Conveners
Plenary: 1
- Paul Campbell
Plenary: 2
- Michael Block
Plenary: 3
- Tommi Eronen
Plenary: 4
- Shuichi HASEGAWA (The University of Tokyo)
Plenary: 5
- Iain Moore
Plenary: 6
- Ari Jokinen (University of Jyvaskyla (FI))
Plenary: 7
- Daniel Rodrรญguez (Universidad de Granada)
Plenary: 8
- Magdalena Kowalska (CERN)
Plenary: 9
- Thomas Elias Cocolios (KU Leuven - IKS)
Plenary: 10
- Jens Lassen
Plenary: 11
- Piet Van Duppen (KU Leuven (BE))
Plenary: 12
- Anu Kankainen (University of Jyvรคskylรค)
Plenary: 13
- Klaus Wendt
Plenary: Plenary 14
- Klaus Wendt
Plenary: 15
- Mikael Reponen (University of Jyvaskyla (FI))
Plenary: 16
- Anna Kwiatkowski
Laser spectroscopy of highly charged ions at the Experimental Storage Ring (ESR) at GSI has a long tradition and started in 1994 with the observation of the hyperfine transition in $^{209}$Bi$^{82+}$ [1]. While carried out to test QED in the strongest magnetic fields available in the laboratory, it turned out that uncertainties in the nuclear structure contributions, specificially the nuclear...
The nuclear charge radius is a key observable in nuclear structure studies. Using the Collinear Apparatus for Laser Spectroscopy and Applied Physics (COALA) at the Institute of Nuclear Physics of TU Darmstadt, an all-optical approach for the nuclear charge radius determination was tested with the well-known nucleus of $^{12}$C. Here, the nuclear charge radius of $^{12}$C was extracted purely...
High-resolution laser spectroscopy is a powerful tool to extract nuclear structure data in a nuclear-model-independent manner. The isotope shift gives direct access to changes in mean-square charge radii, while the extracted hyperfine parameters give access to the nuclear spin, magnetic dipole and electric quadrupole moment. All this provides information on e.g. deformation, shape coexistence...
The Low-Energy Beam and Ion Trap (LEBIT) facility [1] at the recently commissioned Facility for Rare Isotope Beams (FRIB) remains the only facility that employs Penning trap mass spectrometry for high-precision mass measurements of rare isotopes produced via projectile fragmentation. This powerful combination of a fast, chemically insensitive rare isotope production method with a...
Investigating nuclear structure, especially nuclear shells and their associated magic numbers, has been an important field of research in the last decades. Such proton and neutron numbers are associated with sudden changes in nuclear observables between neighboring isotopes, such as binding energies, charge radii, transition strengths, etc. With $N=50$ neutrons and $Z=28$ protons, the...
High precision atomic mass spectrometry of neutron-rich rare-earth nuclides near A$\sim$165 was performed recently with the JYFLTRAP double Penning trap [1] using the phase-imaging ion cyclotron resonance technique [2] at the IGISOL facility in the JYFL Accelerator Laboratory. Altogether eighteen masses accross the lanthanum, terbium, dysprosium and holmium isotopic chains were measured,...
TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN) is a set of connected ion traps for rare isotope science. TITAN operates a Multi-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS) primarily for nuclear mass measurements and isomerically selective ion beam cleaning. TITAN's MR-TOF-MS has demonstrated excellent dynamic range ($\sim10^8$), high-precision ($\frac{\delta m}{m} \sim...
Low-energy precision tests of electro-weak physics keep playing an essential role in the search for new physics beyond the Standard Model. Atomic parity violation (APV) experiments measure the strength of highly forbidden atomic transitions induced by the exchange of Z bosons between electrons and quarks in heavy atoms. APV is sensitive to additional interactions such as leptoquarks, and...
This contribution will introduce a new experiment at MIT in which ion trapping and laser spectroscopy techniques are combined for precision measurements of fundamental symmetries and yet-to-be-explored nuclear electroweak properties[ [arXiv:2310.11192]][1]. In particular, single trapped molecular ions can amplify the sensitivity to nuclear-spin-dependent parity-violating effects, such as the...
While both Charge-Parity (CP) symmetry, and more recently Time (T) symmetry have been directly shown to be violated in the weak interaction, it remains an open question whether new sources of CP violation could explain the matter-antimatter asymmetry in the universe. TRIUMFโs Neutral Atom Trap (TRINAT) is equipped to study the angular distribution of all decay products from spin-polarized beta...
Around us we see an universe filled with galaxies, stars and planets like ours. But when we look back to the Big Bang and the processes that created the matter in it, at first we observe that there should have been created the same amount of matter and antimatter, thus the universe would be empty or different than it is. Sakharov suggested several conditions to explain the matter-antimatter...
The world's first electron scattering off online-produced Radioisotope (RI) was successfully conducted at the SCRIT (Self-Confining RI Ion Target) electron scattering facility in RIKEN RI Beam Factory in Japan.
Electron scattering stands out as one of the most potent and reliable tools for investigating the structure of atomic nuclei, owing to the well-understood mechanism of electromagnetic...
During the Chernobyl reactor accident on April 26, 1986, radioactivity was in part released in the form of nuclear fuel particles. These so-called โhot particlesโ have various structures that belong to specific oxidation states of uranium. These oxidation states behave differently in the environment. We obtain individual particles by density separation with a poly tungsten solution. Via...
The long-lived radioactive carbon isotope 14C is widely used as a tracer in environmental and biomedical studies. We have developed a 14C analytical system based on highly sensitive cavity-enhanced laser absorption spectroscopy, i.e., cavity ring-down spectroscopy (CRDS), and demonstrated 14C tracer analysis in pharmacokinetics and other areas. In parallel with...
In recent years resonance ionization mass spectrometry (RIMS) has shown great progress in analyzing individual micrometer-sized samples. Selective laser ionization of elements resolves most of the abundant isobaric interferences in complex matrices, like spent nuclear fuel. In RIMS, laser light is aimed at a neutral atomic cloud sputtered from the sample surface by a pulsed primary ion source...
The thorium isotope $^{229}$Th has attracted a lot of interest over the past few decades. This is related to its extremely low-lying first excited state at $\sim$ 8 eV and long radiative lifetime of a few $10^{3} \, \mathrm{s}$ [1]. This makes $^{229}$Th an ideal candidate for a nuclear clock with outstanding properties promising a variety of applications [2].
Large band gap crystals such...
Using efficient laser ionization schemes is a key element when performing atom-at-a-time laser spectroscopy. Auto-ionizing states are often used to enhance ionization due to their higher cross sections compared to excitation directly to the continuum. Nonetheless, for certain elements, either such structures are absent or remain undiscovered [1]. Alternatively, another approach involves...
Actinide elements present a rich spectrum of nuclear structure phenomena, and have been the focus of many research programs aimed at developing a detailed picture of this region of the nuclear chart. For example, theoretical models have predicted the emergence of pronounced reflection-asymmetric shapes moving towards more neutron-deficient isotopes[1]. The region also hosts two unique...
Static octupole deformation, also called reflection asymmetric by contrast with the quadrupole deformation, displays a profound signature on the observables and systematics of the nuclear ground state $[1]$ and are expected to manifest mostly in the heavier Actinides region of the nuclear chart. Such deformations present a non-negligible impact on the excitation spectra and nuclear properties,...
The N=126 factory is a new facility that uses multi-nucleon transfer reactions to create neutron-rich isotopes of the heaviest elements for studies of interest to the formation of the last abundance peak in the r-process. This region of the nuclear chart is difficult to access by standard fragmentation or spallation reactions and as a result has remained mostly unexplored. The nuclei of...
We have developed the KEK Isotope Separation System (KISS) [1] at RIKEN to study the nuclear structure of the nuclei in the vicinity of neutron magic number N = 126 and 238U from the astrophysical interest. These neutron-rich nuclei have been produced by using multinucleon transfer (MNT) reactions [2] with the combinations of the low-energy 136Xe/238U beams and the production targets of W,...
At the VITO beamline at ISOLDE [1], we use optical pumping with tunable lasers to polarise nuclear spins of different short-lived nuclei. We then use the resulting anisotropic emission of beta radiation in a variety of fields, from nuclear structure, via material science, all the way to biology.
Combining optical pumping with beta-decay detected nuclear resonance (beta-NMR) in liquid samples...
The MIRACLS experiment at ISOLDE/CERN combines the usage of ion traps and lasers to probe exotic radioactive nuclides [1]. In order to increase the sensitivity of fluorescence-based collinear laser spectroscopy (CLS), MIRACLS traps ion bunches in a Multi-Reflection Time of Flight (MR-ToF) device. Hence, the ions are probed multiple times instead of just once. This increases the laser-ion...
While nuclear shell effects are responsible for the existence of the heaviest elements, their atomic structure is strongly influenced by relativistic effects that lead to different atomic and chemical properties than their lighter homologs. Here, laser spectroscopy is a powerful tool for revealing fundamental atomic and also nuclear properties, which are reflected as subtle changes in the...
The 60-day spontaneously fissioning isotope californium-254 is the most neutron-rich known isotope of this element. Due to its anomalously long half-life, it is predicted to have a particularly high impact on the brightness of electromagnetic transients associated with neutron star mergers on the timescale of 10 to 250 days [Zhu et al., AJL 863, L23 (2018)]. Experimental information on Cf-254...
Laser spectroscopy provides information about the fundamental properties of atomic and nuclear structure of the constituents of matter. Measurements are of general importance all along the nuclear chart but are specifically thrilling for the heavy actinides and superheavy elements, where data is sparse and theoretical descriptions can be tested. For an extensive measurement campaign at the...
Atoms of different elements possess distinct spectra which serve as their fingerprints. Beyond providing information about the internal atomic and nuclear structure, knowledge of their spectra has allowed their identification in extragalactic stars and even neutron star mergers. However, very little is known about elements beyond fermium ($_{100}$Fm), which can only be synthesized in trace...
At the edges of the nuclear landscape, a rare form of radioactive decay occurs where the nucleus emits a proton. But what is the shape of the nucleus in the moments before it emits a proton? And how does the shape of the nucleus change when the proton becomes unbound? Studying nuclei at the proton drip line with laser spectroscopy may help to provide insights into these questions.
Laser...
Radionuclide metrology techniques, as currently used for activity standardization, show a large variety of measurement uncertainties โ from permille accuracy, e.g., for the ฮฑ-decaying isotope Am-241 (T1/2 = 432 a) up to few percent for Fe-55 (T1/2 = 2.73 a), which decays by electron capture. To reduce such uncertainties, a new standardization technique using direct ion beam implantation of the...
The electron affinity (EA) is the energy released when an additional electron is bound to a neutral atom, creating a negative ion. Due to a lack of long-range Coulomb attraction, the EA is dominated by electron-electron interactions, making negative ions excellent systems to probe these effects. A particular example is the determination of the specific mass shift, which is of importance when...
Laser excitation and manipulation techniques offer unique control of an atomโs external and internal degrees of freedom. The species of interest can be selectively captured, cooled, and observed with high signal-to-noise ratio down to the single atom level. Moreover, the atomโs electronic and magnetic state populations can be precisely manipulated and interrogated. Applied in nuclear physics,...
At the BEam COoling LAser spectroscopy (BECOLA) facility at the Facility for Rare Isotope Beams (FRIB), a Resonance Ionization Spectroscopy Experiment (RISE) instrument has been newly commissioned. This addition to the BECOLA facility will allow for laser spectroscopy to be conducted through both collinear fluorescence and resonant ionization methods back to back in the same beamline. The...
The region of refractory metals below tin exhibits a diverse spectrum of nuclear phenomena, i.e., strong deformations and shape coexistence. Particularly, in the neutron-rich Ru isotopes, there are hints for triaxial ground state deformations. To investigate nuclear ground-state properties of short-lived isotopes with collinear laser spectroscopy, a new collinear setup, ATLANTIS โ the Argonne...
The key ingredient for mean-field calculations in nuclear structure is the
effective interaction which models the strong force in the nuclear medium.
Such interactions usually depend on a set of parameters fitted to
properties nuclei and infinite nuclear matter.
These interactions can suffer several limitations and problems. For
example, since they are usually adjusted on properties of...
Molecules that contain heavy and radioactive nuclei can be highly sensitive to a number of nuclear observables of interest, such as the typically studied nuclear magnetic dipole and electric quadrupole moments, but also symmetry-violating hadronic, leptonic, and nuclear moments.
Precision experiments based on heavy and polar radioactive molecules have been proposed as being potentially the...
Theory can provide important support at all the stages of spectroscopic experiments, from planning the measurements, through extracting the properties of interest from the data, and to the interpretation of the results and their comparison to theoretically predicted values. To be reliable and useful in experimental context, theoretical predictions should be based on high accuracy calculations....
Resonant laser secondary neutral mass spectrometry (rL-SNMS) combines the spatial resolution traditional ToF-SIMS with the elemental selectivity of resonant laser ionisation. This quasi non-destructive method is an ideal choice for the analyses of micron sized fragments of nuclear fuel, so called โhot particlesโ from the Chornobyl exclusion zone [1]. With this method actinides in single...
S3LEB (Super Separator Spectrometer-Low Energy Branch) is a low energy radioactive ion beam facility, which will be employed for the study of exotic nuclei, under commissioning as a part of GANIL-SPIRAL2 facility [1]. High intensity primary beams, delivered by the superconducting LINAC of the SPIRAL2 facility, will allow for increased production rate for nuclear fusion evaporation reaction,...
The heavy $N=Z$ nuclei and the nuclei in their vicinity are highly interesting to study; they can provide important insights about nuclear structure, symmetries and interactions and have a high impact in modelling nuclear astrophysics processes ($rp$-process, $\nu p$-process). A few examples of the striking phenomena are the formation of high-spin isomeric states, the direct and/or...
The N=Z nucleus 94Ag has intrigued physicists for decades thanks to its unique decay modes, long-living isomeric states, and structure. Most notably, the existence of an elusive two-proton decay channel in its spin 21+ isomeric state has been a subject of debate since its first reports in 2006 [1]. Subsequent investigations of 94Ag have not found evidence of two-proton emission, although other...
How does the size and deformation of the silver nucleus evolve as a function of neutron number as one moves between two exotic neutron shell closures, N=50 and N=82, and can modern nuclear theoretical methods accurately predict the trends? To address this question, experiments in recent years have been performed at the IGISOL facility using collinear laser spectroscopy [1] and in-source...
As nuclides become increasingly exotic, production yields fall off; contamination increases; and, often the half lives drop. To meet these challenges, developments at the TITAN-TRIUMF facility are continually underway. Its Multi-Reflection Time-Of-Flight (MR-TOF) mass separator has become the preferred tool in probing the limits of radioactive-ion-beam production at TRIUMF via high-precision...
High-precision mass measurements of radioactive ions are used to determine nuclear binding energies, which reflect all forces acting in the nucleus and are used to study among others nuclear structure, nuclear astrophysics, and weak interaction.
For this, the ISOLTRAP mass spectrometer at ISOLDE/CERN [1] uses various ion traps, including a tandem Penning-trap system and a multi-reflection...
Speculation about the existence of elements heavier than uranium started in the late 19th century [1]. Thanks to an increased understanding of nuclear structure and decades of developments, transuranic and eventually superheavy elements were discovered [2]. The latter owe their existence to nuclear shell effects, which enhance their stability [3]. The strength of these effects can...
A new method for the determination of the eigenfrequencies of laser-cooled ions in a Penning trap has been recently demonstrated. It relies on the measurement of the ionโs motional amplitude using the scattered photons when an internal optical electric dipole transition is addressed by lasers [1]. Compared to other techniques, it is universal regarding the mass-to-charge ratio, it is...
Muonium (Mu = $\mu^+$ + $e^โ$) is a purely leptonic, two-body exotic atom amenable for precision measurements of fundamental constants ($m_\mu$, $\mu_\mu$) and tests of bound state QED. Mu also offers the possibility to directly test the coupling of gravity to second generation elementary (anti)leptons, a system where there are no contributions to the mass by the strong interaction. Hence,...
Muonic atom spectroscopy is a technique that studies the atomic transitions between levels that are occupied by muons orbiting a nucleus. Due to the heavier mass of muons with respect to that of electrons, its atomic orbitals will be substantially closer to the nucleus. Consequently, the sensitivity to nuclear effects is enhanced. In particular, muonic atoms have an increased sensitivity to...
The atom-trap facility at the Ion-Guide Isotope Separator On-Line (IGISOL) at the University of Jyvรคskylรค has been developed for cooling and trapping a chain of isotopes and isomers of caesium [1]. This would allow a high-precision spectroscopy from which a nuclear magnetic octupole moment can be deduced, an important parameter which helps validate nuclear theory and reveal insight on the...
Using convectional collinear laser spectroscopy techniques, the Bohr-Weisskopf effect(BWE) is frequently found to be at a similar level to the experimental uncertainty. Therefore, the study of this effect has been mainly limited to stable isotopes, where higher precision can be obtained. Despite the limited information, this effect could in principle provide significant new information on both...
At the Institute for Nuclear and Radiation Physics of KU Leuven (IKS) we started a project to measure data on the magnetic octupole moment ($\Omega$) of single valence radioactive nuclei. While currently this observable has only scarcely been measured, and is thus poorly understood, preliminary shell model and Density functional theory (DFT) calculations indicate $\Omega$ may display a strong...
On-line in-source laser resonance ionization is a highly sensitive tool for nuclear structure investigations [1]. While the efficiency of this technique is unrivaled, the experimental resolution is ultimately limited by Doppler broadening in the hot cavity required to ensure atom volatilization. At typical operation temperatures around 2000 ยฐC, this leads to a several GHz limit, whereas...
Laser spectroscopy is one of the most powerful tools for studying ground and isomeric state nuclear properties. By observing small changes in atomic transitions, we can deduce the nuclear spin, electromagnetic moments, and changes in mean-square charge radii across long chains of isotopes. This allows us to study how the shapes and the configurations of the nuclei vary along the chain and...
Resonance ionization laser ion source (RILIS) has been developed as part of the ISOL ion sources at RAON in the Institute for Rare Isotope Science, Korea. The RAON RILIS based on Ti:sapphire lasers has been developed with a long laser beam transport system over 30 m. To develop optimal laser ionization schemes and investigate the RILIS efficiency, an off-line test facility adjacent to the...
The observation of double-beta decays and double-electron captures have become an important tool in the search for physics beyond the Standard Model (SM). These decays have been proposed to decay by emitting either two neutrinos or no neutrinos. While the two neutrino mode has been observed [1], the proposed neutrinoless decay mode requires the neutrino to be its own antiparticle (a Majorana...
High-precision measurements of single ฮฒ$^{ยฑ}$ decays or electron capture (EC) are the most model-independent methods to determine the absolute scale of the (anti)neutrino mass. Decay transitions with the lowest possible Q value are desirable. Currently, only three nuclei with low ground-state-to-ground-state (gs-to-gs) decay Q values are employed for direct neutrino-mass measurements [1-3]....
The laser applications group at TRIUMF - Canada's particle accelerator centre is tasked to provide clean and intense beams of radioactive isotopes for user experiments. This is done through in-source laser resonance ionization (running a laser ion source or derivatives thereof). Beam delivery activities and highlights of the RIB delivery and development program of the past years will be...
Selective and efficient ionization using multi-step resonant laser excitation processes has become the most versatile and widely used technique in the production and study of exotic species, both for research on their atomic or nuclear structure at the different on-line facilities worldwide as well as for applications in isotope purification for fundamental investigations or for the production...
