are focused on advancing accelerator platforms that support the exploration and optimization of new treatment and imaging techniques. These efforts are coupled with a robust technology translation pipeline that brings innovations from the lab bench to commercial deployment and clinical integration, where reliability and usability are critical.

Current initiatives at TRIUMF also include the development of advanced detection methods, innovations in dosimetry, and the production of novel radioisotopes. These are being evaluated through preclinical studies and early-phase clinical trials, reinforcing TRIUMF’s commitment to improving patient outcomes and enabling the next generation of accelerator-based medicine.

Speaker: Alexander Gottberg (TRIUMF (CA))

355 Nuclear physics detection solution, from double beta decay to forest fires

The search for neutrinoless double beta decay in liquid Xenon led to the development of a new generation of single photon detectors with deep UV sensitivity and extremely low power consumption. The emergence of digital Single Photon Avalanche Diode (SPAD) arrays also called digital SiPMs is starting to revolutionize many sensing applications, including high rate neutron detection and even air analysis. We will review how the development of digital SPAD arrays for nuclear physics is promising to enable the characterization of the fusion plasma temperature that the company General Fusion is hoping to produce. And we will discuss how ultra low power air analysis sensor enabled by digital SPAD arrays may help protect Canada against devastating forest fires in the coming decades.

Speaker: Dr Fabrice Retiere (TRIUMF)

356 Efficacy of Radiation Hardening by Design Techniques on an ASIC 32-bit RISC-V Microcontroller

A 32-bit RISC-V microcontroller is designed and fabricated at a 22-nm FD SOI node using Radiation Hardening by Design Techniques. The device features 512 KB of on-board memory and can run at a clock speed of ~300 MHz. The device also supports a rich set of interface options. Using both architectural changes as well as more complex standard cell replacements, the device shows strong reliability against SEE induced faults in broad-beam testing. The device is also functional after 100 kRad of testing using high-energy protons. Results from irradiation experiments suggest that the core and peripherals are extremely robust, with SEFIs originating from accumulated memory errors. With proper software design, the device can be SEFI immune up to an LET of 96.30 MeV·cm2/mg.

Speaker: Christopher Elash (University of Saskatchewan)

Efficacy of Radiation Hardening by Design Techniques on an ASIC 32-bit RISC-V Microcontroller.pdf

(DPSR/DPA) W3-7 Private Sector Physics | Secteur privé Physique

(DCMMP) W3-8 Frontiers of Synchrotron Based Materials Physics | Frontières de la physique des matériaux basée sur le rayonnement synchrotron (DPMCM)

357 The Far-IR beamline: applications of long-wavelength synchrotron light at the CLS

Usually a scientist considers of synchrotron light in terms of short-wavelength hard UV or X-ray radiation delivered in a beam of very small diameter. However, the same beam also provides intense and well-collimated radiation of much longer wavelength (~5-300 µm), in the far-infrared spectral region. At the Far-IR beamline of the Canadian Light Source synchrotron we conduct experiments on the spectra of gas-phase molecules, which we can obtain with extremely high resolution and signal-to-noise ration on a reasonable time scale. Our data are valuable to astrophysicists who compare our terrestrial measurements to those obtained from atmospheres of remote bodies (stars, moons of planets, exoplanets), the interstellar medium, and other sources. We also conduct experiments on extremely small samples subjected to extreme pressures. I will discuss the capabilities of the beamline, and examples of experiments performed on it.

Speaker: Dennis Tokaryk (University of New Brunswick)

358 Soft x-ray absorption and scattering studies of quantum materials

Soft x-ray absorption and scattering at transition metal L2,3 edges has been an extremely prolific method for researchers over the past several decades. Our understanding of the multiplet-dominated lineshapes allows for detailed analyses of oxidation states and charge transfer effects, magnetism, and electronic effects of local site symmetry, for example. However, strongly covalent compounds with high oxidation states have always posed a problem for conventional models. I will present our recent work in developing more sophisticated approaches to tackle these difficult cases. I will focus on applications within correlated 3d transition metal oxides, including bulk materials and thin film heterostructures, and synchrotron techniques including absorption, scattering, and reflectivity. This improved modelling is relevant for fields including quantum materials, oxides for battery electrodes, metal-insulator transition materials, and more.

Speaker: Robert Green (University of Saskatchewan)

(DPP) W3-9 Plasma Physics and Technology | Physique et technologie des plasmas (DPP)

359 STOR-M tokamak research program—A four-decade long Journey

STOR-M tokamak design was conceived in early 1980s in the Plasma Physics Laboratory (PPL) at the University of Saskatchewan, and the first discharge was achieved in 1987. It is currently the only tokamak in Canada. STOR-M has accumulated more than 360000 discharges and remains active for the purpose of research and training. STOR-M has made many original contributions to tokamak confinement studies and to technology development. STOR-M pioneered alternating current (AC) tokamak operation mode which takes advantage of efficient current drive and ohmic heating. AC operation was later repeated in many other large tokamaks, such as JET and the HT-7 superconducting tokamak. STOR-M team was involved during the early stage of development of direct central fueling technology using compact torus (CT) injectors for magnetically confinement fusion reactors. CT injection triggered improved confinement (H-mode like) in STOR-M. PPL also initiated bursting repetitive CT operation at 10 Hz. Other significant contributions from STOR-M include turbulent heating by superimposing a sharp current pulse on the plateau of the plasma current, studies of improved confinement triggered by various techniques including electrode biasing, CT injection, resonant magnetic perturbations, and turbulent heating. Recently, PPL has also expanded the research areas to studies of (a) plasma-dust interaction by introducing spherical micro-tungsten dust into the STOR-M discharge and by evaluation of the dragging force on the dust in the rotating STOR-M plasma, (b) magnetohydrodynamic instability precursors leading to disruptions using internal magnetic probe arrays, and (c) damages of the first-wall material(tungsten) in tokamaks using intense energetic ion beam produced in a 2-kJ dense plasma focus device.

Speaker: Prof. Chijin Xiao (University of Saskatchewan)

Xiao-Abstract.docx

360 Interaction between ELM and ITB on EAST tokamak

The penetration of edge localized mode (ELM) into internal transport barrier (ITB) plasma has been studied on the EAST tokamak with flat central safety factor profile q(0) ~ 1 recently. The experiment indicates that when the ELM inward penetration radius reaches to the ITB foot region, a significant influence on the ITB plasma is manifested, leading to the shrinking or collapse of the ITB on the EAST tokamak. Observations suggest that the onset of large ELM penetration, which extremely reduces the pedestal temperature and density, can trigger the collapse of the ITB, by means with the off-axis sawtooth on EAST tokamak. The off-axis sawtooth events contribute to a further decrement in the core stored energy after a bigger ELM crashes in the pedestal region. The reversal surface of the off-axis sawtooth is situated around the ITB foot. The delay time between ELM penetration reached to ITB foot and the followed off-axis sawtooth collapse is about 2~3 ms. It is also found that the shrinking and expanding of ITB is related with the net heating power. Mechanism of ITB collapse from ELM penetration to the off-axis sawtooth triggered is not clear yet. Experiment results for understanding ELM penetration in ITB plasmas are summarized and discussed. This work has been supported by the National Key R&D Program of China (Contract No. 2022YFE03050003) and the National Nature Science Foundation of China (Grant Nos. 12175277). This work was supported by the RIAM joint usage/research project in 2024.

Speaker: Prof. Xiang Gao (Institute of Plasma Physics, Chinese Academy of Sciences)

ELM and ITB by Gao.docx

361 Final Announcements and Plenary Talk Announcement

Final Announcements DPP and Plenary Talk Announcement

Speaker: Stephan Reuter (Polytechnique Montreal)

Best Student Poster Competition Finals Judging (Closed to delegates) | Jugement des finales de la compétition d'affiches étudiantes (session fermée)

Best Student Poster Competition Judges Meeting | Réunion des juges du concours du meilleur poster étudiant(e)

DGEP Reception | Réception DEGP

Thursday 12 June

07:00 Congress Registration and Information (07h30-17h00) | Inscription au congrès et information (07h30-17h00)

CINP Board Meeting | Réunion du conseil d'administration du CINP

08:45 Plenary hall opens | Ouverture de la salle plénière

R-PLEN1 Plenary Session | Session plénière - Dennis Whyte, MIT

362 Accelerating commercial fusion energy with high magnetic fields and technology innovation

The advent of REBCO high-temperature superconductors at commercial scale has changed the development path for producing fusion energy with magnetic confinement.

The design and test of a large-bore B>20 tesla peak field superconducting magnet at MIT PSFC, in collaboration with Commonwealth Fusion Systems, realizes a doubling of the allowed B field compared to previous state of the art. This realizes extremely large gains in fusion performance fusion power density scales as B^4 and access to ignition as ~B^5 at fixed plasma physics.

These gains in turn allow for operation away from limits, yet in much smaller and less expensive devices. CFS is presently constructing the high-B tokamak SPARC outside Boston with MIT as its major scientific collaborator, with the goal of demonstrating high fusion energy gain and fusion power density that propels fusion into the commercial energy sector. In addition to describing SPARC, parallel key fusion technology development programs will be described.

Speaker: Dennis Whyte (Massachusetts Institute of Technology)

09:45 Health Break with Exhibitors | Pause santé avec les exposants

R-STUD-COMP CAP Best Student Oral Presentations Final Competition | Compétition finale de l'ACP pour les meilleures communications orales d'étudiantes

12:00 Break for Lunch (12h00-13h30) | Pause pour dîner (12h00-13h30)

CINP Annual General Meeting (with lunch) | Assemblée générale annuelle de l'ICPN (dîner inclus)

IPP Science Council Meeting | Réunion du Conseil scientifique de l'IPP

New Faculty Lunch with NSERC | New Faculty Lunch with NSERC

CINP + IPP Joint Session | Session conjointe CINP + IPP

(DASP) R1-1 Kathryn McWilliams Memorial Session I | Session commémorative Kathryn McWilliams I (DPAE)

(DCMMP) R1-2 Quantum and Strongly Correlated Materials | Matériaux quantiques et fortement corrélés (DPMCM)

363 Entanglement growth in the disordered Fermi Hubbard model

How isolated quantum systems reach thermal equilibrium is a long-standing question of continuing interest. The absence of equilibration in some systems is also well known, notably Anderson localization in noninteracting systems with quenched disorder. More recently, the term many-body localization has been applied to interacting systems in which equilibration is suppressed by disorder. While its persistence in the thermodynamic limit remains an open question, this effect is observed in experiments which are necessarily done in finite size systems and finite times. Most of the theoretical work in this area has focused on systems in which there is just one local degree of freedom—spin or charge. Meanwhile, systems with multiple coupled degrees of freedom are of interest, not least because most experimental studies of many-body localization use cold atoms described by the Hubbard model with two local degrees of freedom—spin and charge. Focusing on the case of the disordered Fermi Hubbard model, we ask How does disorder in charge influence localization in spin? How does entanglement grow with time? and What are the charge and spin contributions to this growth?

Speaker: Rachel Wortis

364 2PI strong coupling approach to out of equilibrium dynamics of the clean and disordered Bose Hubbard model

Out of equilibrium phenomena in the Bose-Hubbard model (BHM), such as the spreading of correlations, thermalization and many-body localization have attracted considerable interest in recent years. We have developed a two particle irreducible (2PI) strong coupling (2PISC) approach that allows us to access out of equilibrium phenomena in dimensions higher than one. We have investigated the spreading of correlations in one, two and three dimensions and find quantitative agreement with measurements of the speed of spreading of single-particle correlations in both the one- and two-dimensional BHM realized with ultracold atoms. We demonstrate that there can be large differences between the phase and group velocities for the spreading of correlations and explore how the anisotropy in the velocity varies across the phase diagram of the BHM. We have also applied the 2PISC approach to the disordered Bose-Hubbard model and obtained equations of motion for spatio-temporal correlations and explored their equilibrium solutions, including phase diagrams. We note that the disorder strengths where the emergence of non-ergodic dynamics was observed experimentally in the two dimensional disordered BHM [Choi et al., Science 352, 1547 (2016)] appear to correspond to the Mott insulator - Bose glass phase boundary. Most recently we have used machine learning methods to obtain quantitative improvements to our calculations of single particle correlations. Our results establish the 2PISC approach as a powerful tool to study out-of-equilibrium dynamics in the BHM in dimensions greater than one.

Speaker: Dr Malcolm Kennett (Simon Fraser University)

365 Properties of Holstein polarons at finite temperature

We generalize the Momentum Average (MA) approximation to compute the finite temperature spectral functions of the Holstein polaron in an one-dimensional system. We validate our MA results in 1D against available numerical data from the density matrix renormalization group (DMRG) method and the finite-temperature Lanczos method, establishing the accuracy of the MA results which are obtained at a substantially lower computational cost. We use MA to to characterize the temperature range over which a coherent quasiparticle (the polaron) exists and we study the evolution with temperature of its effective mass and lifetime.

Speaker: Jeet Shannigrahi (University of British Columbia, Vancouver)

366 Towards an ab initio theory of high-temperature superconductors: a study of multilayer cuprates

A new quantum framework reveals how chemistry and crystal structure govern high-temperature superconductivity, explaining behaviors seen in multilayer cuprates and guiding the search for room-temperature superconductors.

While low-temperature superconductivity is well understood, the mechanisms behind superconductivity at higher temperature remain elusive. In this work, we propose a quantum mechanical framework aimed at identifying the key chemical elements and crystal structures needed to design new materials that superconduct at or near room temperature. The framework is based on Density Functional Theory plus Cluster Dynamical Mean-Field Theory.

To demonstrate our approach, we apply it to two families of copper-oxide superconductors known as multilayer cuprates. These materials hold the record for the highest superconducting temperatures at ambient pressure. Using our model, we explain why superconducting properties depend on the number of superconducting layers, why mercury-based cuprates outperform calcium-based ones, and how magnetism, electronic structure, and charge distribution influence superconductivity. Our predictions align closely with experimental observations, showing the strength of this method in capturing complex material behaviors.

This work lays the foundation for a comprehensive, first-principles understanding of high-temperature superconductors. Looking ahead, we aim to extend our method to large-scale computational searches and apply it to other classes of materials, such as nickelates and pnictides. By doing so, we move closer to the long-standing goal of designing a superconductor that operates at room temperature.

Paper accepted in Phys. Rev. X

Speaker: André-Marie Tremblay (Université de Sherbrooke)

(DPE) R1-3 Physics Education II | l’enseignement de la physique II (DEP)

367 Bringing Makerspace Pedagogy Into The Studio Physics Classroom: A Case Study at Fraser International College

As part of the redesign of the calculus-based mechanics course PHYS 140 – Studio Physics - Mechanics and Modern Physics offered both at Simon Fraser University (SFU) and Fraser International College, a collaborative final project (CFP) was introduced into the course. At the group level, students are responsible for designing, building, and testing a project of their choosing. At the class level, the groups bring their projects together to be assembled in the form of a Rube Goldberg machine. The CFP is designed for students work together within their groups, but also to collaborate with members of other groups on matters of theme selection, project coordination, and peer review. Students are encouraged to bring their creativity, curiosity, and individual strengths to their work, provided that they engage critically with the course content throughout their project.
In the building phase, students are introduced to the makerspace at the SFU Library, which provides tools such as 3D printers and laser cutters. These tools allow students to bring their ideas to life, which in turn presents an opportunity for them to explore the affordances and limitations of the models studied in class through their creations. In this talk, I will review how students use the makerspace to facilitate construction of the final project and discuss how the principles of makerspaces - projects, peers, passion, and play – complement the student-centred approach of the studio physics curriculum. I will outline how this approach reveals new opportunities for hands-on learning and design-based projects within the studio physics context. Lastly, I will highlight some of the students’ creations and share their personal experiences and reflections on their projects.

Speaker: Peter Smith (Fraser International College)

368 Transitions to University Physics: Observations About Students and Their Needs

This talk will focus on what students often experience in high school physics programs, and the pedagogy that could support student interest in, and continuation with, a physics education in university. This will take no more than 30 minutes including time for discussion and questions. The speaker, Murray Guest, is the 2021 Award For Excellence in Teaching High School in the Prairies-Northwest Territories Region.

Speaker: Murray Guest (Saskatoon Public Schools)

(DPMB) R1-4 | (DPMB): Accessible Imaging, Adaptive Care: Innovations in Women’s Cancer Treatment

369 Advancing Image-Guided Gynecologic Brachytherapy: Enabling Adaptive Treatment with Ultrasound Technologies

Despite evidence that internal radiation therapy (brachytherapy) used in gynecologic cancer treatment is integral to successful therapy, use of these techniques has been declining and access to advanced imaging to guide adaptive therapy is limited. The decline in popularity is in part owing to the complexity of the procedure, requiring aids to make accessible imaging available and interpretable, as well as low-cost yet effective training tools to improve uptake. This talk will focus on the creation of tools to aid radiation oncology and medical physics teams to adaptively assess treatment quality intraoperatively and provide high quality therapy, particularly in resource-constrained settings. The presentation will include an overview of novel 3D ultrasound imaging devices that have been recently translated into clinical trials for intraoperative feedback during gynecologic brachytherapy procedures and automated detection tools to aid in the interpretation of these images. I will also discuss opportunities to integrate multi-modality imaging with sensing and tracking technologies intraoperatively and into training initiatives, as well as opportunities to develop advanced image processing techniques with state-of-the-art deep learning methods to generate automated tools that facilitate understanding of the images available for image-guidance and image-based planning.

Speaker: Jessica Rodgers (Dept. of Physics and Astronomy, University of Manitoba)

370 Progress in Developing a Portable Microwave Breast Cancer Sensing System for Resource-Limited Settings

Breast cancer remains a leading cause of cancer-related deaths worldwide, with mortality disproportionately affecting resource-limited regions due in part to limited access to effective screening tools. This presentation will cover our decades-long design, development, and evaluation of microwave sensing/imaging (MWI) systems, with the goal of developing an affordable portable medical device for breast cancer detection tailored for use in resource-limited settings. The system leverages advancements in system design, physics-informed image reconstruction, machine learning and low-cost hardware to offer a safe, efficient, and accessible alternative for breast cancer detection. Preclinical testing on MRI-based tissue-mimicking phantoms demonstrates promising diagnostic accuracy, stability, and suitability for use in diverse environments. These findings underscore the potential of MWI to transform early breast cancer detection strategies and reduce global health disparities.

Speaker: Stephen Pistorius (Physics and Astronomy, University of Manitoba)

(DTP) R1-4 Dark Matter and Cosmology | Matière noire et cosmologie (DPT)

371 Title: The (Really) Small Scale Structure of Dark Matter

The statistical properties of dark matter (DM) on the largest scales in the universe are well described by the standard cosmological model. In contrast, comparatively little is known about the DM distribution within galaxies. I will discuss how early universe cosmological evolution and DM microphysics can result in enhanced structure, i.e. clumpiness, on sub-galactic scales. Using the examples of vector DM produced during inflation and a universe with a period of pre-nucleosynthesis matter domination, I will show how we can relate the microphysical parameters in these models (such as particle masses and lifetimes) to the late-time properties of gravitationally-bound DM clumps called microhalos. I will then describe a promising technique for detecting microhalos using observations of highly-magnified extragalactic stars. Such observations can give us insight into the pre-nucleosynthesis universe, and the particle nature and origin of DM.

Speaker: Nikita Blinov (York University)

372 No static black hole horizons in the expanding universe

It is shown (in spherical symmetry) that an exactly static black hole horizon cannot exist in an expanding universe. If you try to make it static in any dynamical ``background'', it becomes a naked spacetime singularity. This fact is demonstrated by the incompleteness of radial null and timelike geodesics, by the divergence of curvature invariants, the energy-momentum of a test scalar field, and by inconsistencies with Hawking radiation. Black holes are somehow coupled to the cosmic expansion, which was suggested independently as the growth mechanism for supermassive black holes in galaxies, with tentative observational evidence reported in 2023.
[Based on V.F. & M. Rinaldi 2024, Phys. Rev D 110, 063553 (arXiv:2407.14549)]

Speaker: Valerio Faraoni

373 A Novel Vacuum Cosmological Model

A novel vacuum (Riemann-flat) exact solution to the cosmological General Relativistic field equations has the feature that it is independent of the form of the cosmic scale factor. Spatial sections of this model solution are negatively curved and thus can mimic the acceleration of comoving observers attributed to dark energy. We perform a fit to the Union2.1 supernovae data set, yielding ranges of values for a cosmological distance scale, $D = 1800_{-135}^{+150}$ Mpc and the Hubble-Lemaitre constant, $H_{0} = 65_{-10}^{+12}$ km/s/Mpc, respectively.

Speaker: Patrick Kelly (University of Mary)

15:00 Health Break with Exhibitors | Pause santé avec les exposants

Student Awards Ceremony | Cérémonie de reconnaissance d'étudiant(e)s

R-PLEN2 Brockhouse Medalist Plenary Session | Session plénière - Peter Grutter, McGill U.

374 Quantum dots, dopants, defects - measuring properties using atomic force microscopy

Understanding and pushing ultimate limits is one of the joys of Physics. Atomic Force Microscopy (AFM) is a well-established technique that can image individual atoms and thus determine the atomic structure of even insulating surfaces and molecules in almost any environment. To gain fundamental insight into ‘how stuff works’ and to apply these insights to purposeful engineering one needs to go beyond structure and measure properties.

I will introduce how the measurement of electrostatic forces allows properties to be measured and will illustrate the resulting capabilities with a few examples. Specifically, I will discuss the measurement of single electron charging energies of quantum dots, individual dopants in silicon, atomic defects at the SiOx-Si interface and the observation of random telegraph noise of a single trap. When AFM is combined with a fast pulsed laser, we demonstrated a temporal resolution of 100fs (limited only by the laser pulse length) by measuring the light induced non-linear polarization in the sample. This opens the exciting possibility of correlating the atomic scale structural and electronic properties down to a single defect in many materials on a 10fs time scale.

Speaker: Peter Grutter (Dep. of Physics)

R-PLEN3 Vogt Medalist Plenary Session | Session plénière - Mark Boulay, Carleton U.

(DTP) R2-1 Particle and Mathematical Physics | Physique des particules et physique mathématique (DPT)

375 Heavy-Light Diquark Mass Splitting from QCD Sum-Rules and Diagrammatic Renormalization Methods

QCD Laplace sum-rules are an important tool to extract information about bound states of quarks from perturbative QCD with non-perturbative effects of QCD condensates. Applying the QCD Laplace sum-rules to strange and non-strange heavy-light diquarks, I compare their masses. Diquark correlation functions are renormalized using the diagrammatic renormalization method. It is found that the strange quark condensate parameter $\kappa = \langle \bar{s}s\rangle/\langle\bar{n}n\rangle$ plays an important role in determining the heavy-strange $[Qs]$ and heavy-non-strange $[Qn]$ diquark mass splitting.

Speaker: Thamirys de Oliveira (University of Saskatchewan)

376 Theory for electron-phonon systems at high levels of Joule heating: Spontaneous symmetry breaking with possible applications to chemical systems.

Recent work on dissipative electron-phonon type systems will be reviewed. A Boltzmann transport equation was formulated which accounts for second order collisions with an electron-phonon vertex and a three-phonon vertex. This approach reveals the existence of two forces perpendicular to the primary direction of electrical current, equally and oppositely acting on electrons and phonons. Solutions for stationary states confirm that charge and thermal energy become separated. The phonon force leads to a modified Guyer-Krumhansl equation. If enough power is dissipated, the electron and phonon dynamics can experience spontaneous symmetry breaking.

More recently, the same approach was taken for chemical reaction-diffusion systems.
Again, scattering processes up to second order are taken into account and again, two forces emerge when a spatial gradient exists, one force on reactants and products, the other force on phonons. The forces are equal and opposite and have the tendency for separation of the phonons away from the reactants and products. These forces are capable of creating the types of instabilities that can lead to the formation of Turing patterns. The existence of these forces allows for exergonic conversion where not all of the released energy from reactions and diffusion becomes heat. In the realm of high-energy explosions, calculations show that reactants and products can be accelerated laterally to the direction of a TNT reaction front up to speeds near 1000 m/s. This acceleration is in opposition to diffusion and represents active transport. Calculations also show that active transport observed in biological systems such as bacteria, mitochondria, and chloroplasts may be explained by this second-order transport theory. Using reasonable values for key parameters, calculations show that up to one-third of the available chemical energy can be converted toward pumping protons uphill to a potential of 50 mV. This gives a physical understanding for Mitchell's general chemiosmotic mechanism which is an important concept in biochemistry.

S.N. Patitsas, Phys. Rev. E \textbf{108}, 024201 (2023)

Speaker: Steve Patitsas (University of Lethbridge)

377 Superselection in gauge theory

In describing physical systems, we often assume that the system can be fully understood in isolation from the rest of the universe. This assumption is generally valid and leads to physical theories enjoying certain ‘locality’ properties which play a foundational role in much of quantum field theory. However, there are fundamental scenarios where locality is subtly breached already classically. The most significant such breaches occur in electrodynamics, where Gauss’s law allows one to measure the total charge of a system from arbitrarily far away, and general relativity, where the Hamiltonian constraint ultimately suggests a `holographic principle'. In this talk I will discuss recent efforts to investigate the consequences of non locality in gauge theories through the study of the geometry of their phase space in the presence of spacetime boundaries, understood as mathematical models of the idealized interface between the system of interest and the rest of the universe. This will lead us to the concept of (classical) superselection sectors, whose physical meaning is clarified by a gluing theorem. It will also shed new light on the much-studied topic of 'new asymptotic symmetries' of gauge theories by relating electromagnetic memory and superselection. Finally, I will briefly comment on the obstacles one must face in generalizing this results to gravity. Based on works with Gomes and Schiavina. -- References. The general framework: 2207.00568 Null Yang-Mills: 2303.03531 Gluing: 1910.04222 A pedagogical introduction: 2104.10182 Dressings and reference frames: 1808.02074, 2010.15894, 1608.08226

Speaker: Aldo Riello (Perimeter Institute / University of Waterloo)

378 Theoretical analysis of non-linear dynamics response of a bridge pier under two-phase turbulent flow

Despite the development in Engineering, the structure such as bridge continue to collapse due to fluid loads effects. Their combination on a bridge pier can also induced catastrophic damages. Less attention in literature has been given to bridge pier dynamics under transversal flow. This work describes the dynamic vibration, including theoretical non-linear dynamics analysis, of a bridge pier under two-phase turbulent fluid flow. An overview of the description of a bridge pier and the different types of phase flow that can induce vibration in such a structure is presented. The external excitations due to two-phase flow are modelled first as two-frequency excitations, and secondly, for two-phase turbulent flow, the turbulence in the fluid load expression is given by independent unit Weiner processes. In both cases, the physical system is mathematically modelled as a non-linear partial differential equation. The mathematical framework, including Galerkin's method and some integrations taking good consideration of the space occupation of each phase of fluid flow along the beam, is developed to obtain the discrete general equation. To make the model more meaningful and practical, constant and parametric axial loads representing the bridge deck, taking into account their different states, are used in the modelling system. Using adequate analytical methods and numerical simulations, the non-linear dynamic behaviour of the bridge pier under turbulent two-phase flow or taking flows as frequency excitations is studied. This leads to the evaluation of non-linear dynamic responses through amplitude responses, time domain response diagrams, and phase plan diagrams. The results show good agreement between the analytical and numerical solutions. Moreover, with the obtained results, we show that the increase in wind velocity has a great impact on the heightening of the amplitude response of the system, unlike the rise in water velocity. Furthermore, we demonstrate that for certain values of fluid velocity and height of water, a bridge pier subjected to two-phase fluid flow is more stable than when it is subjected to one fluid flow. Thus, we come to the conclusion that the inertia effects of water contribute to the stabilization of bridge piers in the case of two-phase turbulent flow excitations in the chosen proportions.

Keywords: Bridge pier, Euler-Bernoulli beam theory, two-phase flow excitation, turbulent fluid flow, amplitude of vibration, non-linear dynamic response, water inertia effects, structural stability.

Speaker: Dr Loïc NGOU ZEUFO (Cégep Beauce-Appalaches)

Abstract Ngou -CAP Congress 2025.pdf

(DASP) R2-2 Kathryn McWilliams Memorial Session II | Session commémorative Kathryn McWilliams II (DPAE)

Convener: Daniel Billett (University of Saskatchewan)

(PPD) R2-3 Searches for dark matter III | Recherche de la matière noire III (PPD)

379 Particle Physics On the Cosmic Frontier: Higgs Inflation Revisited

Cosmic Inflation provides a window into the highest energy scales realized in the history of our universe. Higgs Inflation, wherein the Standard Model Higgs or a variant is identified as the inflaton, provides a minimal framework for incorporating cosmic inflation into the Standard Model. In this talk I will revisit particle production in Higgs Inflation, and present new idiosyncratic aspects which distinguish it from other inflation models, with implications for the production of dark matter, the baryon asymmetry of the universe, and particle physics experiments.

Speaker: Evan McDonough

380 The global search for weakly-interacting dark matter using liquid argon

Experiments with liquid argon are being developed for direct detection of dark matter into the neutrino fog, for mass scales from 0.5 GeV/c$^2$ to >1000 TeV/c$^2$. This builds on the work of the DEAP-3600 detector, currently running at SNOLAB, as well as on the DarkSide-20k detector, under assembly at the LNGS underground laboratory in Italy. Recent results from the analysis of DEAP-3600 data will be discussed, as well as the physics goals of DarkSide-20k, highlighting important Canadian contributions to the data acquisition, construction of the time projection chamber, deployment of surface coatings, construction of the calibration systems, and material assay and quality control for radiopurity.

Steps taken beyond DarkSide-20k are centred around the development of pixelated digital silicon photodetectors, which will be deployed in the ~1m scale single-phase prototype named ARGOlite to be deployed at SNOLAB in the Cube Hall, replacing DEAP-3600. These photon detectors will also be deployed in a time projection chamber (TPC) prototype to be located in Naples, and will further contribute to the development of the ALARM2 liquid argon detector for security applications at Canadian Nuclear Laboratories.

Physics and engineering design are underway for ARGO, a 300-tonne fiducial mass detector for deployment at SNOLAB. ARGO will require 250 m$^2$ of digital photon detectors as well as a real-time intelligent data acquisition system. In addition, the cryostat for ARGOlite is being designed such that it could hold the DarkSide-LowMass detector. Building on the success of DarkSide-50, DarkSide-LowMass is a proposed tonne-scale TPC optimized as a low-threshold electron-counting measurement using only the ionization channel to have sensitivity to low-mass dark matter.

Speaker: Prof. Simon Viel (Carleton University)

381 Latest Results from the SuperCDMS-HVeV Program

The SuperCDMS-HVeV (High-Voltage with eV resolution) program is an R&D project focused on developing detectors with low energy resolution to search for low-mass dark matter (≲ 1 GeV/c2), study charge-transport in cryogenically cooled crystals, and probe unclassified backgrounds at low energy. The program utilizes gram-scale silicon detectors instrumented with TES (transition-edge sensor)-based phonon sensors. A voltage bias can be applied to the crystal to amplify phonon signals from ionizing interactions via the Neganov-Trofimov-Luke effect. HVeV detectors have recently achieved sub-eV baseline energy resolutions and demonstrated competitive sensitivities to electron-recoil dark matter at masses below 1 MeV.This talk will provide an overview of the latest developments in the HVeV program. This includes the results from a dark matter search conducted at the NEXUS underground facility which featured a redesigned detector housing aimed at reducing backgrounds from dielectric materials used in previous designs. I will present preliminary results from the most recent data-taking campaign at SNOLAB, with a new iteration of these detectors. Finally, I will preview the next generation of HVeV detectors which seek to improve upon the original design to achieve lower thresholds and mitigate backgrounds.

Speaker: Ziqing Hong (University of Toronto)

382 First operation and assessment of SuperCDMS SNOLAB detectors at the CUTE facility

The next-generation SuperCDMS experiment at the SNOLAB underground laboratory is designed to probe dark matter particles with masses below 10 GeV/c² using highly sensitive silicon and germanium cryogenic detectors. Before the experiment undergoes commissioning, it is essential to test these detectors in an environment with similar conditions to assess their performance, optimize operational parameters, validate calibration techniques, and troubleshoot technical issues. The Cryogenic Underground TEst facility (CUTE) at SNOLAB is a dedicated low-background facility designed for this purpose. This talk will cover aspects of the first testing and characterization of SuperCDMS High Voltage (HV) detectors at CUTE, highlighting initial calibration efforts and key performance results.

Speaker: Ariel Zuniga Reyes (University of Toronto)

383 Simulation of radiation impact on qubits operated deep underground at SNOLAB

Quantum technologies based on solid-state devices attract a growing interest in both academic and industrial research, which is why understanding their performance limitations and finding effective mitigation strategies is a key priority. Even though quantum coherence times of superconducting circuits have increased from nanoseconds to tens and hundreds of microseconds, further improvements are needed to reduce the hardware overhead of conventional quantum error correction schemes.

On a fundamental level, reaching this goal requires reducing the density of broken Cooper pairs (so-called quasiparticles) in the circuitry. One hypothesized source of non-equilibrium quasiparticles are interactions of ionizing radiation with the substrate of solid-state devices arising from environmental radioactivity and cosmic rays. A new collaboration between researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo, the Sudbury Neutrino Observatory Laboratory (SNOLAB), Ontario, and Chalmers University of Technology in Sweden has been formed to investigate the impact of ionizing radiation and cosmic rays on quantum technologies. The goal is to perform an advanced characterization of superconducting transmon qubits by operating them deep underground in SNOLAB's Cryogenic Underground TEst facility (CUTE) -- coined the QUTEbits project.

This talk will briefly introduce the QUTEbits project at SNOLAB and summarize simulation studies performed with GEANT4 to characterize the expected backgrounds at CUTE. Additionally, first results of using the G4CMP condensed matter physics extension to GEANT4 will be shown to help evaluate the impact of radiation on qubit decoherence.

Speaker: Stefan Zatschler (Laurentian University, SNOLAB, University of Toronto)

(DCMMP) R2-4 Superconductivity and Magnetism | Supraconductivité et magnétisme (DPMCM)

384 Exotic pairing in multiband superconductors

In the standard BCS theory of superconductivity, the Cooper pairs are formed by electrons from the same band. However, pairing of electrons from different bands may play an important role in many superconducting materials of current interest. Including interband pairing alongside the usual intraband one leads to qualitative changes in the nodal structure: energy gap nodes can (dis)appear, merge, and leave high-symmetry locations in the Brillouin zone. The Andreev boundary modes change qualitatively with increasing the interband pairing, e.g., flat zero-energy boundary states characteristic of a d-wave pairing gap out and transition to helical edge states. Depending on the symmetries of the bands involved in the Cooper pairing, some unusual gap features become possible, such as odd-parity singlet and even-parity triplet gaps. Also, a variety of time-reversal symmetry breaking superconducting states are stabilized by interband pairing.

Speaker: Prof. Kirill Samokhin (Brock)

385 Gapless superconductivity and its real-space topology in quasicrystals

There are increasing interests in topological phenomena in quasicrystals (QCs), which possess long-range order without periodicity. Superconductivity has been discovered experimentally in QCs [1], and some theoretical works have shown that topological superconductivity can emerge in two-dimensional QCs such as Ammann-Beenker (AB) QCs [2]. However, there is no fundamental difference in the nature of topological superconductivity compared with that in periodic systems, and no new topological phenomenon unique to QCs has been found so far.

Some QCs including AB QCs exhibit a flat band of highly degenerate confined states at zero kinetic energy, due to local geometry of their quasicrystalline lattice. In this work, we show the stable occurrence of gapless superconductivity in AB QCs under magnetic field at or near half filling, where the chemical potential lies in or near the highly degenerate flat band. Gapless superconductivity originates in broken translational symmetry and confined states, and therefore it is unique to QCs. When Rashba spin-orbit coupling is present, this gapless superconducting phase can be topologically nontrivial, with edge states at near-zero energy among numerous bulk states. Even though this phase is gapless, its topological nature can be signified by a nonzero pseudospectrum invariant in real space given by a spectral localizer [3].

[1] K. Kamiya et al., Nat. Commun. 9, 154 (2018); Y. Tokumoto et al., Nat. Commun. 15, 1529 (2024); T. Terashima et al., npj Quantum Mater. 9, 56 (2024).
[2] M. Hori, T. Sugimoto, T. Tohyama, and K. Tanaka, Phys. Rev. B 110, 144512 (2024).
[3] K. Saito, M. Hori, R. Okugawa, K. Tanaka, and T. Tohyama, arXiv:2410.01236.

Speaker: Prof. K. Tanaka (University of Saskatchewan)

386 Noncollinear magnetic random access memory

Semiconductor random access memory (RAM) is a fast, volatile memory used by computers to store data. In the early 2000s, it was demonstrated that magnetic moments can be manipulated using electric currents, enabling the development of magnetic RAM (MRAM) that matches the speed of semiconductor RAM while also being non-volatile—that is, capable of retaining data even when power is turned off. Although MRAM has been realized, it is currently used only in specialized applications. One of the main barriers to broader adoption is the collinear alignment of magnetic layers in state-of-the-art designs, which thus rely on thermal agitation to induce the noncollinear alignment necessary for current-driven magnetization switching. Recently, we have identified novel spacer layers that can be inserted between magnetic layers to precisely control the relative orientation of their magnetic moments, enabling the required noncollinear alignment for efficient current-induced switching. In this talk, I will present the composition and fabrication of the spacer layers used to establish noncollinear coupling as well as a theoretical framework that we have developed to explain how these layers control the angle between adjacent magnetic moments. Additionally, I will present results from micromagnetic simulations, through which we explored MRAM designs that incorporate noncollinear coupling. These demonstrate switching performance that is twice as fast as and more energy-efficient than the state-of-the-art.

Speaker: Erol Girt (Simon Fraser University)

CAP conference 2025 invited talk - abstract.pdf

387 Characterizing qubit decoherence deep underground at SNOLAB

Although superconducting qubits have seen improvements in coherence times over the last decades, their performance remains orders of magnitude below that needed for a fully realizable quantum computer. A major limitation is driven by large populations of non-equilibrium quasiparticles in the qubits which can induce decoherence. These quasiparticles may originate when ionizing radiation, either from cosmic rays or the environment, break Cooper pairs in the superconducting circuitry. The Cryogenic Underground TEst Facility (CUTE) at SNOLAB, with 2 km of rock overburden, provides an ideal venue for testing these hypotheses. The QUTEbits Collaboration is a new collaboration between Chalmers University of Technology, the Institute for Quantum Computing at the University of Waterloo, and SNOLAB with the goal of studying the origin of this major decoherence mechanism. By operating the same set of transmon qubits both in surface facilities and underground at CUTE, their performance in different radiation environments can be compared. This talk will describe the QUTEbits project and summarize the results obtained so far.

Speaker: Tyler Reynolds (University of Toronto)

(DPE) R2-5 Physics Education III | l’enseignement de la physique III (DEP)

388 Comparison of Competence-Based Assessment and Traditional Assessment for Lab Activities in Physics for Engineers.

The Physics and Engineering Physics department offers Electromagnetism and Waves as part of the “Re-Engineered” First year program. The First-year Engineering Team has introduced Competency-Based Assessment (CBA) to create a more constructive and supportive learning environment. An exploration into the application of CBA to the Physics labs was conducted to compare learning and grading outcomes for First-year Engineering Students. The CBA approach aims to make learning outcomes clear, provide feedback and the opportunity for correction and growth in the learning process. The teaching assistants were trained to provide coaching and feedback during lab activities, to provide feedback in real-time. Following the activity, students submitted their work online for assessment. The grading was categorized to target specific lab-based skill: record keeping, experiment procedure, data collection, analysis, conclusions and sources of error. Grading was completed using a traditional points reduction scheme, and student growth was evaluated using an algorithm: if the student grade improved in a category, the new grade was retained; if the grade went down, the new grade was calculated as a 60/40 weighted average of the first and second activities. The data collected allows for a direct comparison of the traditional grading scheme with the CBA approach.

Speaker: Sarah Purdy (University of Saskatchewan)

389 Supporting Early Career Researchers at TRIUMF: A Review of the Mentorship Pilot Program

TRIUMF, Canada’s Particle Accelerator Centre, employs or hosts an average of more than 200 postdoctoral researchers, graduate students, and undergraduate students each year. To better support these early career researchers, a mentorship program was developed and piloted to specifically target this group. The program, which ran over a six-month period from May to October of 2024, featured two mentorship streams: a “buddy” stream, and an “academic” stream. The “buddy” stream aimed to have mentors provide guidance to their mentees focused on navigating the progression-based hurdles that accompany joining a new institution, while the “academic” stream mentors provided mentorship focused on career growth. Program evaluation included an early check-in survey and an end-of-program survey. In this talk, we will overview this new TRIUMF mentorship program, present results from the surveys, and discuss strategies for program enhancement and future success.

Speakers: Dr Benjamin Davis-Purcell (TRIUMF), Gabby Gelinas (UBC/TRIUMF)

390 Challenges and Opportunities in Graduate Physics Education

In a workshop format, we will examine the rapid changes over the past decade that have led to challenges to offering graduate physics programs. Potential opportunities will also be discussed.

Speaker: Chitra Rangan

(DNP) R2-6 Fundamental symmetries | Symétries fondamentales (DPN)

391 The origin of high-energy astrophysical neutrinos

IceCube, a high-energy neutrino observatory with a cubic kilometre active volume, has discovered astrophysical neutrinos with energies higher than a few tens of TeV. While the sources of these neutrinos are still unclear, their isotropic distribution supports that the majority of these neutrinos have an extragalactic origin. IceCube has conducted searches for the sources of this neutrino flux, which resulted in 3-sigma detections of neutrino emission from two extragalactic objects, TXS 0506+056 and NGC 1086, and a 4-sigma detection of neutrino emission from the Galactic plane. In this talk, I will review the high-energy neutrino measurements up to the present and discuss the potential counterparts for this emission.

Speaker: Nahee Park

392 MOLLER Experiment

The MOLLER experiment is a >$40M USD experiment expected to begin to run in late 2026. This experiment has a large Canadian contribution, to both the spectrometer and detector systems. The experiment utilizes parity-violation in the weak interaction to measure the asymmetry between longitudinally polarized electrons in the positive and negative helicity states. The electrons scatter from electrons in liquid hydrogen, are collimated and bent through the spectrometer system to the main detector array. There are 224 integrating quartz detectors in the array. In addition there are a set of tracking detectors to study backgrounds and determine the acceptance. In fact, the whole accelerator is part of the experiment, with beam position and charge monitors throughout the beamline serving to study helicity-correlated backgrounds. In this talk I will describe the goals of the MOLLER experiment and its design and provide a status, in particular of the spectrometer and detector systems.

Speaker: Juliette Mammei

393 Deep Exclusive Kaon Electroproduction at Jefferson Lab

One of the long standing questions in the standard model of particle physics is the origin of the nucleon spin and the charge and density distributions inside the nucleon. In the theory of the strong interaction, the structure of the nucleon is described by form factors which can be accessed through hard exclusive meson production. The main focus of this study is to measure the form factor of one of the lightest mesons and simplest bound state of a quark and an antiquark, the kaon. The kaon form factor is measured indirectly from the scattering of a high-intensity electron beam on a proton target producing a kaon along with the Λ and Σ baryons. The data analyzed here were taken at 3.8 GeV and 4.9 GeV beam energies at Jefferson Lab using the high precision Hall C spectrometers. We will present the status and plans to measure the kaon form factor at the Hall C experiment in Jefferson Lab, using data from production run in fall of 2018.

Speaker: Abdennacer Hamdi (University of Regina)

394 Glueballs in QCD sum rules

Glueballs are colorless bound states of gluons as they have self-couplings. The existence of glueballs are very distinctive predictions of QCD. In this talk, I will briefly review recent experimental and theoretical progresses on the researches of glueballs. Especially, I will introduce the latest QCD sum rule calculations of the mass spectroscopy for the two-gluon and three-gluon glueballs.

Speaker: Prof. Wei Chen

395 Microwave spectroscopy of antihydrogen in the ALPHA experiment

The imbalance between matter and antimatter in the universe remains one of the biggest unanswered questions in physics. As the simplest purely antimatter atomic system, antihydrogen serves as an ideal platform for testing the fundamental symmetry between matter and antimatter (Charge-Parity-Time symmetry). Precise measurements of antihydrogen’s transition frequencies, in direct comparison with their well-established hydrogen counterparts, provide a stringent test of CPT symmetry within the atomic sector. For example, microwave spectroscopy of the ground-state hyperfine splitting presents a promising avenue for exploration. In hydrogen, this transition has been measured with a precision of $1\times10^{-12}$ and an absolute accuracy of 2 mHz, compared to 10 Hz for the 1S–2S transition potentially providing a probe for different physics.

The ALPHA collaboration at CERN has been leading the way in testing fundamental physics with magnetically trapped antihydrogen. Notable recent advances include high-precision spectroscopy of the 1S–2S transition, fine structure measurements, the first demonstration of laser cooling of antihydrogen, and the groundbreaking first observation of antihydrogen’s gravitational free fall. Additionally, improvements in magnetic field control and significantly enhanced antihydrogen trapping rates, achieved through Be+ ion-assisted production, have opened new possibilities for microwave spectroscopy. In this talk, I will present ALPHA’s latest microwave spectroscopy results and discuss prospects for achieving even higher precision measurements in the near future.

Speaker: Timothy Friesen (University of Calgary)

(DPMB) R2-7 | (DPMB): Bright Beams, Broad Impact: Synchrotron Innovations in Medicine and Food

396 The Biomedical Beamlines at the Canadian Light Source – A Bit of History and Diffractive X-Ray Optics Development for Biomedical Application

The BioMedical Imaging and Therapy (BMIT) facility is comprised of two beamlines at the Canadian Light Source – one sourced by a superconducting wiggler (BMIT-ID) and a second with a bend magnet source (BMIT-BM). A bit of the history of the beamlines, capabilities and applications will be given. The bend magnet beamline, BMIT-BM, allows both filtered white beam access as well as monochromatic beam prepared by a double crystal monochromator. Access to the filtered white beam provides an opportunity to develop various x-ray optics using x-ray diffraction akin to an “x-ray wind tunnel”. The diffracting elements are typically bent silicon wafers in the Laue or transmission geometry. Some of those optical developments will be presented along with principles of operation and applications including contrast element imaging, element speciation imaging, wide energy range imaging, vertical beam expansion and horizontal beam compression. The “beam expander”, a two-bent-crystal device similar to a Galilean optical expander, can provide expansions up to a factor of 10 while mostly preserving the spatial coherence that enables in-line phase contrast imaging.

Speaker: Dean Chapman (University of Saskatchewan)

397 Photons for Food and Medicine

Since the discovery of X-rays and radioactivity at the end of the 19th century, nuclear radiations, especially photons of a few hundred keV to MeV energies have found applications in various aspects of human life, such as food irradiation, medical diagnostics and therapy. However, there is still room for further research and developments to optimize the technologies for maximum benefits.
We have been involved in studies of food irradiation with a few hundred keV X-rays rather than multi MeV electron/photon beams as the ultimate purpose is to induce atomic/molecular transformations rather than nuclear transmutations.
We have also been involved in exploring the possibility to produce medical isotopes at research reactors such as now defunct Saskatchewan Research Council SlowPOKE reactor.
As medical imaging using PET and SPECT technologies require elaborate computer algorithms in which a single event carries very little information about the tumor location, we attempt non-collinear cascade gamma coincidence technique as a marriage of PET and SPECT. Unlike other works to replace PET technologies, our method allows to retrofit the existing PET machines with our modality.
My talk will give a brief overview of our motivations, our methods and tools we employed so far and the current status of our works.

Speaker: Chary Rangacharyulu (Dept. of Physics and Engineering Physics, University of Saskatchewan)

18:00 Break Before Banquet | Pause avant le banquet

CAP Banquet + Fellows Recognition Dinner - Limited seating. Tickets will not be sold at the door | Banquet et reconnaissance des Fellows de l'ACP - Sièges limités; aucun billet vendu à l'entrée

Friday 13 June

SNOLAB Townhall Meeting | Réunion publique SNOLAB

CINP Townhall Meeting | Réunion publique du CINP

(PPD) F1-1 Particle physics at colliders II and muon g-2 | Physique des particules aux collisionneurs II et muon g-2 (PPD)

398 High Energy Physics at Low(er) Energies: Precision Measurements in Top Quark Physics at $\sqrt{s}$ = 5.02 TeV

Meet the top quark, the heavyweight champion of the subatomic world, tipping the scales at a mass comparable to a single tungsten atom. Unlike its lighter counterparts, this elusive particle has a flair for the dramatic by boasting the shortest lifespan of all quarks and the unique ability to be measured as a "free" quark, for a fleeting moment, before decaying. With the discovery of the Higgs boson through proton-proton collisions at the Large Hadron Collider (LHC) in 2012, and no sign of any physics beyond the Standard Model (SM), measurements of the top quark provide an alternate approach to understanding and testing the SM. This talk will present two measurements of the top quark at a centre-of-mass energy of 5.02 TeV, using 257 $\text{pb}^{-1}$ of proton-proton collision data collected by the ATLAS detector. The first is a $t\bar{t}$ (top-quark pair production) cross-section measurement that is used to improve our understanding of the internal structure of the proton. The second is a search for t-channel single-top-quark production. The pair production cross-section was measured individually in both the dilepton and single-lepton channels of the $t\bar{t}$ decay before being combined. The measurement in the single-lepton channel is also currently the most precise measurement of the top-quark pair production cross-section by the ATLAS Collaboration to date. The t-channel cross-section is measured in the semi-leptonic decay of the top quark and is the first observation of this process at a centre-of-mass energy of 5.02 TeV.

Speaker: Dr Sahibjeet Singh (Brookhaven National Laboratory (US))

399 Measurement of 𝐻 → 𝑍𝑍∗ → 4l and H → μμ using the ATLAS detector at the LHC

The Large Hadron Collider (LHC) is the most powerful particle accelerator ever built, designed to test the Standard Model and probe new frontiers in physics. One of its primary objectives was the discovery of the Higgs boson, whose detection confirmed the mechanism of electroweak symmetry breaking and explained the origin of mass for weak force mediators. The current focus of Higgs studies at the LHC is to study detailed properties of the Higgs boson, such as measuring kinematic distributions, its interaction strength (coupling) to other particles, and to establish evidence for its rare interactions.

This talk presents a recent measurement of Higgs boson properties that uses pp collision data at √s = 13.6 TeV recorded during 2022-2023. The analysis focus on the so-called 'golden channel' where the Higgs boson decays into four leptons (𝐻 → 𝑍𝑍∗ → 4l, where l = e or μ), which has a small branching ratio but allows for precise measurements due to the ATLAS detector's excellent lepton momentum resolution and high identification efficiency. Modern machine learning techniques are used to enhance the precision of the measurements, which includes: production cross sections of the different Higgs production modes; Higgs coupling strengths to fermions and vector bosons; differential cross sections for multiple observables; and, constraints on the Higgs boson self-coupling and interpretations within an effective field theory framework.

A second focus of the talk is of the H → μμ decay, which has not yet been conclusively observed. A measurement of this very rare decay would establish the Higgs boson's interactions with second-generation fermions at the LHC. Despite being a relatively clean final state, it faces a significant irreducible background from Drell-Yan production and a small H → μμ branching fraction. An analysis based on data collected by ATLAS in 2015-2018 is presented, and ideas for improvements using novel techniques are discussed.

Speaker: Magda Diamantopoulou (Carleton University (CA))

400 Not So Straightforward: Linear Fits in Real Life

Imagine constructing a cosmic ray detector: a few layers of scintillator, some SiPMs, and an excited student wiring it all together. Easy! Your design is segmented to allow for tracking, but what is the best way to reconstruct that track? How do you properly account for all positions within a scintillator volume being equally likely? Come join me for a light-hearted talk about how to draw straight lines and how this applies to searches for new physics in proposed long-lived particle experiments.

Speaker: Caleb Miller

401 Inequality-based QCD Constraints on the Hadronic Vacuum Polarization Contribution to Muon $g-2$

With recent updates on the experimental measurement of the muon’s anomalous magnetic moment ($a_\mu=\left(g-2\right)_\mu/2$) at Fermilab, the discrepancy between experimental results and Standard Model predictions is heightened to $5.0\sigma$. Along with the dependencies between the theoretical predictions from lattice QCD and data-driven methods, we establish upper and lower bounds for the hadronic vacuum polarization (HVP) contribution to the leading-order (LO) muon’s anomalous magnetic moment ($a_\mu^\text{HVP,LO}$) using the finite-energy QCD sum-rules (FESR) and H\"older inequalities.
Our results are evaluated up to five-loop order in perturbation theory in the chiral limit, LO in light-quark mass corrections, next-to-leading order in dimension-four QCD condensates, and LO in dimension-six QCD condensates, offering a path toward resolving the current tension in future investigations of the muon’s anomalous magnetic moment.

Speaker: Siyuan Li

(DASP) F1-2 Magnetosphere-Ionosphere Coupling | Couplage magnétosphère-ionosphère (DPAE)

Convener: Ian Mann (University of Alberta)

402 Statistical studies of polarisation and propagation characteristics of Pc5 ULF waves observed by SuperDARN Radars at mid latitudes

The bulk of information on polarisation and propagation of ultra-low frequency (ULF, 1-1000 mHz) waves is normally obtained using ground-based magnetometer arrays. However, the ground ULF field observations may be significantly distorted by the transition of the magnetohydrodynamic wave into an electromagnetic wave at the boundary between the ionised and neutral parts of the atmosphere. These effects include polarisation rotation and spatial integration altering the spatial patterns of wave’s amplitude and phase. In this respect, high-frequency (HF, 3-30~MHz) radars comprising the Super Dual Auroral Radar Network (SuperDARN) enable in situ observations of the ULF wave parameters at ionospheric altitudes by measuring plasma drift variations caused by the wave’s electric field. This study utlises data from several SuperDARN radars covering mid-latitude and sub-auroral regions to identify the predominant polarisation modes and azimuthal wave numbers of evening-to-morning ULF events in the Pc5 frequency band (1.67-6.67 mHz). The observed statistics of these waves single out the solar wind dynamic pressure variations and Kelvin-Helmholtz instability at the magnetopause as their potential generation mechanisms, although the drift-bounce resonance with trapped energetic ions might be responsible for the small-scale eng of the observed Pc5 waves.

Speaker: Pasha Ponomarenko (University of Saskatchewan)

403 Comparison of two-stream and kinetic methods of calculation of photoelectron effects

Photoelectrons are an important source of ionization and ambient electron heating in ionosphere. Primary photoelectrons are produced via ionization of neutral atoms in thermosphere by solar EUV photons. Secondary photoelectrons are produced via ionization by primary photoelectrons. There are different ways of calculation of photoelectron effects. The most accurate way is to use the kinetic approach where photoelectrons are represented as particles, propagation of photoelectrons along field lines is calculated using either the dynamics equations or the laws of conservation of energy and magnetic moment, and each collision between a photoelectron and a neutral is treated individually. The benefit of this approach is that there are no limiting assumptions on the shape of the photoelectron velocity distribution function. The drawback is the high numerical cost. Another way is the two-stream approach of Nagy and Banks [e.g. Journal of Geophysical Review, 75, 6260, 1970]. In this approach, the photoelectrons are separated into a number of energy bins, for each bin there is a flux of photoelectrons propagating downward and a flux propagating upward, and continuity equations are solved for the fluxes in each bin. This approach has significantly less numerical cost than the kinetic one, but it is potentially less accurate because it assumes that the photoelectrons are isotropic. In this paper, both the kinetic and the two-stream methods are applied to calculate photoelectron effects along the same field line. The resulting rates of ionization and heating, as well as fluxes of photoelectrons with different energies are compared. The deviation of the angular distribution of photoelectrons predicted by the kinetic method from isotropic is discussed.

Speaker: Dmytro Sydorenko

404 Unexpected Field-Aligned Structure in Equatorial Plasma Bubbles

Equatorial plasma bubbles (EPBs) are ionospheric irregularities which tend to be aligned parallel to the Earth's magnetic field. They are initated in the bottomside
of the F-region of the equatorial ionosphere by an instability
known as the Rayleigh-Taylor instability. EPBs impose effects on radio signals
and cause errors in Global Navigation Satellite Systems (GNSS) because
they alter the amplitude and phase of satellite signals. In this study, we
utilized 2 Hz plasma density
measurements from the Swarm satellite mission, which were collected in 2014, to study the characteristics of equatorial plasma bubbles, such as their size and occurrence frequency.
We used a smoothing filter to remove background levels and calculated the relative
plasma density to identify the boundaries of the bubbles based on a specified threshold.
We compared our results from the Communication/Navigation Outage Forecasting System (C/NOFs) satellite, which orbits in an easterly direction, whereas Swarm is in a polar orbit. Our results
show that plasma bubbles occur after sunset and before sunrise, as per previous research and theory. Although it is generally taken for granted that EPBs are relatively smooth along the geomagnetic field line, our study shows that bubble scale sizes are the same in both the Swarm and C/NOFs observations, despite the fact that Swarm flies predominantly along the magnetic field lines (B), while C/NOFs fly transverse
to them. This indicates that the bubble structure along the field lines is more significant than previously thought, which in turn suggests an unidentified source of plasma density structuring parallel to B.

Speaker: Bizuayehu Beyene (University of Calgary)

405 Validation of plasma drift velocity calculation algorithm

The paper discusses the validation of a 3D ionospheric drift velocity estimation algorithm developed by the authors. This algorithm will be integrated into the Sanimut system, which is being developed by the Radio and Space Physics Laboratory (RSPL) at the University of New Brunswick as a state-of-the-art, next-generation HF measurement platform. The system is set to replace the Canadian Advanced Digital Ionosonde (CADI) within the Space Weather Ionospheric Network Canada (SWINCan)—a successor to the Canadian High Arctic Ionospheric Network (CHAIN).
Both historical data from CADI ionosondes and data collected during field tests of a Sanimut-based ionosonde prototype were processed to validate the algorithm. A comparative analysis of drift velocities computed using the CADI software and those derived from the proposed algorithm demonstrated similar results. Notably, unlike the standard CADI software, the newly developed algorithm allows for velocity estimations even if one of the receiving channels fails. Additionally, it is designed to support calculations with arbitrarily positioned receiving antennas in 3D space, enhancing its flexibility and applicability.
The accuracy of the drift velocity calculation method was further validated through field tests of the Sanimut ionosonde prototype, conducted at the RSPL site near Blissville, New Brunswick. The validity of the results is supported by the consistency of diurnal drift velocity variations obtained during these tests, which align with simultaneous variations derived by the nearest digisonde, operated at Millstone Hill, Haystack Observatory, Massachusetts, USA. Furthermore, the algorithm was successfully tested at high-latitude SWINCan sites in Eureka and Resolute Bay, Nunavut.
Beyond analyzing experimental data, the study also addresses algorithm validation through computer simulations. The accuracy of the computed drift velocity is examined in relation to key factors, such as the phase difference measurement precision and the signal-to-noise ratio, across a range of expected drift velocity values.

Speaker: Dr Oleksandr Koloskov (University of New Brunswick)

406 Electron Density Variations in the Ionosphere Over Poker Flat (Alaska)

We present highly-averaged data on the ionospheric electron density to illustrate solar-cycle, seasonal, and diurnal variations over Poker Flat (Alaska) for the period of 2010-2019. Considered are measurements by the PFISR incoherent scatter radar and onboard Swarm satellites (at ~ 450 and 510 km) and predictions by the e-CHAIM empirical model. We demonstrate major expected dependencies and focus on minor differences between the instruments and the model.

Speaker: Hayden Fast (U of Saskatchewan)

(DPMB) F1-3 | (DPMB)

F-PLEN1 Plenary Session | Session plénière - Naoko Kurahashi Neilson, Drexel U.

407 The Milky Way In High-Energy Neutrinos - From the Intersection of Astrophysics and High-Energy Particle Physics

The Universe has been studied using light since the dawn of astronomy, when starlight captured the human eye. While astronomy has grown to include different wavelengths of the electromagnetic spectrum, "Neutrino Astronomy" offers a new way to observe and understand our high-energy Universe through neutrino particle physics as. In 2023, our own Galaxy was observed for the first time in neutrinos, making this the first non-electromagnetic image of the Milky Way. This talk covers Neutrino Astronomy as the intersection of astronomy, particle physics, and high-energy physics, and what it can offer to each of those fields.

Speaker: Naoko Kurahashi Neilson

Close of Congress | Fermeture du Congrès

IPP AGM | AGA de l'IPP

IPP Institutional and Board Meetings | Réunions institutionnelles et du conseil d'administration de l'IPP