XVIII Conference on Resistive Plate Chambers and Related Detectors

14 Sept 2026, 07:50 → 18 Sept 2026, 17:00 America/Sao_Paulo

Sandro Fonseca (Universidade do Estado do Rio de Janeiro (BR)), Gilvan Augusto Alves (CBPF - Brazilian Center for Physics Research (BR))

The 2026 International Conference on Resistive Plate Chambers and Related Detectors (RPC Conference), the eighteenth edition, will be held in Rio de Janeiro, Brazil, from September 14-18, at the Rio de Janeiro State University (UERJ), supported by UERJ and the Brazilian Center for Physics Research (CBPF). This marks the first time the conference is held in Brazil and its return to Latin America, continuing a tradition that began in Lecce in 1991.

 

Official Website: https://rpc2026.uerj.br/

First_Bulletin_RPC_2026Nov2025.pdf

Fourth Bulletin RPC 2026 Letter_June24.pdf

PosterLocalRPC

PosterRPC2026V16.pdf

Second_Bulletin_RPC_2026_Feb2026.pdf

Third_Bulletin_RPC_2026_June092026.pdf

Monday 14 September

07:50 → 08:30 Registration: Overture

Entry to auditorium 111 (UERJ/Maracanã)

08:30 → 08:50 Welcome session

Auditorium 111 (UERJ/Maracanã)

Conveners: Gilvan Augusto Alves (CBPF - Brazilian Center for Physics Research (BR)), Sandro Fonseca (Universidade do Estado do Rio de Janeiro (BR))

08:50 → 09:20 Plenary session

Auditorium 111 (UERJ/Maracanã)

Convener: Wagner De Paula Carvalho (Universidade do Estado do Rio de Janeiro (BR))

08:50 Muon systems in FCC-ee detector concepts

Speaker: Riccardo Farinelli (INFN Bologna (IT))

09:20 → 10:00 HEP performance

Auditorium 111 (UERJ/Maracanã)
The session is dedicated to the operation and performance of RPC/MRPC systems in HEP experiments (efficiency, timing, rate capability, trigger/reconstruction, stability, Run/upgrade performance.

Convener: Wagner De Paula Carvalho (Universidade do Estado do Rio de Janeiro (BR))

09:20 Operation and performance of the CMS RPC system during LHC Run 3 data taking

Run 3 data taking of the LHC will conclude in the summer of 2026. So far, the CMS experiment has accumulated 30.36 fb⁻¹ of proton-proton collision data at a center-of-mass energy of 13.6 TeV in 2026 alone, bringing the total for the entire Run 3 to 326.03 fb⁻¹. The CMS experiment is designed to identify muons robustly, efficiently and redundantly. One of the detectors used for this purpose is part of the muon system and consists of resistive plate chambers (RPC). These detectors are present in both the barrel and endcap regions. The RPCs undergo calibrations to optimize the operating voltage of each chamber and ensure stable detector performance under varying running conditions. In parallel, several performance and operational studies are carried out to guarantee high data quality and reliable detector operation. The latest RPC performance results will be presented, including the most recent calibrations performed on the detector. These results will cover detector efficiency, cluster size, and operational stability. A summary of the ongoing upgrade activities and their current status will also be presented.

Speaker: Andres Leonardo Cabrera Mora (Universidad de los Andes (CO))

09:40 Performance of the ATLAS Resistive Plate Chamber System during LHC operations

Resistive Plate Chambers (RPCs) have played a crucial role as muon-trigger detectors in the major experiments at the Large Hadron Collider (LHC), including ATLAS, CMS, and ALICE, since the beginning of LHC operations. In the ATLAS experiment, RPCs provide fast trigger signals for muon identification in the barrel region and constitute a fundamental component of the Level-1 (L1) muon trigger system, responsible for bunch-crossing identification and transverse-momentum threshold assignment. This contribution presents an overview of the performance of the ATLAS RPC detector system as well as the L1 Muon Barrel trigger during LHC operations.

Speaker: Paolo Camarri (INFN e Universita Roma Tor Vergata (IT))

10:00 → 10:30 Coffee break

11th-floor lobby, Block F, near Auditorium 111

10:30 → 11:50 HEP performance

Auditorium 111 (UERJ/Maracanã)
The session is dedicated to the operation and performance of RPC/MRPC systems in HEP experiments (efficiency, timing, rate capability, trigger/reconstruction, stability, Run/upgrade performance.

Conveners: Dilson De Jesus Damiao (Universidade do Estado do Rio de Janeiro (BR)), Mapse Barroso Ferreira Filho (Universidade do Estado do Rio de Janeiro (BR))

10:30 Towards High-Performance Thin-Glass RPCs for the Next Generation of Collider Experiments

Future collider experiments impose stringent requirements on muon detector technologies, demanding large-area coverage at low cost per channel, high detection efficiency, time resolution on the order of a few hundred picoseconds, and long-term operational stability. Resistive Plate Chambers (RPCs) remain strong candidates for next-generation muon systems, and ongoing R&D is pursuing thin-gap glass RPC designs that aim to meet these performance targets.
This work reports on the characterization of thin-gap glass RPC prototypes, including double-gap and double bi-gap layouts with 500 μm gas gaps, tested with cosmic rays and under beam conditions. Time resolution measurements demonstrate that these prototypes achieve values of approximately 200 ps, establishing thin-gap glass RPCs as competitive candidates for future collider muon systems. Operational working points, signal charge spectra, and detection efficiency are reported alongside performance evaluations using different gas mixtures. Improved spatial resolution through charge-centroid analysis is also discussed. Taken together, these results establish the viability of thin-glass RPCs as a high-performance, robust, and scalable detector technology.

Speaker: Dayron Ramos Lopez (Universita e INFN, Bari (IT))

10:50 Operation and performance of the ALICE Muon IDentifier RPCs during LHC Run 3

ALICE (A Large Ion Collider Experiment) is a multi-purpose detector installed at the CERN Large Hadron Collider (LHC). Its main goal is the characterization of the quark-gluon plasma (QGP) in ultra-relativistic heavy-ion collisions. The QGP is a state of nuclear matter where quarks and gluons are not confined into hadrons. In the forward rapidity region (2.5 < y < 4) ALICE is equipped with a muon spectrometer (MS), allowing the study of the muonic decays of quarkonia (bound states of cc̄ and bb̄ quarks) and open heavy-flavor particles, both key probes to investigate QGP properties.

During the LHC Run 1 and Run 2, event selection in the MS was based on a hardware trigger provided by a set of 72 Resistive Plate Chambers (RPCs) operated in maxi-avalanche mode and referred to as Muon Trigger (MTR). Following a successful upgrade during the LHC Long Shutdown 2 (2019-2022), ALICE is now taking data in continuous readout mode, without a hardware trigger and the Muon Trigger has evolved into a Muon Identifier (MID).

To cope with increased luminosities, reduce aging and enable triggerless readout mode, two major upgrades were carried out. Front-end electronics now include a pre-amplification stage, allowing to switch to avalanche mode and to lower both thresholds and high voltages, while back-end electronics were adapted for continuous readout. These upgrades allow the detector to operate safely and efficiently at a hadronic interaction rate of 50 kHz in Pb-Pb collisions, an increase by more than a factor 5 with respect to Run 2.

A summary of the MID operation during the whole LHC Run 3 will be presented in the contribution. This includes an overview of the RPC performance in terms of efficiency, dark current, dark counting rate and data quality, as well as a report on the charge integrated during Run 3 and a comparison with the Run 1 and Run 2 trends.

Speaker: Luca Quaglia (Universita e INFN Torino (IT))

11:10 Development and Validation of the iRPC Back-End Electronics Prototype for CMS Phase-II Upgrade

The iRPC (improved Resistive Plate Chamber) is a newly introduced detector in the CMS Phase-II Upgrade, designed to enhance muon detection efficiency in the high-luminosity LHC environment. In order to study the performance of iRPC and R&D on the key technology of Backend Electronics, a prototype back-end electronics (BE) system based on the MicroTCA (µTCA) architecture has been developed and subjected to comprehensive full-chain validation. The prototype system has been evaluated across multiple testing stages. Verification of backend electronics functionality was conducted through cosmic ray experiments in CERN 904 laboratory and beam test in CERN Gamma Irradiation Facility. Subsequently, the system was deployed at CERN Point 5 (P5) and commissioned with real LHC stable beam collision data, enabling validation under authentic experimental conditions prior to Long Shutdown 3 (LS3). A key milestone was the successful integration of the iRPC back-end electronics with the CMS Global Trigger (L1A) and the Trigger Control and Distribution System (TCDS) at P5. These efforts resulted in the acquisition of genuine iRPC detector hit data, providing valuable input for ongoing detector and electronics study. In addition, joint commissioning tests were conducted with the Endcap Muon Track Finder (EMTF), iRPC cluster data together with other Endcap Muon data will be expected before LS3. Preliminary data analysis results demonstrate that the µTCA-based iRPC back-end electronics prototype meets the functional requirements for CMS Phase-II. The successful full-chain validation, from standalone bench tests to in-situ P5 integration, establishes a solid foundation for the final system design in LS3 installation. In this talk, more details about key technology of iRPC BE, set-up at P5 and data analysis results will be reported.

Speaker: Canming Li (Chinese Academy of Sciences (CN))

11:30 The long term performance of MRPCs in the ALICE TOF and the Extreme Energy Events detectors

Multigap Resistive Plate Chambers (MRPCs) are gaseous detectors of choice for nuclear and particle physics experiments given their excellent time resolution, high efficiency and low cost. Among others, two large-area experiments have employed MRPCs for over 15 years: the ALICE Time-of-Flight (TOF) detector at the LHC and the Extreme Energy Events project (EEE).

The ALICE TOF is a key Particle IDentification (PID) system at intermediate momenta. It consists of $1593$ MRPCs ($\sim900$ cm$^2$ each) operating with a mixture of C$_2$H$_2$F$_2$ (93$\%$) and SF$_6$ (7$\%$), covering an active area of $\sim140$ m$^2$ with over $150000$ readout channels. A global time resolution of $\sim$60 ps has been achieved, with stable performance since 2009 and no signs of degradation. During LHC Long Shutdown 2, the readout and the online-offline (O$^2$) framework were upgraded to handle the targeted 50 kHz Pb–Pb interaction rate via a continuous readout scheme. The TOF performance along with selected PID results from LHC Run 3 will be discussed.

The same technology with a different layout is employed in the Extreme Energy Events project, a network of $\sim 50$ tracking telescopes mostly hosted in Italian high schools studying cosmic rays and supporting outreach. Each telescope consists of three MRPCs ($\sim13000$ cm$^2$ each) operated until 2020 with a $\text{C}_2\text{H}_2\text{F}_4$ ($98\%$) and $\text{SF}_6$ ($2\%$) mixture. Recent R&D efforts focus on eco-friendly gas mixtures such as helium- and R1234ze-based solutions, now in use in several telescopes. A compact gas recirculation system is also under development to reduce gas consumption. Detector performance with the new gas mixtures and preliminary recirculation tests will be presented.

Speaker: Bianca Sabiu (Universita e INFN, Bologna (IT))

11:50 → 13:50 Lunch Time

13:50 → 14:30 Satellite Seminar

Auditorium 111 (UERJ/Maracanã)

Convener: Mapse Barroso Ferreira Filho (Universidade do Estado do Rio de Janeiro (BR))

13:50 Elsevier Author Workshop

This workshop offers a comprehensive overview of Elsevier and its various products, including an introduction to Elsevier's High Energy Physics portfolio and the key features that support researchers in this field. Participants will gain valuable insights into our commitment to research integrity and publishing ethics, fostering responsible and transparent scholarly communication. The session will also cover Elsevier's AI policies and recent updates, highlighting how technological advancements are being integrated into our publishing practices. Designed to equip authors with essential knowledge, this workshop aims to promote best practices and enhance their overall publishing experience with Elsevier.

Speaker: Tanur Sinha (Elsevier Limited, UK)

14:30 → 14:50 HEP performance

Auditorium 111 (UERJ/Maracanã)
The session is dedicated to the operation and performance of RPC/MRPC systems in HEP experiments (efficiency, timing, rate capability, trigger/reconstruction, stability, Run/upgrade performance.

Convener: Mapse Barroso Ferreira Filho (Universidade do Estado do Rio de Janeiro (BR))

14:30 Resistive Plate Chambers as charged-particle trigger detectors: from the HL- LHC to the FCC

The R&D activity which was needed for the required upgrade of the RPCs in view of the HL-LHC operation paves the way to the development of next-generation RPCs for general-purpose experiments at future colliders such as the Future Circular Collider (FCC) foreseen at CERN. The first big step will be the FCC-ee, which will study collisions of electron and positron beams with a center-of-mass energy between 90 and 350 GeV. The experiments at the FCC-ee will not need high rate capability due to the low background in lepton-lepton collisions. This offers an excellent opportunity for devising a stand-alone subdetector integrating the functions of charged-particle triggering, timing and tracking. This will require very good time response and time resolution, in view of detailed and highly significant checks of all the known SM processes (in particular beauty, top, and Higgs physics) and of possible and yet unknown new physics. The second big step will be the FCC-hh, which will study the collision of proton beams with a center-of-mass energy of 100 TeV, which will extend the search for new resonant states up to about 30 TeV. In this phase, high rate capability and radiation hardness will be major requirements, due to the extremely high particle pile-up in high-energy proton-proton collisions. RPCs, based on their performance in the experiments at the Large Hadron Collider, where they worked fine in a high-pile-up environment, showing very good rate capability and radiation hardness, will be a natural detection technology for a muon-trigger subdetector at the FCC-hh. In summary, the RPC is a natural candidate for the next-generation charged-particle trigger subdetector in both phases of the FCC. The main features of the upgraded RPC subdetector at the HL-LHC will be discussed, and the possible use of RPCs at the FCC will be described.

Speaker: Paolo Camarri (Università degli Studi di Roma "Tor Vergata" and INFN Roma Tor Vergata)

14:50 → 15:50 Physics and Simulation

Auditorium 111 (UERJ/Maracanã)

Convener: Mauricio Thiel (Universidade do Estado do Rio de Janeiro (BR))

14:50 A Standalone Simulation Framework for the Physical Modeling of Resistive Plate Chambers (RPCs) and Resistive Cylindrical Chambers (RCCs)

Within the framework of the TANGO_RD project, a novel gas detector architecture known as Resistive Cylindrical Chambers (RCC) is under active investigation. To effectively guide the hardware R&D, we are developing a dedicated, standalone simulation program. Designed to natively support both traditional planar geometries and the new cylindrical ones, this custom C++ framework relies on strategic physical simplifications to provide a highly flexible and computationally fast environment. In this contribution, we will present the core architecture of the software and discuss the peculiar electrostatic characteristics introduced by the cylindrical configuration. Particular emphasis will be placed on the critical role of the electric field polarity, which profoundly influences avalanche evolution, and space charge dynamics. Finally, we will showcase the expected performance for typical configurations and validate the simulation model by comparing its predictions against established experimental data from standard planar RPCs, alongside preliminary results from early RCC prototypes.

Speaker: Davide Piccolo (INFN e Laboratori Nazionali di Frascati (IT))

15:10 Dynamic Multiscale Simulation of Avalanche-Induced Field Perturbations in RPC Detectors

Resistive Plate Chambers (RPCs) are commonly simulated using a multiscale approach in which Geant4 describes particle transport and energy deposition, while Garfield++ models gas ionization and avalanche development. In most existing workflows, these two frameworks are coupled sequentially: Geant4 outputs are exported and subsequently processed by Garfield++, preventing microscopic ava- lanche information from influencing the ongoing detector simulation.
In this contribution, we present a dynamic Geant4–Garfield++ interface designed to enable event- by-event microscopic feedback during detector operation. Whenever a charged particle traverses the gas gap, the simulation is temporarily transferred from Geant4 to Garfield++, where primary ionization, avalanche growth, and charge production are evaluated. The resulting avalanche charge is then used to estimate local perturbations of the electric field and an effective local voltage drop within the gas volume. This information is returned to Geant4, allowing the detector state to be updated before the simulation proceeds.
The proposed framework introduces a self-consistent multiscale description in which microscopic avalanche dynamics can modify macroscopic detector conditions during the same event. This enables the reconstruction of new observables that are generally inaccessible in conventional offline coupling schemes, including local voltage-drop distributions, effective field distributions, and event-by-event field perturbations associated with avalanche development.
The methodology is particularly relevant for studies under GIF++-like irradiation conditions, whe- re the interplay between muons, gamma background, and local field distortions may influence detector performance. Rather than treating the electric field as a static quantity, the framework allows it to evolve according to microscopic charge production, providing a new route toward dynamic RPC simu- lations and future investigations of detector response, rate effects, and operational stability.

Speaker: Victor Olenin Ramirez Beltran (Universidad Iberoamericana)

15:30 Gaseous Detector Resistive Plates beyond the RC Paradigm

Resistive plates in gaseous detectors are commonly modelled as parallel RC circuits, possibly with a voltage-dependent resistance.
This approach has enabled substantial progress in the description of resistive-protection techniques, including induced-signal formation, rate capability, dynamic field fluctuations and charging-up times. However, real materials exhibit ideal RC-like behaviour only within a limited frequency range, if at all. As a result, deviations from the model are often absorbed into effective parameters, making it difficult to distinguish genuine material response from experimental uncertainty.

To clarify this situation, we performed impedance-spectroscopy measurements between 0.1 Hz and 10 MHz, complemented by DC measurements, on five resistive-plate materials: Bakelite, Chinese glass, low-resistive Williams glass, float glass and Fe₂O₃/YSZ ceramics, using different electrode contacts. The measurements were carried out as a function of temperature, allowing us to identify relaxation mechanisms and extract the corresponding activation energies. The observed behaviour is rich, but broadly falls into two classes: materials in which relaxation and conduction share the same activation energy, as expected for ion-conducting systems, and materials in which the two processes are decoupled, as more commonly found in electron-conducting systems.

We present the experimental results, discuss the implications of these different material classes for gaseous-detector operation, and compare standard RC predictions with those obtained from the measured response functions for several key performance quantities.

Speaker: Mr Xandre Álvarez González (USC)

15:50 → 16:20 Coffee break

11th-floor lobby, Block F, near Auditorium 111

16:20 → 17:00 Physics and Simulation

Auditorium 111 (UERJ/Maracanã)

Convener: Diego Torres Machado (Universidade do Estado do Rio de Janeiro)

16:20 Simulation Study of Ionization Rate Discrepancies in Pure Freon for Thin-Gap RPCs

There remains a significant discrepancy between the effective ionization rate measured at low pressure on a Pulsed Townsend (PT) setup and that obtained at ambient pressure with Resistive Plate Chambers (RPC). This mismatch becomes particularly pronounced at high reduced electric field strengths, i.e. equivalently in small-gap RPCs . In these fields, RPC measurements systematically yield lower ionization rates than PT measurements, with differences reaching several standard deviations.
To investigate this discrepancy, we analyze signal waveforms from RPC measurements of cosmic muons conducted at LIP Coimbra , using pure R-134a in a chamber with a variable gap distance. The experimental setup is simulated in detail, employing state-of-the-art detector physics tools to reproduce the measured waveforms and the ionization rate to be extracted using the two-threshold method as in the experimental procedure. The simulations use ionization rates calculated with Magboltz, based on pulsed Townsend measurements at low pressure.
We demonstrate how the ionization rate fed into the simulation is effectively modified when applying the two-threshold method, due to space-charge effects, electron diffusion, boundary conditions, and finite readout bandwidth. With this approach, we show that the observed discrepancy can be partially resolved.

Speaker: Dario Stocco

16:40 Study of CMS iRPC waveforms parameters and classification of signals using Machine Learning

Resistive plate chambers (RPCs) are widely used in high-energy physics. The induced signal is a waveform correlated with the avalanche production. Waveform studies, besides allowing the measurement of induced electric charge and time quantities, can also serve as a probe for analyzing individual avalanche processes. Given new regulations that drastically limit greenhouse gas emissions, including those from RPCs, such studies are essential for guiding the search for eco-friendly gas mixtures and for refining simulation tools like Garfield++ and Magboltz. In this work, we present a study of the waveforms produced by improved Resistive Plate Chambers (iRPCs) during the Muon test beam at the CERN Gamma Irradiation Facility, including a machine-learning-based analysis for signal classification. This tool will be used as a complementary method in the search for alternative mixtures, to improve understanding of the discharge processes of the candidates and to complement traditional analysis methods.

Speaker: Dalmo Da Silva Dalto (Universidade do Estado do Rio de Janeiro (BR))

17:00 → 18:00 Opening Ceremony

Auditorium 111 (UERJ/Maracanã)

Ceremony with local and national officials before the event's welcome cocktail reception. We will list the speakers soon.

Speakers: Gilvan Augusto Alves (CBPF - Brazilian Center for Physics Research (BR)), Sandro Fonseca (Universidade do Estado do Rio de Janeiro (BR))

18:00 → 20:00 Welcome Coquetel

Hall in the basement of the Ecumenical Chapel at UERJ

Tuesday 15 September

08:00 → 08:50 Registration

Entry to auditorium 111 (UERJ/Maracanã)

08:50 → 09:20 Plenary session

Auditorium 111 (UERJ/Maracanã)

Convener: Gilvan Augusto Alves (CBPF - Brazilian Center for Physics Research (BR))

08:50 Overview DRD1

Speaker: Marcello Abbrescia (Universita e INFN, Bari (IT))

09:20 → 10:00 Alternative Mixtures and Longevity

Auditorium 111 (UERJ/Maracanã)

This session is dedicated to Eco-gas R&D and long-term operation: low-GWP mixtures, gas systems/recirculation, irradiation and aging studies, impurities, and mitigation strategies.

Convener: Gilvan Augusto Alves (CBPF - Brazilian Center for Physics Research (BR))

09:20 Eco-friendly gas mixtures for RPCs: results from a long-term ageing study at CERN GIF++

Gaseous detectors are widely employed in high-energy physics experiments, where their operation often relies on fluorinated gases with a high Global Warming Potential. In light of increasing environmental awareness and tightening regulations, the identification of sustainable and low-impact gas mixtures has become a priority for the community.

Resistive Plate Chambers (RPCs) operated in avalanche mode typically make use of high-performance mixtures based on high-GWP gases such as C₂H₂F₄ and SF₆. Within the RPC ECOGas@GIF++ Collaboration, a dedicated long-term R&D program has focused on the identification of environmentally friendly alternatives and on the evaluation of their behaviour under irradiation. In this context, different RPCs filled with an HFO-1234ze/CO₂-based mixture have been exposed to intense radiation at the CERN GIF++ facility, reaching integrated charges of O(10² mC/cm²) over approximately three years. The ageing study has now been finalized, and the detector response has been characterized over a broad range of particle fluxes.
In this presentation, the final results of the ageing campaign will be reported, together with an overview of the implications for future RPC operation and gas mixture optimization.

Speaker: Marcello Abbrescia (Universita e INFN, Bari (IT))

09:40 Long-term operation of CMS improved Resistive Plate Chambers with alternative CO2-based mixture under high irradiation environment

Resistive Plate Chamber (RPC) detectors in the Compact Muon Solenoid (CMS) experiment operate with a gas mixture comprised of 95.2% of C2H2F4, that provides a high number of ion-electron pairs, 4.5% of iC4H10, that ensures the suppression of photon-feedback effects and 0.3% of SF6, used as an electron quencher to further operate the detector in streamer-free mode. C2H2F4 is known to be a Greenhouse gas with a very high global warming potential (GWP) of 1430. Several alternatives to C2H2F4 have been studied in the last few years. In this context, one short-mid term approach could be to focus on adding CO2 in place of C2H2F4. The studies are done at CERN Gamma Irradiation Facility (GIF++) in the North Area of SPS, where a 13.6 TBq radiation source and a muon beam from SPS are used to mimic the conditions of Phase-II of LHC. This work will present the performance and aging of a 1.4 mm gap RPC chamber with three different CO2-based mixtures under a high gamma background, as well as the results after a second round of longevity period, integrating 80 mC/cm^2 of charge, almost 30% of the 300 mC/cm^2 expected for the High Luminosity LHC (HL-LHC) period.

Speaker: Joao Pinheiro (Universidade do Estado do Rio de Janeiro (BR))

10:00 → 10:30 Coffee break

11th-floor lobby, Block F, near Auditorium 111

10:30 → 11:50 Alternative Mixtures and Longevity

Auditorium 111 (UERJ/Maracanã)

This session is dedicated to Eco-gas R&D and long-term operation: low-GWP mixtures, gas systems/recirculation, irradiation and aging studies, impurities, and mitigation strategies.

Conveners: Eliza Melo (Universidade do Estado do Rio de Janeiro (BR)), Mauricio Thiel (Universidade do Estado do Rio de Janeiro (BR))

10:30 Material studies on RPC detectors operated with HFO/CO$_{2}$-based eco-friendly gas mixtures

The gas mixtures employed in most RPC systems contain a high fraction of fluorinated greenhouse gases (F-gases), namely C2H2F4 (R134a) and SF6, which have been placed under intense scrutiny by the EU, aiming at a reduction in their availability and usage, making RPC operation more costly and less sustainable.

A possible long-term solution to this problem is to find eco-friendly alternatives to these gases. The RPC EcoGas@GIF++ collaboration investigated the full replacement of R134a with its industrial substitute, the tetrafluoropropene (C3H2F4 or simply HFO) diluted with CO2 in different concentrations. The studies consisted in carrying out several beam test campaigns and aging studies to investigate the RPC performance in terms of detection efficiency, prompt charge and long-term operational stability.

This contribution will present a complementary approach to the studies carried out thus far, where the focus of the research is shifted from RPC performance to detailed material studies of RPC components, before and after being exposed to HFO/CO2 mixtures, in different experimental conditions.

A variety of analytical techniques (Scanning Electron Microscope (SEM), coupled with Energy Dispersive X-ray (EDX), laser microscopy and resistivity measurements) have been applied to brand-new and aged materials, in an attempt to gain a deeper insight of the electrical and chemical modifications induced by the new gases. An overview of the obtained results and potential explanations for the observed effects will be reported in this contribution.

Speaker: Luca Quaglia (Universita e INFN Torino (IT))

10:50 Performance studies of HPL RPC detectors operated with alternatives to R-134a and SF6

Resistive Plate Chambers at the CERN LHC experiments are operated with gas mixtures based on R-134a, i-C4H10 and SF6. R-134a and SF6 are potent greenhouse gases, known for their high Global Warming Potential, and are therefore subject to decreasing availability due to the European regulation on F-gases.
A mid-term solution was identified in reducing the use of R-134a by diluting the standard gas mixture with 30% CO2. However, to keep the detector performance stable, the SF6 concentration has to be increased from 0.3% to 0.5% or 1%.
This contribution shows the performance of RPCs operated with alternatives to SF6, in particular with two gases from the family of chlorinated hydrofluoroolefins: R-1233zd and R-1224yd.
The performance is shown using the standard CMS gas mixture as a reference, as well as the ATLAS RPC gas mixture containing 30% CO2.
The detectors were operated in laboratory conditions with cosmic muons for gas mixture tuning. Once suitable gas mixtures were found, the RPCs were tested at CERN’s Gamma Irradiation Facility, where a gamma source provided background conditions similar to those expected at the High-Luminosity LHC, and a muon beam allowed the detection efficiency to be evaluated.
The increased concentration of isobutane and the use of reclaimed R-134a with RPC operated in laboratory condition is also investigated, and preliminary results will be presented.

Speaker: Gianluca Rigoletti (CERN)

11:10 Towards SF₆-free RPC operation: first results from the RPC ECOGas@GIF++ Collaboration

Gaseous detectors play a key role in particle physics, yet their operation often relies on fluorinated gases with very high Global Warming Potential. In particular, Resistive Plate Chambers (RPCs) operated in avalanche mode typically employ high-performance gas mixtures containing high-GWP components such as C₂H₂F₄ and SF₆.
With increasing environmental concerns and progressively tighter regulations, the reduction or replacement of these gases has become a central challenge. Within the RPC ECOGas@GIF++ Collaboration, a comprehensive R&D program has investigated alternatives to C₂H₂F₄, establishing HFO1234ze-based mixtures as viable candidates for RPC operation in particular under middle-high rate conditions.
Building on these results, a new phase of studies is now focused on the identification of eco-compatible substitutes for SF₆, which plays a crucial role in streamer suppression. This effort includes a re-optimization of the gas mixture composition as well as dedicated modifications of the experimental setup, aimed at maintaining stable detector operation and performance in the absence of SF₆. Several mixture configurations are currently under investigation at the CERN GIF++ facility.
This contribution presents the first results of this new R&D phase, including measurements from the 2026 beam tests, and discusses the prospects for fully SF₆-free RPC operation.

Speaker: Luca Quaglia (Universita e INFN Torino (IT))

11:30 Study of ATLAS RPC system performance for increasingly stable and sustainable operation in HL-LHC runs

The trigger system in the barrel region of the ATLAS experiment at CERN relies on about 3700 2 mm gas-gap Resistive Plate Chambers (RPCs), which will be upgraded during Long Shutdown 3 with an additional system of about 1000 new 1 mm gas-gap RPCs to be installed in the muon Inner Barrel. Since 2008 and until 2023, these detectors have been operated in avalanche mode with a gas mixture based on R134a, i-C₄H₁₀, and SF₆. While this mixture has provided relatively stable operation and good performance, it presents two major limitations for the future: the increasing difficulty in procuring R134a and SF₆ due to their high global warming potential (GWP), and the production of chemically aggressive fluoride radicals that negatively affect RPC longevity. Indeed, since 2023, when the LHC reached a stable luminosity of 2 × 10^34 cm^-2 s^-1, this effect has become evident.

To address both issues, a stepwise strategy for reducing fluorinated gases has been pursued since 2022, targeting both environmental impact and detector ageing. Following extensive validation at the Gamma Irradiation Facility (GIF++), a first new mixture, replacing 30% of the R134a with CO₂, was adopted by ATLAS for the 2024 run, achieving a ~17% GWP reduction while preserving performance. A further optimization in 2025 consisted of reducing the SF₆ fraction, leading to a total GWP reduction of about 25%. In both cases, a significant and increasing reduction of the ageing impact was measured on the ATLAS RPCs during the 2024 and 2025 runs, respectively.

The ongoing validation activity is focused on replacing SF₆ with an alternative component, aiming to achieve a total GWP reduction of about 36% with respect to the standard mixture. A dedicated long-term ageing campaign has started to validate the compatibility of the new mixture with the expected Run 4 luminosity of up to 7.5 × 10^34 cm^-2 s^-1 and beyond.

A recent spinoff study presents an even more ambitious perspective, based on the experimental observation that the efficiency of RPCs decreases less than expected at higher CO₂ concentrations, opening the possibility of a further substantial reduction in GWP while increasing the resilience of the RPCs.

Speaker: Sinem Simsek (Istinye University (TR))

11:50 → 13:50 Lunch

13:50 → 14:30 Satellite Seminar

Auditorium 111 (UERJ/Maracanã)

Convener: Eliza Melo (Universidade do Estado do Rio de Janeiro (BR))

14:30 → 15:10 Alternative Mixtures and Longevity

Auditorium 111 (UERJ/Maracanã)

This session is dedicated to Eco-gas R&D and long-term operation: low-GWP mixtures, gas systems/recirculation, irradiation and aging studies, impurities, and mitigation strategies.

Convener: Luiz Mundim (Universidade do Estado do Rio de Janeiro (BR))

14:30 Studies on ALICE MID RPC characteristics after prolonged operation and/or storage

The first batch of ALICE MID Resistive Plate Chambers was produced in 2005, more than twenty years ago. Since then, these gas gaps have either been operated in the ALICE MID or stored under controlled temperature conditions as spares.

In 2022, two MID gas gaps were replaced due to increasing dark currents and were subsequently studied with the ALICE RPC cosmic-ray test station in Torino. The aim was to assess their performance and working parameters after more than ten years of operation. In addition, two RPCs stored as spares since 2008 were tested using the same setup, in order to investigate the effects of long-term storage. The detectors initially showed very high dark currents, which were significantly reduced through a long conditioning process.

This presentation will report the results of these studies. Possible explanations for the initial high dark currents, as well as for the effectiveness of the conditioning process, will also be discussed.

Speaker: Alessandro Ferretti (Universita e INFN Torino (IT))

14:50 Latest results from Longevity Studies of CMS RPC Chambers towards HL-LHC Operation

The Compact Muon Solenoid (CMS) Resistive Plate Chamber (RPC) system has operated successfully during the LHC Run 1, Run 2, and Run 3 data-taking periods. During the High-Luminosity Large Hadron Collider (HL-LHC) phase, the instantaneous luminosity is expected to increase by up to a factor of five with respect to the nominal LHC conditions, leading to higher background rates and harsher operating conditions for the CMS RPC detectors. Such conditions could affect detector performance and potentially induce non-recoverable aging effects. To evaluate the long-term behaviour and robustness of the RPC system under HL-LHC conditions, a dedicated longevity test has been carried out at the CERN Gamma Irradiation Facility. In this program, four spare RPC chambers (two RE2 and two RE4) have been exposed to intense gamma irradiation in order to reproduce the expected HL-LHC environment. The irradiation campaign has reached the expected integrated charge for HL-LHC operation for the RE2 and RE4 chambers, respectively, including the expected safety factor. During the test, the main detector performance parameters have been continuously monitored as a function of the accumulated integrated charge. The results obtained from the irradiation studies will be presented.

Speaker: Reham Aly (Politecnico - Universita e INFN, Bari (IT))

15:10 → 15:20 Conference Photo

11th-floor lobby, Block F, near Auditorium 111

15:20 → 15:50 Poster session

11th-floor lobby, Block F, near Auditorium 111

Conveners: Kevin Mota Amarilo (Universidade do Estado do Rio de Janeiro (BR)), Mapse Barroso Ferreira Filho (Universidade do Estado do Rio de Janeiro (BR))

15:20 Study of CMS RPC signal shape parameters by using HFO1233ZD gas mixture

Widely adopted in high-energy physics experiments, Resistive Plate Chambers (RPCs) face a significant challenge due to new regulations that severely limit allowable greenhouse gas emissions — including those typically used in RPC operation. As a result, finding a mixture with low global warming potential has become a priority for the gas detector community. In this context, we present an investigation of iRPC waveforms obtained during a muon test beam at CERN’s Gamma Irradiation Facility conducted in 2026. Our approach incorporates waveform analysis and machine-learning algorithms to classify signals from iRPC chambers operating on an HFO1233ZD-based mixture, as a candidate to replace SF6. The machine learning model aims to improve the understanding of discharge mechanisms in candidate gases and to enrich insights from analytical methods

Speaker: Dalmo Da Silva Dalto (Universidade do Estado do Rio de Janeiro (BR))

15:30 A Study of Muon Production Using Electron Beams and RPC Detection Techniques

Muon detection is an important aspect of modern high energy physics experiments due to the strong penetration capability of muons compared with other secondary particles. In this work, a simulation study was carried out using the FLUKA Monte Carlo package to investigate the production of muons generated by the interaction of electron beams with different target materials and target thicknesses. The simulation was used to evaluate the yields of secondary particles, including $\mu^{+}$, $\mu^{ -}$, electrons, positrons, and gamma particles, in order to study the dependence of particle production on the target configuration and to identify conditions that enhance muon generation while reducing background radiation. Since electromagnetic interactions inside the target produce a large amount of unwanted particles, a concrete shielding system was implemented downstream of the target to suppress the background flux. The obtained results showed that the shielding was highly effective in removing electrons, positrons, and gamma particles, whereas muons were able to traverse the shielding because of their high penetration capability.

To investigate the detector response to the transmitted muons, an RPC prototype geometry was included in the simulation setup. The energy spectra and spatial hit distributions on the RPC detector plane were analyzed to study the expected muon response and detection performance. The results demonstrate that the combination of shielding techniques with RPC based detection systems provides a possible method for selective muon detection in electron beam induced environments, making this approach promising for future beam test experiments and RPC detector studies.

Speaker: Tahany Elhussieny Abdelhameid (ENHEP Egyptian Network of High Energy Physics (EG))

15:30 A Web-Based Data Acquisition System for Characterization of Particle Detectors

We present a modular data acquisition (DAQ) system developed for the automated characterization of particle detectors at the Nuclear and Particle Physics Laboratory (LFNP). The system integrates control of CAEN high-voltage power supplies with a finite-state machine (FSM) engine to orchestrate scans across multiple detector channels.

The architecture comprises three services: a web-based frontend, a REST API backend with a relational database, and an asynchronous DAQ engine. Each scan runs as an independent FSM instance. Scans can be started, stopped, paused, and resumed remotely, and multiple scans can run concurrently on independent detector channels.

The system is deployed via Docker containers being reproducible across many systems. The DAQ system is currently validated in offline testing and being prepared for integration with CAEN hardware.

Speaker: Kevin Mota Amarilo (Universidade do Estado do Rio de Janeiro (BR))

15:30 Aging studies of CMS Improved Resistive Plate Chambers through spectroscopic and microscopic characterization of irradiated HPL

The CMS Improved Resistive Plate Chambers (iRPCs) are a key component of the muon detection system for operation during the High-Luminosity LHC era. Their long-term performance depends on the stability of the high pressure laminate (HPL) electrodes. Based on previous studies of iRPC aging performed at the CERN Gamma Irradiation Facility (GIF++), this work investigates the microscopic and chemical modifications induced in irradiated HPL samples and their possible connection to detector degradation. Samples extracted from linseed-oil-coated HPL electrodes exposed to gamma irradiation were analyzed using complementary diagnostic techniques, including Raman spectroscopy, photoluminescence, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The combined results indicate significant differences between irradiated and non-irradiated samples, suggesting the formation of radiation-induced defects and chemical transformations in the HPL surface layer. In particular, the observation of fluorine-containing deposits and localized structural degradation supports models relating detector aging to interactions between radiation products, gas by-products and electrode materials.

Speaker: Mapse Barroso Ferreira Filho (Universidade do Estado do Rio de Janeiro (BR))

15:30 An Online Track Reconstruction and Monitoring System for MRPC Cosmic-Ray Detectors Based on CERN ROOT

We present an online monitoring and track reconstruction system developed for a multi-detector MRPC (Multi-gap Resistive Plate Chamber) cosmic-ray test platform. Built upon CERN ROOT and deployed in a Linux environment, the system enables simultaneous performance evaluation of multiple MRPC detectors. It performs real-time track fitting using hit information, allowing users to add or remove detector modules flexibly according to experimental configurations. The graphical interface displays hit positions and firing patterns on each detector, facilitating rapid diagnostics of detector status and data quality. The software employs a modular architecture that supports both continuous data acquisition and offline replay, with online histogram updates and alarm functions for abnormal channels. Tested with a telescope of six MRPCs, the system achieves a spatial resolution better than 1 mm and demonstrates stable operation over long runs. This tool significantly improves the efficiency of detector commissioning and cosmic-ray muon tracking, and it is readily adaptable to other resistive-plate chamber arrays for future RPC experiments.

Speaker: Dongdong Hu (University of Science and Technology of China)

15:30 An Optimized Algorithm for Determining CMS RPC HV Channel Working Points

The muon system of the Compact Muon Solenoid (CMS) comprises several gaseous detectors, including Resistive Plate Chambers (RPCs). Each data-taking year, a high-voltage (HV) scan is performed to ensure proper chamber operation and determine the optimal operating voltage of the RPCs. A new algorithm is proposed for determining the HV channel working points by scanning a range of voltages and selecting the optimal value that provides an efficiency and cluster size within the requirements for all detector modules connected to this HV channel. The algorithm was tested using 2025 and 2026 HV Scan calibration data and compared with the standard procedure. The results show increased efficiency with respect to the standard algorithm while restricting cluster size to stay reasonably low. Although differences in operating voltage are observed for some channels compared to the standard procedure, the new method offers a more precise way to determine the working point by maximizing the number of detector modules within a channel satisfying the efficiency and cluster size requirements.

Speaker: Mihaela Pencheva Pehlivanova (University of Sofia - St. Kliment Ohridski (BG))

15:30 CMS RPC system consolidation and upgrade for the LHC Phase-II programme

This poster presents the efforts to boost the performance and the reliability of the Resistive Plate Chambers (RPC) of the muon system of the Compact Muon Solenoid (CMS) experiment. The focus is on both the maintenance of the existing RPC chambers and the installation of the improved RPC detectors (iRPC) for the Phase-II upgrade. The RPC system consolidation is based on the standard maintenance of the present power system and the gas leak repair, which would allow powering back on the leaking chambers. The installation of 72 new improved RPC detectors, in addition to the upgrade of the power system, is ongoing as part of the new RPC Phase-II upgrade programme. At the end of 2024, 36 iRPC chambers were installed and are already under commissioning in the CMS experiment. This poster offers valuable insights into the maintenance procedures of the RPC detector and the activities crucial for the success of the ongoing and Phase-II data taking of CMS.

Speaker: Katherine Maslova (UERJ/CERN)

15:30 CMS-RPC Timing Resolution Evolution Under the Longevity Campaign

The aging process is one of the main concerns when operating Resistive Plate Chambers (RPCs) in high-luminosity, long-term detector experiments such as the Compact Muon Solenoid (CMS). Since 2010, the CMS experiment has collected about 500 fb⁻¹ of pp collision data, while the expectation for the HL-LHC is to collect more than 3000 fb⁻¹. To ensure reliable operation throughout this period, the CMS-RPC system has undergone an extensive longevity campaign at the Gamma Irradiation Facility (GIF++). The irradiation campaign has delivered an integrated charge equivalent to the full HL-LHC expectation for the RE2 chambers and 63% of the expected value for the RE4 chambers, with a safety factor of three included in the estimate. RPCs are known for their excellent timing resolution, which is an important component of the CMS muon trigger system. This work investigates the evolution of the RPC timing resolution throughout the longevity campaign for the RE2 and RE4 chambers.

Speaker: Mauricio Thiel (Universidade do Estado do Rio de Janeiro (BR))

15:30 Composition Analysis of Commercial Tetrafluoroethane Available to Local RPC Laboratories

Resistive Plate Chambers are one of the most used types of particle detectors in High Energy Physics since the 1980s. They offer advantages such as good time resolution and high-rate capability. They can be assembled using simple and cost-effective materials and gas mixtures, such as tetrafluoroethane. However, impurities in the gas can distort the signals or even damage the detector shortening its lifetime. In this study, the composition of different commercially available tetrafluoroethane supplied by different manufacturers was investigated using an ambient-pressure quadrupole mass spectrometer with ppm-level sensitivity. The experimental setup allows the direct analysis of gas composition without prior sample preparation, enabling the identification of residual atmospheric contaminants, moisture and trace molecular species over a mass range extending to 200 amu. The measurements were performed under controlled gas-flow conditions, providing a systematic comparison of the different commercial products available to RPC laboratories. Beyond the comparison of gas purity among different suppliers, this work provides a detailed interpretation of the characteristic fragmentation pattern of tetrafluoroethane under electron-impact ionization. Since similar ionization mechanisms govern the interaction of energetic electrons with gas molecules in gaseous detectors, the identified fragmentation pathways provide a valuable reference for the interpretation of molecular species and decomposition products generated during detector operation and aging studies.

Speaker: Willian Da Silva (Universidade de Sao Paulo (BR))

15:30 Development and Validation of a Low-Cost Volume-Based Gas Mixing System for CMS Resistive plate chambers

Gas mixtures for particle detectors are conventionally prepared using mass flow controllers, which can be costly. This work presents the development of a low-cost volume-based gas mixing system that uses peristaltic pumps to produce gas mixtures through volumetric dosing. The effectiveness of the system was evaluated using gas chromatography by comparing the composition of the produced mixture with that of a commercial pre-mixed gas bottle. The mix gas (standard CMS RPC mixture) was then supplied to a RPC detector to assess its operational performance and verify the suitability of the produced mixture. This poster presents the system design, calibration procedure, and detector performance results, demonstrating a cost-effective alternative for detector gas mixing applications.

Speaker: Mahdi Majeed S. Almubarak (American University of Bahrain (BH))

15:30 Development and Validation of a Thermal Protection Circuit Breaker for the CMS iRPC Front-End Electronics

A dedicated electronic circuit breaker has been developed to provide autonomous thermal protection for the front-end electronics of the CMS Improved Resistive Plate Chamber (iRPC) system at the High-Luminosity LHC. The board continuously monitors the temperature near the front-end ASICs using a PT100 sensor and disconnects the 4 V power supply whenever a predefined safety threshold is exceeded. To ensure high reliability, the protection logic adopts a redundant, fail-safe architecture based on a simple analog circuit with MOSFET switches, without the use of digital processing logic. The board was validated through laboratory measurements and tested with fully instrumented iRPC chambers at CERN on cosmic stand and at the Gamma Irradiation Facility (GIF++). The results confirmed stable operation and no measurable impact on detector performance (noise, efficiency, working point). This poster presents the design, implementation and experimental validation of the circuit breaker, demonstrating its effectiveness as a reliable thermal protection system for the CMS RPC front-end electronics while remaining fully transparent to detector performance.

Speaker: Mehar Ali Shah (Universidad Iberoamericana (MX))

15:30 Development of a Closed-Loop Gas Regeneration System for RPC Detectors

Resistive Plate Chambers require a continuous supply of suitable operating gas to ensure stable and reliable detector performance. However, the use and disposal of RPC gases represent an important environmental and operational challenge, particularly in laboratories and experimental systems where long-term detector operation is required. In this context, the development of gas regeneration and reuse systems is an applied solution with strong potential to reduce gas consumption, operational costs, and environmental impact.

This work presents the development of a closed-loop gas regeneration system for RPC detectors at the Neusa Amato RPC Laboratory of CBPF. The system is designed to collect the gas leaving the RPC, temporarily store it in a dedicated gas bag, and automatically transfer it to a regeneration unit. After regeneration, the gas is returned to the reservoir and becomes available again for detector operation. This architecture avoids direct coupling between the RPC outlet and the regeneration machine, preventing unwanted pressure effects on the detector.

The system integrates pressure monitoring, flow switching, electrovalves, safety elements, and microcontroller-based automation to control the gas flow cycle. The control logic detects the state of the gas bag, manages the transfer of the used gas to the regeneration unit, and coordinates the return of the regenerated gas to the reservoir under controlled conditions.

The poster will present the concept, closed-loop architecture, main components, control strategy, and current development status of the system. This work contributes to the development of practical and sustainable infrastructure for RPC operation, providing a flexible platform for gas reuse and future long-term validation studies.

Speaker: Luis Miguel Domingues Mendes (CBPF)

15:30 Development of RPC Detector Components with Low-Cost Alternative Materials

Resistive Plate Chambers (RPCs) are gas-based particle detectors widely used in High Energy Physics experiments such as CMS and ATLAS, as well as in several other particle physics experiments since the 1980s. Their main advantages are the relatively low cost of covering large areas, compared with non-gas-based detectors, and the very good timing resolution compared with other gas-based detectors. The detector consists of two parallel plates (electrodes), whose external surfaces are coated with a graphite layer connected to a potential difference, producing an electric field of the order of 5 kV/mm. Both the electrodes and the graphite coating must have high and well-controlled resistivity; for the first, glass or bakelite is usually used. The gap between the parallel plates is filled with a gas with high ionization potential, which triggers an electron avalanche when a charged particle passes through the detector. In this work, we explore different techniques and materials to produce components for this type of detector and overcome the limitations of conventional materials, such as Bakelite, which exhibits poor industrial reproducibility and modest mechanical properties such as a lack of rigidity over large areas, applying additive manufacturing techniques to the creation of new 3D-printed frames. In addition to the development of graphite-infused ABS mixtures, as well as graphite powder mixed with commercial acrylic ink for the resistive layer by a centrifugal coating process, we aim to explore alternatives to the manufacturing processes of RPCs and achieve typical operating ranges (from 10⁹ to 10¹² Ω·cm) with greater design flexibility. These painting and manufacturing techniques for the electrodes can open new configuration possibilities due to their controlled resistivity and the ease of producing layers with controlled thickness.

Speaker: Gabriel Campanelli (UERJ)

15:30 Extending Garfield++ for Efficient Multi-Stack MRPC Simulation with Space-Charge Effects and Differential Readout

We present a simulation framework for avalanche development, signal formation, and timing studies in a multi-stack resistive plate chamber (MRPC). The detector model has four stacks of six gas gaps and five strip-readout planes.

Cosmic-ray muon tracks generated with CRY are supplied to TrackHeed to simulate primary ionization in the detector gas. Early avalanches are treated with microscopic electron transport, after which the electrons are transferred to a grid-based calculation including diffusion and space-charge effects. Weighting potentials for readout strips are calculated with a two-dimensional neBEM model and imported as interpolation maps. A reference-strip solution is translated to the remaining strips to avoid repeated field calculations. Targeted refinements were introduced in Garfield++ to preserve disconnected strip boundaries in neBEM calculations and to consistently initialize transport properties for gas gaps not populated by the initial avalanche.

Signals from corresponding strips on the five readout planes are propagated to a common reference plane and combined to construct the differential response. Leading-edge crossing times and time-over-threshold values are then extracted and used for time-walk correction. Preliminary studies demonstrate physically consistent signal formation and enable systematic studies of thresholds, cluster size, efficiency, and timing.

Speaker: Mr Yiding Zhao (USTC(University of Science and Technology of China))

15:30 First Simulation Studies of iRPC Reconstruction in CMS

The CMS experiment is upgrading the muon system for High-Luminosity LHC (HL-LHC). Improved Resistive Plate Chambers (iRPCs) will be installed in the endcap stations RE3 and RE4. Compared to conventional RPCs, iRPC has better timing performance because it uses dual TDC channels with bunch-crossing, sub-bunch-crossing, and fine-time information, giving much finer time resolution than the 25 ns bins of the current RPC system. This study presents a first check of iRPC reconstruction using CMS simulation. iRPC signals are clustered and used to build reconstructed hits with local position and time. To study the reconstruction quality, each hit is compared with the simulated ones that produced the fired strips in the same cluster. The performance is studied using local x and y residuals, cluster size, bunch crossing, the number of simulated tracks contributing to each reconstructed hit and basic time-related variables. These results give information about spatial resolution, noise contribution and the possible use of improved iRPC timing. This work is one of the first studies of iRPC reconstruction hits in CMS and can be useful for monitoring iRPC performance before HL-LHC data-taking.

Speaker: Juhee Song (Vrije Universiteit Brussel (BE))

15:30 Long-Term Evolution of the CMS RPC Integrated Charge and Projections for the HL-LHC Era

The Resistive Plate Chamber (RPC) system of the CMS experiment has been operating successfully since the beginning of LHC data taking. The prolonged exposure to radiation backgrounds throughout Run 1, Run 2, and Run 3 provides a unique opportunity to assess the long-term behavior of the CMS RPC detectors and to evaluate their expected performance throughout the High-Luminosity LHC (HL-LHC) programme. Since last analysis performed in 2017, the CMS RPC system has accumulated approximately eight additional years of operation, more than doubling the dataset available for charge accumulation studies. To support long-term monitoring, a dedicated automation framework has been developed and deployed. The framework retrieves detector current information, computes the integrated charge contribution every four hours, and automatically stores the accumulated charge of each chamber on a daily basis. This approach provides a complete and continuously updated chamber-by-chamber history of the detector exposure and significantly simplifies long-term performance studies. The enlarged dataset enables improved data-driven extrapolations of the accumulated charge expected at an integrated luminosity of 3000 fb^(-1). The extrapolations are obtained from fits to the measured charge evolution and are used to identify the detector regions expected to receive the highest exposure during HL-LHC operation. In addition, the study presents the current accumulated charge measured throughout the CMS RPC system and provides detailed radial and azimuthal charge distributions for all chambers. The measured charge evolution and HL-LHC projections are being discussed.

Speaker: Jose Antonio Reyes Vega (Universidad de los Andes (CO))

15:30 Low-loss strip-merging extensions for the RPC chambers

The COMET experiment at J-PARC searches for the charged-lepton-flavour-
violating process of coherent muon-to-electron conversion in a muonic atom, $\mu^- N \to e^- N$, with a target single-event sensitivity of $\mathcal{O}(10^{-15})$ during Phase I, expected to start in 2028. Low-energy negative muons are produced by a high-intensity proton beam colliding with an upstream target and are transported downstream to the stopping target. The primary signal studied during Phase I is a track reconstructed in a Cylindrical Drift Chamber, produced by an electron with an energy equal to the muon mass.

The main background capable of mimicking this signal arises from muons produced in cosmic-ray showers. To identify and reject these muons, COMET employs a Cosmic Ray Veto (CRV) system based, in particular, on RPC chambers. The most challenging region of the CRV is the front area, which is especially exposed to neutron and electromagnetic backgrounds originating from the up-stream target. Simulations indicate that background hit rates can reach up to $2\rm~kHz/cm^2$, significantly complicating the identification of cosmic muons. We proposed to equip this area with improved RPC chambers designed for the Phase II upgrade of the CMS experiment at CERN. In these chambers, pickup strips embedded in large PCBs are read out from both ends by sophisticated Front-End Boards (FEBs) hosting TDCs implemented in FPGAs. The FEBs represent the largest cost component of the project. To reduce costs, we propose a modular solution: using final readout PCBs with fine segmentation from the outset, while temporarily merging adjacent strips in pairs via low-cost extension boards. This allows the FEB production to be split into two phases. However, designing extension boards capable of merging strips without degrading signal integrity is non-trivial due to the low signal amplitudes, the impulsive nature of RPC signals (as opposed to sinusoidal RF signals), ambient noise, and impedance mismatches that can generate reflections at the merging points.
In this poster, we present a proof of concept for RPC signal merging, including the design, production, and certification of the extension boards.

Speaker: Maxime Gouzevitch (Centre National de la Recherche Scientifique (FR))

15:30 Monte Carlo Study of CO$_2$-Based, TFE- and SF$_6$-Free Gas Mixtures for Resistive Plate Chambers

Resistive Plate Chambers (RPCs) traditionally operate with a gas mixture based on C$_2$H$_2$F$_4$ (TFE) and SF$_6$, both high-GWP greenhouse gases facing growing regulatory and supply restrictions. C$_3$H$_2$F$_4$ (F-HFO) diluted with CO$_2$ has been proposed as a lower-GWP substitute for TFE, while its chlorinated variant, C$_3$H$_2$ClF$_3$ (Cl-HFO), has separately been explored as a streamer suppressor replacing SF$_6$. However, most studied mixtures still retain either TFE or SF$_6$. This work targets mixtures free of both.

We present a preliminary Monte Carlo study, based on Geant4 and Garfield++ simulations, of two CO$_2$-based mixture families. The first revisits CO$_2$/F-HFO/i-C$_4$H$_{10}$/Cl-HFO, exploring new CO$_2$:F-HFO ratios not yet covered in the literature. The second proposes an untested quaternary mixture, Ar/CO$_2$/N$_2$/Cl-HFO, replacing the fluorinated fraction with an Ar-based matrix. In both cases, Cl-HFO is kept in minority concentration as the streamer-suppressing component replacing SF$_6$.

For both mixtures, Townsend and attachment coefficients, gas gain, drift velocity, efficiency and streamer probability are computed versus applied field and compared to the standard mixture. Results address operating voltage shift, plateau width, and whether Cl-HFO sustains streamer suppression without SF$_6$ in a non-fluorinated base, framing open questions for future experimental validation.

Speakers: Guilherme Lickel (UNICAMP), Edmilson Manganote (CBPF and UNICAMP)

15:30 Neural Network-Based Prediction of CMS RPC Efficiency with Alternative Gas Mixtures

Resistive Plate Chamber (RPC) detectors are widely used in major CERN experiments as muon trigger systems thanks to their excellent time resolution. However, the gas mixtures currently employed in RPCs contain greenhouse gases, such as C2H2F4 (R134a) and SF6, with Global Warming Potential (GWP) of 1430 and 22800 respectively, which contribute significantly to environmental emissions. During LHC Run 2, approximately 85% of the emissions from particle detectors originated from RPC gas leaks. For this reason, several environmentally friendly alternative gas mixtures have been investigated. Building on these efforts, this work aims to develop a neural-network-based model capable of predicting RPC efficiency curves for low-impact gas mixtures. A feed-forward neural network with two hidden layers is trained to predict the three parameters of the sigmoid efficiency curve, maximum efficiency, slope, and HV at 50% efficiency, as a function of the gas mixture composition. The model is trained on experimental data collected at the CERN Gamma Irradiation Facility (GIF++) using 16 alternative gas mixtures based on HFO and CO2 as R134a substitutes, and Novec 4710 as an SF6 alternative. Model performance is evaluated using Leave-One-Out cross-validation. Preliminary results show good agreement between model predictions and experimental data when the gas composition lies within the parameter space covered by the training dataset. The goal is to extend the model's predictive power to mixtures with arbitrary combinations of known components, as well as new gas components not included in the training data, thus providing a versatile tool for the study and optimization of sustainable RPC operation. This tool is particularly relevant in view of the upcoming Long Shutdown 3, during which experimental measurements at GIF++ will not be possible, making predictive modelling a key asset for advancing the search for sustainable gas mixtures. This poster will present the current status of the project.

Speaker: Giulia Giannandrea (Pavia University and INFN (IT))

15:30 Performance Characterization of CMS iRPC Detectors at GIF++

The improved Resistive Plate Chamber (iRPC) is a newly introduced detector in the CMS Phase-II Upgrade, designed to enhance muon detection efficiency in the forward region under the challenging conditions of the High-Luminosity Large Hadron Collider (HL-LHC). The detector was developed to operate at particle rates of up to 2 kHz/cm², corresponding to the expected background levels with an additional safety factor of three, while maintaining a detection efficiency above 95%. To validate their performance, iRPC detectors were tested at the Gamma Irradiation Facility (GIF++) at the European Organization for Nuclear Research (CERN). GIF++ combines a high-intensity (^{137})Cs gamma source with high-energy muon beams from the Super Proton Synchrotron, providing a controlled irradiation environment that closely reproduces the conditions expected in CMS during HL-LHC operation. The results presented here were collected during the 2025 and 2026 test campaigns. Efficiency measurements were performed for various gamma-source attenuation settings, corresponding to different background radiation levels. The detectors demonstrated excellent performance, maintaining high detection efficiency and stable operation across the full range of irradiation conditions investigated.

Speaker: Silas Santos De Jesus (Universidade do Estado do Rio de Janeiro (BR))

15:30 Performance study of the CMS RPC detector using the Tag-and-Probe method in LHC Run 3

The CMS experiment is collecting proton-proton collision data at a center-of-mass energy of 13.6 TeV during LHC Run 3. Resistive Plate Chambers (RPCs) are an important component of the CMS muon system, providing fast timing information for the muon trigger and contributing to muon reconstruction. This study presents an updated evaluation of the CMS RPC detector performance using Run 3 data, including additional data-taking periods beyond those previously reported. The performance is measured with the Tag-and-Probe method using Z boson decays into two muons. In this method, one well-reconstructed muon is used as the tag, while the other muon is used as the probe. The probe muon is extrapolated to the RPC detector and the RPC response is evaluated by matching detector hits to the extrapolated trajectory. The RPC detector performance is characterized through efficiency measurements and complementary response-related observables. The study considers the evolution of the detector performance with accumulated data and its dependence on probe-muon properties. This updated measurement provides additional information on the RPC detector response during the extended Run 3 data-taking period. The study contributes to the performance monitoring of the CMS RPC system and to the continued validation of its role in muon triggering and reconstruction.

Speaker: Jongwon Shin (Kyung Hee University (KR))

15:30 Quality Control Protocols of CMS iRPC Chambers for Phase-II CMS Muon System Upgrade

In preparation for the Phase-II upgrade for the High-Luminosity LHC program, out of 72 improved Resistive Plate Chambers (iRPC) 36 are already installed and remaining 36 are to be installed in the third and fourth endcap disks of the Compact Muon Solenoid (CMS) during LS3. This new generation of RPC detectors will operate in a low-angle momentum (extending RPC coverage from pseudorapidity |η|= 1.9 to 2.4), in a high radiation environment, and will bring a better space and time resolution for this challenging region. To ensure proper performance, iRPC chambers undergo a series of quality control (QC) tests at each stage of the assembly chain. In this poster we present the different QC stages and discuss test results for the full production of CMS iRPCs.

Speaker: Anas Idriss Laayouni El Oudghiri (University of Dundee (GB))

15:30 Simulation of F⁻ and HF Transport in the RPC Gas Flow

Resistive Plate Chambers (RPCs) are vital gaseous detectors used for precise particle detection and fast triggering in experiments like the Compact Muon Solenoid (CMS) at the LHC. Under high voltage (10 kV) and intense radiation, the standard gas mixture (95.2% $C_{2}H_{2}F_{4}$, 4.5% $i-C_{4}H_{10}$, 0.3% $SF_{6}$) undergoes molecular dissociation under electron avalanches. This cascade produces reactive fluorine radicals and ionic species, forming hydrogen fluoride (HF)—a corrosive neutral byproduct. Unlike ions, HF transport is decoupled from the electric field and behaves as a passive scalar driven by convective fluid dynamics and molecular diffusion within the thin-gap geometry.
Predicting HF accumulation is crucial for the upcoming LHC Phase-2 upgrade. This study presents a 3D physicochemical transport model of steady-state HF dispersion within an RPC segment. The fluid flow is resolved via incompressible Navier-Stokes equations, while chemical transport is governed by the advection-diffusion equation, using molecular diffusivities from Chapman-Enskog binary collision theory. The system is discretized via a mixed Taylor-Hood (P2-P1) Finite Element Method (FEM) for the flow and second-order Lagrangian elements (P2) for the scalar, implemented using the Gridap library in Julia.
Simulations at an operational regime (Re = 11.41) reveal a monotonic concentration gradient, identifying localized stagnation regions prone to degradation. Mass balance analysis shows that most HF is removed via diffusive fluxes to the walls due to the high surface-to-volume ratio. These results demonstrate order-of-magnitude consistency with experimental data from the Gamma Irradiation Facility (GIF++), validating the model for geometric optimization of next-generation RPCs.

Speaker: Mauricio Thiel (Universidade do Estado do Rio de Janeiro (BR))

15:30 Studies of F- production in the ALICE MID RPC detectors during LHC Run 3

The ALICE Muon IDentification (MID) system consists of 72 single-gap Resistive Plate Chambers (RPC), operated with a gas mixture composed of: 89.7% C2H2F4, 10% i-C4H10 and 0.3% SF6, with a 37% relative humidity content. To reduce gas consumption and emissions, the MID gas system is operated in closed loop mode with a recirculation fraction of 88%. The high concentration of fluorinated gases in the mixture, combined with the background radiation and the high voltage applied to the detectors, leads to the production of F- ions and F-based impurities. Among these, hydrofluoric acid is especially dangerous since it could lead to long-term deterioration of the detector or the gas system surfaces.

During the LHC Run 2, a preliminary setup was installed to monitor the formation of these impurities, successfully demonstrating their production as well as the capability of the purifying cartridges employed in the closed-loop gas system to trap them, further validating the operation of the gas system in recirculation mode.

During Long Shutdown 2, the set up was improved and commissioned at the restart of LHC Run 3. It now features a gas chromatograph to monitor the correct composition of the gas mixture and F-based impurities and an Ion Selective Electrode (ISE) station to quantify the F- concentration.
This contribution provides an overview of the production and accumulation of F- impurities within the MID system for the whole duration of the LHC Run 3, as well as a comparison to what was measured during LHC Run 2.

Speaker: Luca Quaglia (Universita e INFN Torino (IT))

15:30 The impact of the RPC system on the trigger primitives in CMS barrel region

High energy collisions in LHC produce an enormous number of particles and consequently a large quantity of electronic signals, which is a challenge for the The Compact Muon Solenoid (CMS). The increasing instantaneous luminosity of the LHC, i.e. HL-LHC, will be in the order of 2 x 10^34 cm^(-2)s^(-1). In that context, the CMS Level-1 (L1) trigger system rapidly processes raw information of the detector to efficiently select events containing interesting physics signatures. This raw information is named trigger primitives (TPs), which summarize detector hits into preliminary muon candidates. The Drift Tube (DT) system has a crucial role in providing spatial and temporal measurements for muon detection in the CMS barrel region |eta| < 1.2. In the DT system, the TPs are built through an algorithm named Analytical Method (AM). In AM, the final step, the timing information from Resistive Plate Chambers (RPCs), with superior timing resolution, is incorporated forming the so-called DT+RPC super-primitives. But the calculation used by the DT system is limited to evaluate the correct TP efficiency when the RPC system is working and the DT system is offline. To solve this problem, a collection in the simulation whose contents are RPC hits that can be related to muon from collisions can be used to check the correct RPC impact in TP efficiency. In addition, a proposal correction for RPC only segments is made by combining the two RPC layers, at the first and second stations (MB1 and MB2), to evaluate the reconstructed RPC time information correctly. Using simulated collision data with high pile-up conditions (average of 200 interactions per event), we demonstrate that these improvements offer robust performance enhancements for the CMS trigger system with the presence of the RPC system, ensuring more reliable identification and reconstruction of muon events in high-luminosity environments.

Speaker: Raphael Gomes De Souza (DFNAE - UERJ)

15:50 → 16:20 Coffee Break

11th-floor lobby, Block F, near Auditorium 111

16:20 → 18:00 Poster session

11th-floor lobby, Block F, near Auditorium 111

Conveners: Kevin Mota Amarilo (Universidade do Estado do Rio de Janeiro (BR)), Mapse Barroso Ferreira Filho (Universidade do Estado do Rio de Janeiro (BR))

Wednesday 16 September

08:00 → 08:50 Registration

Entry to auditorium 111 (UERJ/Maracanã)

08:50 → 09:20 Plenary session

Auditorium 111 (UERJ/Maracanã)

Convener: Kevin Mota Amarilo (Universidade do Estado do Rio de Janeiro (BR))

08:50 Sealed RPCs

Resistive Plate Chambers (RPCs), like most gaseous detectors, rely on gas purity to maintain stable performance. Gas degradation can occur due to leaks or permeability within the system, allowing atmospheric gases and/or humidity to enter. Additionally, molecular dissociation products generated during avalanche processes can also contribute to degradation over time. For this reason, permanent and large-scale detectors, in addition to introducing small amounts of fresh gas, use recirculation, purification and cleaning systems to maintain gas purity. These systems add significant complexity and cost to the detector.

The use of HFCs has become a major concern due to their high Global Warming Potential (GWP). This affects the main gas used in RPCs, tetrafluoroethane (C2H2F4). In fact, the European Union (EU) mandated the phase-out of HFCs in 2015. This presents serious challenges for existing RPC systems, and even more so for new systems, which will inevitably require alternative solutions.

A possible solution to the problem, from an environmental perspective is the replacement of these gases with others that have a much lower GWP, the so-called eco-friendly gases, with HFO-1234ze (C3H2F4) being the most promising alternative to tetrafluoroethane. However, using new eco-friendly gas mixtures would not imply a reduction of the complexity of the gas systems to be used.

Another possible solution would be to construct and operate RPCs without any gas supply, i.e. RPCs that contain gas but are hermetically sealed after construction, similar to the Geiger-Müller detectors. These devices were baptized as sealed RPCs (sRPC). It would mitigate the problem of HFCs phase-out by drastically minimizing the amount of gas used, thus reducing its environmental impact to negligible levels. It would also eliminate any dependence on complex gas systems, allowing the expansion of this type of technology towards Cosmic Ray (CR) experiments through the construction of large, high-performance arrays at low cost, which might replace the Cherenkov water tanks in remote and difficult-to-access locations typical of CR experiments.

This work presents a brief review of the initial steps in the development of this technology, highlighting some approaches that proved unsuccessful and others that led to its current state. The main adopted concepts are outlined.

We also review the results achieved so far, including the construction and operation of medium-sized (0.1 m²) and large-area (1 m²) detectors—primarily wide-multigap RPCs—as well as their long-term operation in the laboratory and within the framework of the SND@LHC experiment.

Finally, the next steps in the development of this technology are discussed.

Speaker: Mr Luis Lopes (Laboratório de Instrumentação e Física Experimental de Particulas)

09:20 → 10:00 Production and QA

Auditorium 111 (UERJ/Maracanã)

This session is dedicated to the detector production, assembly, industrialization, and QA/QC: procedures, acceptance tests, certification benches, reliability, logistics, and commissioning.

Convener: Kevin Mota Amarilo (Universidade do Estado do Rio de Janeiro (BR))

09:20 Improved Resistive Plate Chambers (iRPC) Mass Production and Performance for the CMS Phase-II Upgrade

The CMS muon system is being upgraded in preparation for the High-Luminosity LHC (HL-LHC), where significantly higher particle rates and radiation levels are expected. As part of this upgrade, 72 Improved Resistive Plate Chambers (iRPCs) in total will be installed in the RE3/1 and RE4/1 stations of the endcap muon system to maintain efficient muon triggering and reconstruction in the forward region. Following the completion of the detector design and qualification phase, the iRPC project has entered the final stages of mass production, assembly, and detector validation. A comprehensive quality assurance program has been established to guarantee detector performance and long-term operational stability. The overall performance was checked in the CERN Gamma Irradiation Facility to confirm our parameters with a safety factor 3. The quality control chain includes component validation, gas gap certification, chamber assembly tests, long-term high-voltage stability measurements, electronics verification, and cosmic-ray performance studies. This contribution presents an overview of the iRPC production campaign and summarizes the results obtained from the quality control procedures performed on the assembled chambers. Detector performance is evaluated through high-voltage scans and cosmic-ray measurements, including efficiency, working point determination, dark current behavior, and cluster size characterization. The distributions of these key performance indicators are analyzed for the full production sample and compared with the detector requirements established for HL-LHC operation. The results demonstrate a high level of uniformity among the produced chambers and confirm that the detectors satisfy the performance specifications required for installation in CMS. The status of the production and validation campaign is reviewed, together with the lessons learned from large-scale detector construction and testing. These results represent an important milestone toward the successful deployment of the iRPC system for the CMS Phase-II Upgrade.

Speaker: Eduardo Alves Coelho (Universidade do Estado do Rio de Janeiro (BR))

09:40 Quality Assurance and Quality Control of Gas Volumes for the Upgrade of the ATLAS RPCs for HL-LHC Operation

Gas-volume production is the first crucial step in the construction of Resistive Plate Chambers (RPCs), and Quality Assurance/Quality Control (QA/QC) at the production site is essential to ensure the high quality of the new RPC detectors to be installed in a large-scale experiment such as ATLAS. The production of the gas volumes for the upgrade of the Barrel Inner (BI) layer of the Muon Spectrometer started in 2023 and is still ongoing. During the QA/QC campaign, a few issues were identified, leading to improvements in the gas-volume production procedure. These improvements were successfully implemented. The results of the QA/QC tests performed on the BI gas volumes produced so far will be presented and discussed, together with the corresponding production improvements.

Speaker: Paolo Camarri (Università degli Studi di Roma "Tor Vergata" and INFN Roma Tor Vergata)

10:00 → 10:30 Coffee Break

11th-floor lobby, Block F, near Auditorium 111

10:30 → 11:10 Production and QA

Auditorium 111 (UERJ/Maracanã)

This session is dedicated to the detector production, assembly, industrialization, and QA/QC: procedures, acceptance tests, certification benches, reliability, logistics, and commissioning.

Convener: Joao Pinheiro (Universidade do Estado do Rio de Janeiro (BR))

10:30 Next generation MSMGRPCs for high interaction rate experiments

For the next generation high interaction rate experiments or for the upgrade at higher luminosities of the running ones, the development of detectors with high counting rate capabilities and aging effects mitigation is a paramount topic in the detector research field. Using a low resistivity glass (~10$^{10}$ $\Omega$cm) in the assembling of timing Multi-gap Resistive Plate Chambers (MSMGRPCs), a high detection efficiency and excellent time resolution was proved up to 30 kHz/cm${^2}$, with exposure over the whole active area. To address the mitigation of the aging effects, a new MSMGRPC architecture, based on discrete spacers (replacing the classical fishing line) and direct injection of the gas flow through the gas gaps, was developed. Dedicated aging investigations of the chambers with the new design assessed the long-term performance. Direct flow MSMGRPCs, with the same inner geometry but with different granularities (5 cm$^2$, 8.6 cm$^2$ and 17.6 cm$^2$ readout cell/strip size) were assembled and preliminary tested in the detector laboratory. Different types of discrete spacers were investigated. The performance of the chambers assembled with the chosen type of spacers, (time resolution, efficiency and hit position resolutions), was further tested in-beam, in real operation conditions with reaction products, at SIS18 accelerator of GSI Darmstadt. In addition, in order to accurately evaluate their performance in the detection of minimum ionizing particles, they were tested in a cosmic-ray tracking setup. Construction details of the chambers, in-beam and cosmic ray experimental setups together with the obtained results in terms of high detection efficiency, very good time resolution and two-dimensional position resolutions in both in-beam and cosmic rays tests will be presented. Moreover, the integration of direct flow MSMGRPCs with different granularities in a large area module for a modular implementation in large scale high energy experiments will be discussed.

Speaker: Mariana Petris (Horia Hulubei National Institute of Physics and Nuclear Engineering (RO))

10:50 The CMS RPC Construction Database: Lifecycle Traceability and Quality Assurance Across Multiple Detector Generations

The CMS RPC Construction Database was developed to support the large-scale production, certification, installation, and long-term traceability of Resistive Plate Chamber (RPC) detectors for the CMS experiment. Initially designed for the original CMS RPC construction campaign, the system has subsequently been extended and adapted to support multiple detector upgrade projects, providing a unified framework for detector production and quality assurance across several generations of RPC chambers. The database stores manufacturing data, quality-control measurements, and certification results for all chamber components and assemblies. Individual components are uniquely identified and associated with specific chambers, enabling complete traceability throughout the detector construction process. Following installation, each chamber remains linked to its physical location within the CMS detector, preserving the full production history of all removable components and ensuring compliance with detector documentation and traceability requirements. A hierarchical quality-control model is implemented, covering component certification, chamber assembly, chamber testing, and final validation before shipment and installation. In addition, quality certification is revalidated after each transportation step to verify that no damage or performance degradation has occurred during handling and logistics operations. The system is implemented using an Oracle relational database with a web interface developed in Oracle APEX. Dedicated procedures automate the evaluation of test results, chamber qualification, certification workflows, and installation readiness. Monitoring dashboards and production statistics provide real-time visualization of manufacturing progress and quality indicators during mass-production periods. Over multiple CMS RPC construction and upgrade campaigns, the database has proven to be a key tool for production management, quality assurance, detector traceability, and long-term preservation of provenance information throughout the detector lifecycle.

Speaker: Anton Dimitrov (University of Sofia - St. Kliment Ohridski (BG))

11:10 → 11:50 Satellite Seminar

Auditorium 111 (UERJ/Maracanã)

Convener: Joao Pinheiro (Universidade do Estado do Rio de Janeiro (BR))

11:10 Artificial Intelligence Applied to Test and Measurement Instruments: MXO AI Connect

The slides will be in English, and the presentation will be delivered in Portuguese.

Speaker Bibliography:
Graduated as a Technologist from Universidade Estácio de Sá, with multiple professional courses completed in Brazil,USA and Germany.

With over 27 years of experience in the test and measurement industry, has worked with the leading brands in the market throughout this time.

Began his career developing high-power switched-mode power supplies, and joined Rohde & Schwarz Brazil in 2012, taking on the responsibility of developing the brand’s oscilloscope market.

Since 2017, has been responsible for managing the distribution channels across the entire Brazilian territory.

Speaker: Mr Adriano Henrique Da Silva (Rohde & Schwarz)

11:50 → 13:50 Lunch

13:50 → 18:00 Free Time

18:00 → 20:00 Conference Dinner

Place: Terra Brasilis Restaurant

Date: September 16th at 7:00 - 9:00 PM local time

Local Address: Praça General Tiburcio S/N Urca, Rio de Janeiro, RJ, 22290-270 Brazil.

The conference dinner will be held at the Terra Brasilis restaurant in Praia Vermelha, next to the Pão de Açúcar cable car station. The RPC 2026 conference dinner will be one of the main social moments of the event, offering participants the opportunity to enjoy Brazilian cuisine in a relaxed atmosphere after the scientific sessions.

The dinner is planned as a three-hour service with a selection of appetizers, starters, main dishes, desserts, and drinks. The menu will highlight traditional Brazilian flavors, including options such as bolinho de feijoada, codfish bites, Brazilian pastries, tapioca cheese bites with pepper jelly, ceviche, moqueca, shrimp bobó, feijoada, Brazilian desserts, natural juices, craft beer, caipirinhas, and coffee.

More than a dinner, this will be an occasion to bring together participants, invited speakers, students, and collaborators, encouraging informal discussions and strengthening the RPC community during the conference week. Participants are strongly encouraged to reserve and pay for the Conference Dinner together with the registration fee through the event travel agency. For further information, please check the “Registration” section of this website.

Thursday 17 September

08:00 → 08:50 Registration

Entry to auditorium 111 (UERJ/Maracanã)

08:50 → 09:20 Plenary session

Auditorium 111 (UERJ/Maracanã)

Convener: Eduardo Alves Coelho (Centro Brasileiro de Pesquisas Fisicas (CBPF))

08:50 COMET experiment and opportunities

The COMET experiment at J-PARC searches for the charged-lepton-flavour-violating process of coherent muon-to-electron conversion in a muonic atom, $\mu^- N \to e^- N$, with a target single-event sensitivity of $\mathcal{O}(10^{-15})$ during Phase I, which is scheduled to begin in 2028. The experiment employs an 8 GeV bunched slow-extraction proton beam from the J-PARC Main Ring, which is transported via a dedicated beamline to the experimental facility. Superconducting solenoidal magnets efficiently capture and transport low-momentum muons to the stopping target. A suite of detector systems is being developed to identify signal electrons with high precision while suppressing background, including cosmic rays, using a dedicated Cosmic Ray Veto (CRV) system in which RPCs play a key role.

This contribution will present an overview of the current status of the COMET project, outline the roadmap toward Phase I operation, and highlight opportunities for collaboration and future contributions.

Speaker: Prof. Yi Yuan (IHEP, Beijing, China)

09:20 → 10:00 HEP and Beyond HEP Applications Techniques

Auditorium 111 (UERJ/Maracanã)

This session is dedicated to the applications of RPC technology in and beyond HEP (e.g., muography/tomography, medical imaging, security, neutron detection, cosmic-ray telescopes), including readout and system techniques enabling these use cases.

Convener: Eduardo Alves Coelho (Centro Brasileiro de Pesquisas Fisicas (CBPF))

09:20 RPC chambers in the COMET experiment Cosmic Ray Veto

The COMET experiment at J-PARC searches for the charged-lepton-flavour-
violating process of coherent muon-to-electron conversion in a muonic atom,
μ−N → e−N , with a target single-event sensitivity of O(10−15) during Phase I,
which is expected to begin in 2028. Low-energy negative muons are produced
by collisions of a high-intensity proton beam with an upstream production tar-
get and are transported downstream to the muon stopping target. The primary
Phase I signal is a track reconstructed in the Cylindrical Drift Chamber (CDC),
produced by an electron with an energy close to the muon rest mass.
The dominant background capable of mimicking this signal originates from
cosmic-ray muons. To identify and reject these events, COMET employs a Cos-
mic Ray Veto (CRV) system based, in part, on Resistive Plate Chambers (RPCs).
For the purpose of CRV design, the detector geometry can be approximated
as a rectangular enclosure. The most challenging region for the CRV is the
front side, which is directly exposed to intense neutron and electromagnetic
backgrounds originating from the upstream target. Simulations predict back-
ground hit rates of up to 2, kHz/cm2, significantly complicating the identifi-
cation of cosmic-ray muons. To address this challenge, we propose equipping
this region with improved RPC (iRPC) chambers developed for the Phase II up-
grade of the CMS experiment at CERN. During recent beam tests at the Gamma
Irradiation Facility (GIF++) at CERN, the iRPC chambers demonstrated stable
operation at background rates exceeding 3, kHz/cm2, providing a safety mar-
gin of 1.5 with respect to the maximum rates expected in COMET. An efficiency
of 95% was measured at the nominal expected background rate.
The left and right sides of the COMET detector are exposed to significantly
lower background levels, not expected to exceed O(100, Hz/cm2). For these
regions, IHEP (Beijing, China) has proposed the use of RPC detectors devel-
oped for the ARGO-YBJ experiment, which are similar in design to the ATLAS
Phase-0 RPC chambers. Although originally designed for cosmic-ray studies,
these detectors required adaptation to satisfy the COMET operating condi-
tions. Recent tests at GIF++ demonstrated stable operation up to 150, Hz/cm2
while maintaining an efficiency well above 95%.

Speaker: Dr Maxime Gouzevitch (Centre National de la Recherche Scientifique (FR))

09:40 Detector Physics-Driven Design of Future RPC and Hybrid Detectors

The RPC R&D effort of the last decades is culminating in the HL-LHC upgrades of the ATLAS and CMS systems and in the installation of pilot detectors for large Long-Lived Particle (LLP) experiments. In parallel, the need to drastically reduce the use of fluorinated gases has driven RPC research toward previously unexplored operating conditions, leading to promising results combining improved detector performance with reduced Global Warming Potential (GWP).
At the same time, the rapid progress toward future CERN colliders is stimulating a reassessment of the detector requirements. Although the expected particle rates at FCC-ee are relatively moderate, stringent demands are placed on timing performance, 3D tracking, bunch-crossing identification, fake-muon rejection, particle-flow calorimetry and searches for Beyond Standard Model (BSM) physics.
These developments provide the opportunity to revisit the detector physics governing RPC performance. The present study is based on a quantitative analysis of the primary-cluster statistics together with the concept of effective useful gas gap, showing that the detector efficiency is governed not only by the primary-ionization statistics but also by the interplay between gas mixture, avalanche development and front-end electronics. This framework demonstrates that modern ultra-low-noise electronics can substantially recover the efficiency loss expected from high-CO₂ low-GWP gas mixtures, providing a quantitative basis for the optimization of RPCs for future collider experiments.
Finally, to address the more demanding timing and rate requirements of FCC-ee time-of-flight applications, calorimetry and FCC-hh, a comparative study between MPGD-based and RPC-based hybrid photosensitive detectors will be presented. The discussion will show how RPC-based hybrid photosensitive detectors may offer intrinsic advantages when addressing the scalability challenge, which is expected to become the key discriminator among competing detector technologies for future collider experiments.

Speaker: Giulio Aielli (INFN e Universita Roma Tor Vergata (IT))

10:00 → 10:30 Coffee Break

11th-floor lobby, Block F, near Auditorium 111

10:30 → 11:30 HEP and Beyond HEP Applications Techniques

Auditorium 111 (UERJ/Maracanã)

This session is dedicated to the applications of RPC technology in and beyond HEP (e.g., muography/tomography, medical imaging, security, neutron detection, cosmic-ray telescopes), including readout and system techniques enabling these use cases.

Convener: Eduardo Alves Coelho (Centro Brasileiro de Pesquisas Fisicas (CBPF))

10:30 Cosmic-Ray Study of HSCP Search Capability Based on the CMS iRPC Prototype Readout System

Various Beyond-the-Standard-Model theories predict the existence of Heavy Stable Charged Particles (HSCPs), making their search one of the key objectives of the CMS Phase-II upgrade for the High-Luminosity LHC (HL-LHC). Owing to their large masses, HSCP candidates are expected to traverse the detector at velocities significantly lower than those of relativistic muons. Therefore, their flight velocity is a crucial feature distinguishing them from ordinary muons and an important observable for detector-based searches. As a fast-timing and large-area subdetector in the CMS muon system, the upgraded RPC electronics chain is expected to provide precise timing information for time-of-flight (TOF) measurements. This report first estimates the achievable timing performance of the RPC and iRPC system by combining the detector intrinsic time resolution with the TDC quantization uncertainty, and evaluates its impact on particle velocity resolution. The requirements on the data acquisition system raw-data readout window and the trigger coincidence window are then investigated to ensure that delayed HSCP signals across four RPC layers can be fully recorded and matched within the same trigger. To validate the TOF measurement chain, a four-layer cosmic-ray test platform based on the iRPC prototype was constructed at CERN 904, with an enlarged vertical spacing between the third and fourth layers to increase the flight path. After event selection and track-based reconstruction, the reconstructed cosmic-ray velocity distribution is found to be consistent with the expectation for near-light-speed muons. These results indicate that the upgraded CMS RPC electronics can provide sufficient TOF precision and effective local trigger support for HSCP searches.

Speaker: Zhen-An Liu (IHEP,Chinese Academy of Sciences (CN))

10:50 Performance Evaluation of a TOF-Tracker MRPC for Volcano Muography

We are developing an MRPC for imaging the internal structure of volcanoes and estimating soil water content using cosmic-ray muons.
Continuous observations of cosmic-ray muons may contribute to monitoring geophysical mass variations such as volcanic activity and soil moisture changes.
To identify high-energy penetrating muons, time-of-flight information from two MRPC layers is used to suppress background events.
For imaging the internal structure of volcanoes, this MRPC is required to achieve a time resolution better than 70 ps and a position resolution better than 0.2 mm.
A prototype TOF-tracker MRPC has been produced to provide high-precision timing and two-dimensional position measurements.
The detector employs 5-mm-pitch readout strips in two lengths, 500 and 1000 mm.
We have performed a beam test at the SPring-8/LEPS2 beamline and have been conducting a cosmic-ray test.
From these tests, we have evaluated how the time and position resolutions depend on the signal propagation distance along the readout strip and the electrode sheet resistance.
In this presentation, we will report the measured time and position resolutions and discuss the remaining challenges toward achieving the required performance for volcano imaging and soil water content estimation.

Speaker: Shintaro TANAKA (RCNP, The University of Osaka)

11:10 Gamma ray burst detection over a wide energy range with a ground-based detector

The experiment Argo-(Tibet 4300 m asl) has demonstrated the great RPC potential for gamma ray astrophysics with ground-based detectors. The Argo most relevant point was its very low energy threshold, approaching 100 GeV, which allowed to detect soft Extensive Air Showers (EAS) down to unprecedented energies. This feature offers a unique opportunity for the detection of Gamma Ray Bursts (GRB) at ground. Indeed, the gravitational collapse of a large mass emits, after a first 1 MeV burst, gamma rays of increasing energy. This late emission, lasting up a few days, can reach energies approaching 1 PeV. The challenge proposed in this talk is to follow the time evolution of a GRB starting from the minimum energy detectable at ground up to the burst extinction. A large area gamma ray observatory, combining RPCs and water-Cherenkov detectors, located in the Andes, would offer a unique possibility of exploring the southern hemisphere and center of our galaxy. This talk will present a new RPC generation optimized for mapping the secondary particles of an EAS reaching the ground. the simulation. Moreover, the simulation work course for lowering the EAS energy threshold down to a few tens of GeV and for selecting methods of gamma-hadron discrimination

Speaker: Rinaldo Santonico (INFN e Universita Roma Tor Vergata (IT))

11:30 → 13:50 Lunch

13:50 → 15:50 Applied research and new ideas

Auditorium 111 (UERJ/Maracanã)

This session is dedicated to exploratory R&D and new concepts: novel detector structures/materials, front-end electronics/DAQ, timing innovations, advanced algorithms (including ML), and unconventional applications or approaches.

Convener: Helena Brandao Malbouisson (Universidade do Estado do Rio de Janeiro (BR))

13:50 AN INTEGRATED PLATFORM FOR FABRICATION, CHARACTERIZATION AND AGING STUDIES OF MICROPATTERN GASEOUS DETECTORS

Future high-energy physics experiments demand micropattern gaseous detectors (MPGDs) with enhanced radiation tolerance, long-term stability and reliable operation under increasingly harsh conditions. Meeting these challenges requires a comprehensive understanding of the interplay between detector fabrication, materials properties, gas chemistry and aging mechanisms. To address this need, the University of São Paulo has established an integrated research platform dedicated to the complete experimental investigation of MPGDs throughout their lifecycle.
The platform combines complementary capabilities for detector development, advanced materials characterization and controlled aging studies. Alternative manufacturing approaches, including laser micromachining, lithographic processing and additive manufacturing, are being explored to enable novel detector geometries and local fabrication strategies. Structural and chemical characterization is performed using scanning electron microscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS) and near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS), providing detailed information on microstructure, elemental composition and surface chemistry. A dedicated aging facility equipped with real-time quadrupole mass spectrometry enables controlled irradiation experiments while continuously monitoring the evolution of the detector gas composition. These measurements are complemented by electrical characterization and numerical simulations to establish quantitative correlations between fabrication parameters, gas-phase reactions, surface modifications and detector performance.
The integration of these experimental capabilities within a single research infrastructure enables systematic studies that are difficult to achieve using isolated techniques. Rather than focusing on individual aspects of detector development, the platform provides a unified framework to investigate how fabrication processes influence detector operation and long-term degradation. This contribution presents the current status of the facility, its experimental capabilities and recent results demonstrating its potential as a comprehensive research environment for the development and understanding of next-generation micropattern gaseous detectors.

Speaker: Tiago Fiorini Da Silva (Universidade de Sao Paulo (BR))

14:10 Overview of Laser-Driven Multi-GeV Muon Sources and the ELI Beamlines plan

Recent improvements in laser technology have allowed on one hand to reach unprecedented levels of energy and intensity and on the other hand to develop new target systems to produce ever more energetic electron beams. These developments have made it possible to accelerate electrons up to 10
GeV in the space of 30 cm. The electron beam, interacting with a high-Z target can produce muons either via pair production with the Bethe-Heitler mechanism, or via the decay of mesons generated in photo- and electron-nuclear interactions. The production of muons using lasers has
been recently investigated and demonstrated by several teams worldwide.
This contribution will review the current status of laser-driven muon beams and the most notable experimental results. As well, it will detail the future plans for the development of a muon beam at the ELI Beamlines facility.

Speaker: Gabriele Maria Grittani

14:30 Development and Performance Evaluation of a Compact Portable Glass-RPC Muon Telescope for Muography Applications

Muon imaging (muography) exploits the natural flux of cosmic-ray muons to probe the internal structure of large or dense objects and has found an increasing amount of applications in areas including geoscience, nuclear safety, homeland security, civil engineering, mining industry and more. To enable muography measurements in logistically challenging environments, we are developing a compact, portable muon tracking system based on gas-tight glass Resistive Plate Chambers (gRPCs). The detector design prioritizes mechanical robustness, operational autonomy, safety, low gas flow or sealed mode operation, and cost-effectiveness, making it suitable for flexible field deployment. The envisaged modular telescope consists of multiple position-sensitive gRPC detector planes with active areas thus far ranging from 16x16 to 30x30 cm², and orthogonal strip readout planes providing 2D hit reconstruction and particle tracking, and should allow flexible telescope configurations tailored to different measurement scenarios.

The performance of the basic detector units has been characterized using cosmic-ray muons, demonstrating stable long-term operation, high detection efficiency, reliable timing performance, and sealed-mode gas stability. These studies provide first good indications of the suitability of the system for muographic applications requiring prolonged autonomous operation under demanding environmental conditions.

In 2025-2026, as part of an ongoing campaign to measure artificially generated muons, the gRPC detectors were deployed at the ELBA laser wake field multi-GeV electron accelerator at ELI Beamlines, where ultra-short, high-power plasma-laser interactions generate a complex and highly transient radiation environment. Initial results from these data-taking periods in very challenging conditions will be briefly presented.

Speaker: Michael Tytgat (Vrije Universiteit Brussel (BE))

14:50 Study of Rate Effects in a Photo-RPC with Different Bulk-Resistivity Electrodes Based on Stochastic Local Voltage-Drop Modeling

This work investigates rate effects in a photoelectric resistive plate chamber (Photo-RPC) operated in single-photoelectron mode, focusing on the role of electrode bulk resistivity and the underlying mechanism of timing degradation. The detector has a 215 μm gas gap filled with R134a/SF6/i-C4H10 (90/5/5), and a 355 nm femtosecond pulsed laser is used to control the incident photoelectron rate. Glass electrodes with different bulk resistivities are tested to compare gain stability and timing performance. The results show that lower-resistivity electrodes suppress gain reduction and extend the available rate range. A key observation is that, even at the same average gain, the time resolution under high-rate operation is worse than that obtained at low rate by reducing the applied voltage, indicating an additional degradation mechanism beyond the decrease in the average effective field. To explain this effect, a stochastic local voltage-drop model is developed based on local avalanche-charge accumulation and charge relaxation in the resistive electrode. The model shows that random intervals between successive events cause event-by-event fluctuations in local effective field, Townsend coefficient, and electron drift velocity, introducing extra timing jitter. Experimental-data resampling and Garfield++ simulations reproduce the measured gain loss and timing degradation, validating the proposed model.

Speaker: Mr Yiding Zhao (USTC(University of Science and Technology of China))

15:10 The TANGO_RD Project for the development and characterization of Resistive Cylindrical Chambers (RCCs): plans and preliminary results.

The TANGO_RD project aims to extensively characterize the physical behavior of Resistive Cylindrical Chambers (RCC), a new promising gas detector technology. This talk presents the three-year R&D program designed to deeply understand and optimize the RCC operational principles and to manufacture and test the first prototypes. We will first introduce the core characteristics, design advantages of the RCC architecture. Following this, the presentation will showcase the initial prototypes successfully constructed by the collaboration. We will report on their preliminary performance, highlighting the early results obtained from recent cosmic ray test campaigns. In parallel with hardware development, a dedicated software framework is being developed to accurately simulate the complex internal physics of the detector, including avalanche evolution and space charge dynamics. We will discuss these ongoing simulation activities and present the first preliminary comparisons between experimental data and Monte Carlo (MC) predictions that will guide the experimental research program of the TANGO_RD project.

Speaker: Davide Piccolo (INFN e Laboratori Nazionali di Frascati (IT))

15:50 → 16:20 Coffee Break

11th-floor lobby, Block F, near Auditorium 111

16:20 → 18:00 IAC and IOC Session

3017 A Meeting Room, Physics Institute

Conveners: Gilvan Augusto Alves (CBPF - Brazilian Center for Physics Research (BR)), Sandro Fonseca (Universidade do Estado do Rio de Janeiro (BR))

16:20 → 18:00 Outreach Event: GalileoMobile Amanar

Convener: Diego Torres Machado (Universidade do Estado do Rio de Janeiro)

16:20 GalileoMobile Amanar - Documentary

Abstract:

GalileoMobile Amanar is a science outreach and cultural heritage project that uses astronomy as a tool for inspiration, education, and the empowerment of the Sahrawi community. For decades, living under extremely challenging conditions in refugee camps near Tindouf, Algeria, Sahrawis have faced limited access to education, resources, and opportunities for young people.

In this context, the project brings children, teachers, and researchers closer to scientific knowledge about the Universe, while also valuing traditional Sahrawi knowledge of the sky. The initiative supports the establishment of a local structure dedicated to astronomy, provides training for teachers and researchers, and develops educational activities in schools and communities.

One of Amanar’s main goals is to preserve and pass on a threatened cultural heritage: ancestral knowledge about the stars and the sky, and their connection to Sahrawi life and culture. By placing Sahrawi researchers at the heart of this process, the project helps ensure that this knowledge is documented, shared with the community itself, and passed on to future generations. A documentary with English subtitles about the project will be shown with discussions at the end of the screening.

Trailer:

https://www.youtube.com/watch?v=QinQH92cN4k&t=14s

Resumo:

O GalileoMobile Amanar é um projeto de divulgação científica e valorização cultural que utiliza a astronomia como instrumento de inspiração, educação e fortalecimento da comunidade saaraui. Há décadas vivendo em condições extremamente adversas nos campos de refugiados próximos a Tindouf, na Argélia, os saarauis enfrentam limitações de acesso à educação, recursos e oportunidades para os jovens.

Nesse contexto, o projeto aproxima crianças, professores e pesquisadores do conhecimento científico sobre o Universo, ao mesmo tempo em que valoriza os saberes tradicionais saarauis sobre o céu. A iniciativa apoia a criação de uma estrutura local dedicada à astronomia, promove a formação de professores e pesquisadores e desenvolve atividades educativas em escolas e comunidades.

Um dos principais objetivos do projeto é preservar e transmitir um patrimônio cultural ameaçado: os conhecimentos ancestrais sobre as estrelas, o céu e sua relação com a vida e a cultura saaraui. Ao colocar pesquisadores saarauis no centro desse processo, o projeto contribui para que essa memória seja registrada, compartilhada com a própria comunidade e transmitida às novas gerações.Será exibido um documentário com legendas em inglês a respeito do projeto com discussões ao final da exibição.

Speakers: Diego Torres Machado (Universidade do Estado do Rio de Janeiro), Mauricio Thiel (Universidade do Estado do Rio de Janeiro (BR))

Friday 18 September

08:00 → 08:50 Registration

Entry to auditorium 111 (UERJ/Maracanã)

08:50 → 09:20 Plenary session

Auditorium 111 (UERJ/Maracanã)

Convener: Joao Pinheiro (Universidade do Estado do Rio de Janeiro (BR))

08:50 Ground-based gamma-ray astronomy: current status and expectations in the context of astroparticle physics.

Ground-based gamma-ray astronomy has consolidated itself as the fundamental branch of astroparticle physics dedicated to the study of cosmic-ray accelerators in the Universe, providing a precise diagnostic of the high-energy processes at work in the most extreme astrophysical environments. Ground-based gamma-ray detectors have achieved a high degree of experimental sophistication, combining both atmospheric and water-Cherenkov observations, as well as direct particle detection technologies to measure the products of air showers with high precision over a wide energy range, from tens of GeV to beyond the PeV. Thanks to these technical achievements, the most recent observatory proposals that have come online in the past few years, or that are being planned this decade, provide a unique context of discovery and expansion that will mark the climax of the long history of the field. In this contribution I plan to give an overview of where the field stands within the broader context of astroparticle physics and the expected achievements towards the end of the decade.

Speakers: Ulisses Barres (Centro Brasileiro de Pesquisas Físicas), Ulisses Barres de Almeida (Brazilian Center for Physics Research (CBPF))

09:20 → 10:00 Applied research and new ideas

Auditorium 111 (UERJ/Maracanã)

This session is dedicated to exploratory R&D and new concepts: novel detector structures/materials, front-end electronics/DAQ, timing innovations, advanced algorithms (including ML), and unconventional applications or approaches.

Convener: Joao Pinheiro (Universidade do Estado do Rio de Janeiro (BR))

09:20 Development of MRPCs for J-PARC and muography

We are developing TOF and TOF-tracker MRPCs for the J-PARC MARQ experiment and muography applications.
The TOF MRPC will be used as a particle-identification (PID) detector in the MARQ spectrometer at the high-momentum beamline of J-PARC.
In contrast, the TOF-tracker MRPC is being developed as a muon detector providing both position and timing information.
These MRPCs share a common detector structure and front-end electronics.
We have developed new construction techniques, such as a novel high-voltage electrode that can be printed on PET films, gas spacers made from double-sided adhesive tape.
We are also developing a gas-tight sealing system in which only glass plates are sealed.
In addition, we are developing low-noise front-end electronics compatible with triggerless streaming DAQ systems.
In this contribution, we describe the key technologies developed for these MRPC detectors.

Speaker: Natsuki Tomida

09:40 A "warm" MRPC for the high-rate charged-particle identification in proton-nucleus collisions at J-PARC

J-PARC E88/SA$\Phi$RE experiment aims at elucidating the chiral-symmetry restoration of the $\phi$ meson inside the nuclei by measuring its $K^{+}K^{-}$ decay in proton-nucleus collisions at 30 GeV/c. We have developed an MRPC with high-rate capability by warming the glass stack, aiming at precise time-of-flight measurements for $K^{\pm}$ identification. In E88/SA$\Phi$RE, we measure $\phi \rightarrow K^{+}K^{-}$ in proton-nucleus collisions at 1 MHz. The expected hit rate in the MRPC is 1 KHz/cm$^{2}$ at maximum. The MRPC consists of double glass stacks, each of which consists of 5 gaps with 6 glass sheets with a sensitive area of 230 mm $\times$ 750 mm. We achieved a timing resolution of $70-100$ ps in cosmic-ray and beam tests, and improved the timing resolution by a few % by raising the temperature from $\sim25^\circ$C to $\sim40^\circ$C. We also discuss the temperature dependence of the streamer contribution through waveform analysis of the signal. In this presentation, we will show the design of the MRPC for J-PARC E88, its performance in cosmic-ray and beam tests, and a plan for the J-PARC E88 experiment.

Speaker: Dr Hiroyuki Sako (Japan Atomic Energy Agency)

10:00 → 10:30 Coffee Break

11th-floor lobby, Block F, near Auditorium 111

10:30 → 11:50 Applied research and new ideas

Auditorium 111 (UERJ/Maracanã)

This session is dedicated to exploratory R&D and new concepts: novel detector structures/materials, front-end electronics/DAQ, timing innovations, advanced algorithms (including ML), and unconventional applications or approaches.

Convener: Marcia Begalli (Universidade do Estado do Rio de Janeiro (BR))

10:30 Machine Learning-Based Suppression of Secondary Hit Background in Low-Resistive RPCs

Resistive Plate Chambers (RPCs) are widely used as tracking detectors in high-energy physics experiments due to their simplicity, robustness, and excellent timing performance. However, low-resistive bakelite RPC prototypes often exhibit secondary hit components that degrade time and position resolution and introduce background, complicating track reconstruction. In this work, we present a data-driven approach to identify and suppress such background clusters using supervised machine-learning techniques. A set of fifteen compact, physically motivated cluster-level observables–capturing statistical and shape-related properties of time and ADC distributions–is constructed from controlled laboratory measurements with a single-gap RPC operated under a three-scintillator coincidence trigger. Three classification models–Deep Neural Network (DNN), one-dimensional Convolutional Neural Network (1D-CNN), and XGBoost–are trained and evaluated under identical conditions. All models achieve efficient signal–background separation, with XGBoost providing the most stable performance. Feature-importance analysis indicates that cluster size and temporal-shape parameters are the most discriminating observables. The proposed method is computationally efficient and relies only on compact cluster descriptors, making it well suited for integration into real-time or near real-time reconstruction pipelines in high-rate experiments.

Speaker: Souvik Chattopadhay (Department of Atomic Energy (IN))

10:50 Development of a Cosmic Muon Trigger System for CERN-GIF++

GIF++ (Gamma Irradiation Facility) is a CERN multiuser facility dedicated to the characterization and qualification of particle detectors under radiation conditions as expected at the LHC (Large Hadron Collider) and the future HL-LHC. It combines a high-activity 137Cs gamma source, adjustable attenuation filters, and a high-energy muon beam, providing a unique environment for detector studies.
A cosmic muon trigger system is being developed for GIF++ and will become particularly important during LS3 (Long Shutdown 3), when the CERN accelerator complex will be unavailable for beam operation due to the upgrades required for the HL-LHC. The project includes all the development, detector simulation, acceptance studies, mechanical design, electronics integration, system assembly, commissioning, and performance evaluation.
This contribution presents an overview of the ongoing project and its current development status. The facility requirements, detector acceptance studies, simulation framework, data acquisition concepts, mechanical integration, and the different trigger system configurations under consideration will be discussed. Particular emphasis will be given to the design choices being evaluated and to the studies performed to assess their feasibility and performance for future operation at GIF++ during LS3.
Different detector technologies are being considered as candidates for the trigger system. The first simulation studies and commissioning activities presented in this work focus on spare CMS barrel RPCs, which constitute one of the available options due to their proven reliability and availability. These chambers continue to operate successfully after nearly two decades of service. Simulation results and initial characterization studies obtained with barrel RPCs will be presented, together with an overview of alternative detector solutions currently under evaluation. The results demonstrate the feasibility of constructing a robust and large-area cosmic trigger system capable of supporting detector R&D, quality control, and performance studies throughout the LS3 period.

Speaker: Katherine Maslova (UERJ/CERN)

11:10 Strategies to reduce greenhouse gas emissions from particle detector operation at CERN

Several gaseous detector installations at CERN make use of gas mixtures containing greenhouse gases, such as R-134a, SF6 and CF4. Due to the decreasing availability of these gases in the European Union and their consequent cost increase, several strategies have been implemented to reduce their use as much as possible.
Gas systems are responsible for preparing the gas mixture, recirculating it where possible, providing the required flows and pressures, purifying the mixture, and analysing it to ensure an optimal composition.
One main strategy to reduce greenhouse gas emissions consists of optimising the medium and large gas systems that provide the gas mixture to large detector installations at CERN experiments and facilities. In particular, employing gas recirculation and tuning the operational parameters to the needs of the detector can account for up to 90% of the initial GHG reduction.
A second approach consists of recovering the gas that cannot be recirculated. Techniques based on fractional and azeotropic separation, as well as membrane adsorption, are being used to operate several GHG recovery plants. New materials from the family of Metal-Organic Frameworks are also being studied and evaluated as possible candidates for new and efficient gas adsorption processes.
A third research line consists of identifying alternative gas mixtures, applying them to existing installations, and paving the way to ensure that future detector systems can be operated with more eco-friendly alternatives.
An overview of the current research lines and strategies to reduce greenhouse gas emissions from particle detector operation at CERN will be presented in this contribution.

Speaker: Gianluca Rigoletti (CERN)

11:30 On a new RPC signal readout

Usual RPC readout is made with long strips a few centimeters wide which behave like signal transmission lines of quite good quality that inject the signal in the front-end electronics circuit located at the strips ends. We present here an alternative readout made with 40x40 cm2 square pads which strongly reduce the number of channels required to cover large sensitive areas.
The signal pickup point, which is located at the center of the pad, reduces the signal path length to the front-end electronics and strongly improves the external noise shielding. We show here that, despite large pad capacitance, charge signals as low as 300 fC can easily be detected by front-end electronics and the typical time resolution of a 2mm gas gap RPC is preserved. We present here a full test of a chamber 80x280 cm2 equipped with 16 readout pads and powered by a DC-DC high voltage supply integrated on the chamber Faraday cage. The test results show time resolution, detection efficiency, cluster size, external noise and spontaneous sparking as a function of high voltage and front-end electronic threshold.

Speaker: Rinaldo Santonico (INFN e Universita Roma Tor Vergata (IT))

11:50 → 13:50 Lunch

13:50 → 14:50 Summary Talk

Auditorium 111 (UERJ/Maracanã)

Conveners: Gilvan Augusto Alves (CBPF - Brazilian Center for Physics Research (BR)), Sandro Fonseca (Universidade do Estado do Rio de Janeiro (BR))

14:50 → 15:10 Poster prize

Auditorium 111 (UERJ/Maracanã)

Conveners: Kevin Mota Amarilo (Universidade do Estado do Rio de Janeiro (BR)), Mapse Barroso Ferreira Filho (Universidade do Estado do Rio de Janeiro (BR))

15:10 → 15:50 Closure ceremony: next RPC Conference

Auditorium 111 (UERJ/Maracanã)

Conveners: Gilvan Augusto Alves (CBPF - Brazilian Center for Physics Research (BR)), Sandro Fonseca (Universidade do Estado do Rio de Janeiro (BR))

15:50 → 16:20 Coffee Break

11th-floor lobby, Block F, near Auditorium 111