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Physics Physics Instrumentation and Detectors

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Monday 28 September

Instrumentation and Detectors

A linear Paul trap to study the equilibrium of charged micron-sized particles in air

Roxen Wilby Kissangou, Marius Romuald Kamsap, Mike Delon Mboumba et al. (+2 more)

We describe and use a macroscopic linear quadrupolar trap to explore the trapping and equilibrium properties of charged particles. These devices, when operated to trap atomic ions, are at the core of ion based quantum computer and optical atomic clock. To illustrate the characteristics of few particle trapping, and observe different force balance on a charged particle, a macroscopic linear trap, operating at room condition, is trapping micrometer-sized particles. Compared to atomic or molecular ions, their mass can not be neglected and requires an extra voltage for gravity force compensation. We show how this compensation can be demonstrated experimentally and that the choice of hollow-core glass spheres has the advantage of a good reproducibility of the experiments, that allows one to deduce with good precision the charge-to-mass ratio of the trapped particle.
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All authors Roxen Wilby Kissangou, Marius Romuald Kamsap, Mike Delon Mboumba, Marie Houssin, Caroline Champenois

Instrumentation and Detectors

EXO-200 Public Data Release for AI/ML Applications

S. Al Kharusi, G. Anton, I. Badhrees et al. (+103 more)

We present a public release of a subset of calibration data from the EXO-200 experiment, a liquid xenon time projection chamber designed to search for neutrinoless double-beta decay in $^{136}$Xe. The released dataset consists of approximately one million events collected during $^{228}$Th calibration campaigns performed near the end of Phase-II operations between February 26 and March 2, 2018. For each event, the dataset includes raw detector waveforms from the U-wire, V-wire, and avalanche photodiode (APD) readout channels together with reconstructed event quantities including charge energy, light energy, rotated energy, and charge-cluster information. The dataset is distributed in HDF5 format and is intended to support data preservation, educational activities, and the development of modern machine-learning techniques for rare-event physics. This paper describes the detector, dataset contents, file structure, and public access mechanism.
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All authors S. Al Kharusi, G. Anton, I. Badhrees, P. S. Barbeau, V. Belov, T. Bhatta, M. Breidenbach, T. Brunner, G. F. Cao, W. R. Cen, C. Chambers, B. Cleveland, M. Coon, A. Craycraft, T. Daniels, L. Darroch, S. J. Daugherty, J. Davis, S. Delaquis, A. Der Mesrobian-Kabakian, R. DeVoe, A. Dolgolenko, M. J. Dolinski, J. Echevers, B. Eckert, W. Fairbank Jr., D. Fairbank, J. Farine, S. Feyzbakhsh, P. Fierlinger, Y. S. Fu, D. Fudenberg, P. Gautam, R. Gornea, G. Gratta, C. Hall, E. V. Hansen, J. Hoessl, P. Hufschmidt, M. Hughes, A. Iverson, A. Jamil, C. Jessiman, M. J. Jewell, A. Johnson, A. Karelin, L. J. Kaufman, T. Koffas, R. Krücken, A. Kuchenkov, K. S. Kumar, Y. Lan, A. Larson, B. G. Lenardo, D. S. Leonard, G. S. Li, S. Li, Z. Li, C. Licciardi, Y. H. Lin, R. MacLellan, T. McElroy, T. Michel, B. Mong, D. C. Moore, K. Murray, O. Njoya, O. Nusair, A. Odian, I. Ostrovskiy, H. Peltz Smalley, A. Perna, A. Piepke, A. Pocar, F. Retière, A. L. Robinson, P. C. Rowson, S. Schmidt, D. Sinclair, K. Skarpaas, A. K. Soma, V. Stekhanov, M. Tarka, S. Thibado, J. Todd, T. Tolba, T. I. Totev, R. Tsang, B. Veenstra, V. Veeraraghavan, P. Vogel, J.-L. Vuilleumier, M. Wagenpfeil, J. Watkins, M. Weber, L. J. Wen, U. Wichoski, G. Wrede, S. X. Wu, Q. Xia, H. Xu, D. R. Yahne, L. Yang, Y.-R. Yen, O. Ya. Zeldovich, T. Ziegler

Saturday 26 September

Instrumentation and Detectors

Modeling the Effects of Temperature and Electric Field on the Dark Count Rate of Photomultiplier Tubes

Yuto Maekawa, Masamitsu Fukazawa and Yasuhiro Nishimura

Although photomultiplier tubes (PMTs) are sufficiently sensitive for applications based on counting single photons, the thermionic emission of electrons from the photocathode is one of the dominant background sources. In this study, we modeled the dark count rate of a given PMT as a function of the temperature and external electric field based on the Richardson-Dushman equation and incorporated the Schottky effect. To validate the model, measurements were performed using an eight-centimeter Hamamatsu R14374 PMT equipped with a bialkali photocathode. The dark count rate was measured over a range of temperatures from 10 to 40 degree Celsius. An external electric field was applied to the outside surface of the optical window with the photocathode by varying the potential difference between the photocathode and the surrounding medium from 0 to 1100 V. The result confirmed that the influence of the external potential difference remained relatively small within a difference of 200 V, with the increase in the dark count rate remaining below 50 % across all measured temperatures. This behavior was incorporated into the proposed model by including an error function to predict the dark count rate under operating conditions with varying temperatures and external electric fields.
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Instrumentation and Detectors

Enhancing Conversion Gain in HEB Mixers using Negative Differential Resistance

Boris S. Karasik and Changyun Yoo

This work investigates how negative differential resistance (NDR) can be utilized to enhance conversion gain in superconducting niobium nitride (NbN) hot-electron bolometer (HEB) mixers. Conventional HEB operation avoids NDR regions due to parasitic oscillations caused by interactions between thermal inertia and bias-line reactance. Recent experimental results show that reducing the bias-T inductance suppresses these oscillations and enables stable biasing within the NDR regime, thereby increasing the mixer conversion gain beyond levels achievable under positive differential resistance (PDR) bias. Using a lumped thermal-electrical model, we interpret these experimental findings, derive stability conditions for NDR-biased operation, and predict the future performance limits achievable through optimized bias circuit designs. Our results indicate that further reductions in bias inductance, combined with appropriate load-line conditions, could yield several decibels of additional gain while maintaining practical IF bandwidths.
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Friday 25 September

Instrumentation and Detectors

Development of LGAD Sensor Technology on 12 inch Wafers for 3D Integration with advanced CMOS processes

Ron Lipton, Julie Segal, Angela Kok et al. (+10 more)

We report on the design, simulation, and initial testing of Low Gain Avalanche Diode (LGAD) sensors fabricated in 65 nm CMOS technology on 12 inch wafers. These sensors were developed as part of a project to demonstrate full wafer to wafer hybrid bonding of sensors and 28 nm Readout Integrated Circuits (ROICs). The sensor submission and test included standard (reach-through) LGADs, AC coupled LGADs, and Deep Junction LGADs as well as various test structures.
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All authors Ron Lipton, Julie Segal, Angela Kok, Troy England, Artur Apresyan, Davide Braga, Farah Fahim, Shuoxing Wu, Christopher Kenney, Bojan Markovic, Ariel Gustavo Schwartzman, Lorenzo Rota, Arthur Carpenter

Instrumentation and Detectors

WLCG Mini-Capability Challenge: Host Tuning to Im- prove WAN Data Transfers

Andrew Malone Melo, Carlos Fernando Gamboa, Diego Devila Foyo et al. (+8 more)

High-throughput data movement is a defining requirement of the WLCG computing model, yet end-to-end performance is often constrained less by the network backbone than by host-level configuration. We present the results of a WLCG mini-capability challenge focused on host optimization at ATLAS and CMS sites (FNAL, UCSD, UNL, BNL, AGLT2, MWT2, and Vanderbilt), using EL8/9 hosts with 25\,Gbps or higher NICs. NET2 participated in a subsequent trans-Atlantic test. The methodology combines ESnet Fasterdata guidance with the OSG-hosted fasterdata-tuning.sh framework, applying TCP, queue, offload, and ring-buffer tuning with save and restore support for safe baseline comparisons. Results show that tuning benefit depends critically on the local bottleneck. Where DTNs and storage were both capable (UNL), FTS throughput rose from 60 to 90\,Gbps. Where storage was the binding constraint (UCSD), iperf3 throughput improved from 20 to 90\,Gbps while FTS was unchanged. Where the NIC was the binding constraint (Vanderbilt, 25\,G NIC), the tuning profile actively reduced throughput, motivating a review of per-site applicability. The challenge also surfaced and resolved a dCache proxying misconfiguration at AGLT2, demonstrating that mini-challenges serve a diagnostic function beyond raw performance measurement.
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All authors Andrew Malone Melo, Carlos Fernando Gamboa, Diego Devila Foyo, Eduardo Bach, Eli Dart, Shawn McKee, Garhan Attebury, Philippe Laurens, Wendy Wu, Syed Asif Shaw, Hiro Ito

Instrumentation and Detectors

Quantitative characterization of superconducting qubits as particle detectors

Francesco De Dominicis, Raja Yasir Mehmood Khan, Dounia L Helis et al. (+22 more)

Ionizing radiation is a major source of correlated errors in superconducting quantum processors, yet the mechanisms responsible for the qubit response to particle interactions remain only partially understood. In this work, we operate superconducting qubits as particle detectors while simultaneously monitoring the deposited energy with an independent semiconductor cryogenic sensor. This complementary measurement provides an absolute determination of the particle interaction rate in the chip, enabling the first direct measurement of the detection efficiency of superconducting qubits exposed to environmental radiation. We measure individual qubit detection efficiencies of about 30-40$\%$, increasing to approximately 50$\%$ when combining the response of two qubits. Under the conservative assumption that the efficiency loss is entirely determined by a finite detection threshold, we derive an upper limit on the effective energy threshold of the detector of $70\pm20~\mathrm{(stat)}\pm30~\mathrm{(syst)}~\mathrm{keV}$. Measurements with radioactive sources producing different deposited-energy spectra further show that the detection efficiency decreases for lower-energy interactions. We further investigate the origin of the qubit response by injecting controlled thermal pulses with a resistive heater. Although these pulses deposit energies comparable to those released by particle interactions, they do not reproduce the radiation-induced signatures, demonstrating that the qubit response to radiation cannot be explained by a transient increase in substrate temperature alone. Our results establish an experimental framework for quantitatively connecting particle energy deposition to radiation-induced responses in superconducting quantum circuits.
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All authors Francesco De Dominicis, Raja Yasir Mehmood Khan, Dounia L Helis, Ambra Mariani, Letizia Tirabasso, Alberto Ressa, Mustafa Bal, Fabio Bellini, Camilla Bonomo, Nicola Casali, Gianluigi Catelani, Ivan Colantoni, Francesco Crisa, Angelo Cruciani, Sabrina Garattoni, Luca Gironi, Andrea Melchiorre, Lorenzo Pagnanini, Valerio Pettinacci, Stefano Pirro, Andrei Puiu, Tanay Roy, Shaojiang Zhu, Anna Grassellino, Laura Cardani

Instrumentation and Detectors

Transition Radiation Detector Upgrade for the GlueX-III Charmonium Program

Lauren Kasper, Alexander Austregesilo, Cody Dickover et al. (+9 more)

The GlueX-III experiment at Jefferson Lab, planned to run in 2027-2029, will enhance the laboratory's capability to explore charmonium production near threshold and related aspects of QCD in the non-perturbative regime. A central upgrade for GlueX-III is a large-scale triple-GEM Transition Radiation Detector (TRD) optimized for electron identification and pion suppression in the hadron-rich environment of fixed-target photoproduction. This document describes the motivation for and efforts related to such an upgrade, including the design, construction, and performance of a 720x528mm$^{2}$ triple-GEM-TRD prototype that was tested in the existing GlueX-II experimental acceptance during the 2025 run. Results validate the prototype's integration, timing performance, and electron identification capability. Its projected impact in the GlueX-III setting is discussed, with background reduction in a $J/\psi$ candidate sample demonstrated. The development and use of a modern TRD technology in a high-background environment at Jefferson Lab may inform detector design choices as a future upgrade path for the EIC.
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All authors Lauren Kasper, Alexander Austregesilo, Cody Dickover, Sean Dobbs, Sergey Furletov, Yulia Furletova, Ilya Larin, Lubomir Pentchev, Saheli Rakshit, Nizar Septian, Simon Taylor, Julia Velkovska

Instrumentation and Detectors

Time-Resolution Function of the RADEX Neutron Source

R. M. Djilkibaev

The time-resolution function is one of the key factors determining the accuracy of neutron-resonance parameter reconstruction in time-of-flight experiments. A method is proposed for determining the time-resolution function of the RADEX neutron source associated with neutron slowing down in the target, based on detailed Geant4 modeling. The neutron time spectra obtained in the Geant4 simulations are approximated by a sum of three Gamma functions with dimensionless parameters. This model is shown to describe the shape of the time distributions well over the neutron-energy range 50–300 eV. To test the applicability of the proposed approach to a source of a different design, a comparison is made with the calculated n\_TOF time-resolution function. Its shape is also shown to be well described by a three-component Gamma model.
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Instrumentation and Detectors · Cross-listed from hep-ex

Suitability studies of exotic muon decay at the High Intensity heavy-ion Accelerator Facility

Lingzhi Dong, Jinning Li, Leyun Gao et al. (+8 more)

We present a detailed feasibility study of exotic muon decay searches using the muon beam at the High Intensity heavy-ion Accelerator Facility (HIAF). For the decay channel mu to eX0, where X0 denotes a new boson featuring LFV couplings, the produced electron carries very low energy when the mass of X0 approaches the muon mass, making detection challenging. Nevertheless, the high-energy beam at HIAF can boost these electrons up to a measurable energy range. The detector system proposed here comprises front-end scintillators for particle identification (PID) and a main detector consisting of an RPC stack to track decay products and a scintillator for energy measurement. Leveraging the kinematic properties of low momenta and small emission angles of signal electrons, we employ optimized momentum and angular acceptance cuts on the RPC detector to efficiently suppress background events. With this strategy, we obtain an upper limit of 1e-5 on the branching ratio of the exotic muon decay at 95% confidence level, achieving state-of-the-art sensitivity.
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All authors Lingzhi Dong, Jinning Li, Leyun Gao, Cheng-en Liu, Yu Xu, Xuecheng Zhang, Liangwen Chen, Qite Li, Chen Zhou, Qiang Li, Zhiyu Sun

Instrumentation and Detectors

Parnassus for the CLD Detector: A Generative Machine-Learning Surrogate for Detector Simulation and Reconstruction at the FCC-ee

Umar Sohail Qureshi, Benjamin Nachman and Caterina Vernieri

Detector simulation and event reconstruction will be computationally expensive for future $e^+e^-$ collider programs and are currently critical bottlenecks for accurate feasibility studies. To address this challenge, we build a Parnassus model for the CLD detector concept. Parnassus is a framework for automatically tuning a surrogate model, in our case, a conditional flow matching neural network, to emulate a full detector simulation and reconstruction. We train on $e^+e^-\to Z\to q\bar q$ events at $\sqrt{s}=91.2$ GeV processed through a Geant4 simulation of the CLD detector concept and the Pandora particle-flow reconstruction and reproduce single-particle kinematics, particle-IDs, and impact-parameter distributions. We also examine jet- and event-level features, inclusively and split by flavor, and find excellent fidelity, significantly better than the parameterized program Delphes. Furthermore, we train a transformer-based flavor tagger on the reconstructed particle-flow constituents and show that the surrogate preserves the $b/c/s/q$ discrimination of the full CLD reconstruction. The Parnassus CLD model achieves a generation cost of about 1.2 ms (40 ms) per event on a single GPU (CPU), over three (two) orders of magnitude faster than full simulation and reconstruction. Our model is publicly available for feasibility and design studies.
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Thursday 24 September

Instrumentation and Detectors · Cross-listed from physics.ed-ph

CMS Open Data Visualization with FireworksWeb

Yuxiao Wang, Alja Mrak-Tadel, Matevž Tadel et al. (+4 more)

FireworksWeb is a web-based event display utilizing a C++ ROOT-Eve backend with SAPUI5 frontend for interactive 3D visualization of particle physics events directly in the browser. Building upon ROOT-Eve and RenderCore, it eliminates local software installation while maintaining professional-grade event display capabilities. FireworksWeb is currently deployed for live event monitoring in the CMS control room, demonstrating its reliability for real-time data visualization in production environments. The CMS experiment has made a large amount of collision datasets publicly available through the CERN Open Data portal, which are the valuable resources for education, outreach, and research. We have extended FireworksWeb to enable visualization of these open datasets, making particle physics data accessible to diverse audiences without requiring local software installation. Our prototype implementation includes standalone cameras, event filters, configurable collection settings, and projection controls with fish-eye distortion for cylindrical geometries. The web architecture communicating via CGI enables dataset queries and filtered event selection based on physics criteria. We demonstrate the prototype with CMS Open Data events, discuss the technical architecture, and outline applications for education, public outreach, and exploratory physics analysis.
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All authors Yuxiao Wang, Alja Mrak-Tadel, Matevž Tadel, Avi Yagil, Mario Masciovecchio, Dmytro Kovalskyi, Sergey Linev

Instrumentation and Detectors

Point-cloud generative models for fast calorimeter simulation across particles and geometries

Thorsten Buss, Henry Day-Hall, Frank Gaede et al. (+7 more)

Detailed Geant4 simulation of calorimeter showers is the largest single computing cost of collider experiments, and the High-Luminosity LHC will need about ten times more simulated events than are currently produced. We summarise recent progress in generative point cloud fast simulation for highly granular calorimeters. CaloClouds3 generates photon (electromagnetic) showers, is geometry-independent, and runs on average about 120x faster than Geant4 on a single CPU. CaloHadronic uses transformer attention to extend the point cloud diffusion approach to pion (hadronic) showers spanning the electromagnetic and hadronic calorimeters. AllShowers unifies twelve particle types in a single model with far fewer parameters than the specialised baselines while matching or exceeding their fidelity. We close with cross-geometry transfer learning, which needs two to three orders of magnitude fewer training showers while preserving the generative performance.
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All authors Thorsten Buss, Henry Day-Hall, Frank Gaede, Gregor Kasieczka, Katja Krüger, Anatolii Korol, Thomas Madlener, Peter McKeown, Martina Mozzanica, Lorenzo Valente

Instrumentation and Detectors · Cross-listed from physics.med-ph

Melanin- and linewidth-corrected pulse-oximetry

Giles Blaney, Jodee Frias, Ravi Durbha et al. (+2 more)

Current pulse oximeters tend to overestimate arterial saturation in darkly pigmented patients, increasing occult hypoxemia rates. One proposed mechanism is spectral coloring: melanin contributes to reshaping the detected spectrum of a broad-linewidth source, making the wavelength-dependent parameters behind calibration skin-tone-dependent. Diffuse optics theory allows for a melanin- and linewidth-corrected calibration equation, which to our knowledge has never been tested in vivo. In this work, we fit the empirical linear equation, the diffuse optics theoretical equation, and its corrected form to the public OpenOximetry Repository—considering 98 patients with paired arterial blood-draws, raw photoplethysmograms, and skin reflectance spectra. Accuracy is practically indistinguishable between the three approaches, yet the saturation error's dependence on melanin falls from +2.8 to +1.2 to +0.1 percentage points per unit melanin volume fraction—consistent with the spectral-coloring theory. None of these dependencies on melanin are statistically resolved here—a cohort roughly ten times larger is needed—so the correction is backed by theory and its expected direction. All three calibration approaches carry two degrees of freedom: the theoretical equation drops into existing calibration procedures, and its melanin-aware form needs a per-patient skin-tone measurement. This work demonstrates how the theoretical pulse oximetry model can be applied in calibration.
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All authors Giles Blaney, Jodee Frias, Ravi Durbha, Sergio Fantini, Valencia Koomson

Instrumentation and Detectors · Cross-listed from cond-mat.mtrl-sci

Ultrafast Electron Microscopy: A Quantitative Platform for Nonequilibrium Materials Research

David J. Flannigan and Swarit Ahmed Shadman

Macroscopic materials function is determined not merely by equilibrium structure, but by how carriers, phonons, fields, defects, interfaces, and collective order dynamically evolve after perturbation. Ultrafast electron microscopy (UEM) uniquely bridges this gap, coupling femtosecond-to-nanosecond timing with real-space, reciprocal-space, and energy-resolved contrast. Here, we review how these integrated capabilities now quantitatively map energy flow and conversion in electronic materials, decode electronic-structural coupling in quantum and correlated systems, and isolate the localized propagation of carriers, polaritons, strain, and phonons across optoelectronic and nanomechanical architectures. We emphasize the predictive design rules now emerging from direct metrology of carrier-lattice coupling, momentum-resolved phonon thermalization, defect-controlled phase transformations, and authentic operando switching. We critically assess UEM's ongoing maturation from a qualitative, proof-of-concept experiment into a rigorous, quantitative materials platform. This paradigm shift is actively driven by integrated multimodal detection, advanced energy-resolved spectroscopy, high-repetition-rate sources, multidimensional (4D and 5D) acquisition, and physically constrained forward modeling. Ultimately, the central opportunity lies in establishing a complete, causal link from initial excitation to localized energy flow, transient structure, and macroscopic device function. By prioritizing quantitative reproducibility and robust mechanistic interpretation, UEM is positioned to engineer materials in functional states that equilibrium thermodynamics simply cannot describe.
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Instrumentation and Detectors

Impact of the position effects in the energy calibration of the BULLKID detector

Matteo Folcarelli, Matteo Cappelli, Giorgio Del Castello et al. (+6 more)

BULLKID is a cryogenic solid-state detector based on an array of silicon dice equipped with Kinetic Inductance Detectors (KIDs) for low-mass dark matter searches and coherent elastic neutrino-nucleus scattering. Energy calibration can be performed using optical LED photon bursts, which are absorbed within the first few hundred nanometers of the substrate. An energy calibration using a $^{241}$Am gamma-ray source revealed a $<10\%$ discrepancy with the LED calibration. A recent study by Matava and Williams suggested that phonon statistics and phonon collection varying with the interaction position could explain such a discrepancy. This work evaluates the impact of these effects on the calibration of the BULLKID detector, demonstrating they both have a negligible effect. We clarify the results obtained during the $^{241}$Am calibration regarding the origin of the observed discrepancy.
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All authors Matteo Folcarelli, Matteo Cappelli, Giorgio Del Castello, Camilla Bonomo, Angelo Cruciani, Daniele Delicato, Leonardo Pesce, Davide Quaranta, Marco Vignati

Instrumentation and Detectors · Cross-listed from cs.RO

High-Voltage Optocoupler Amplifier for Electrostatic Actuators

George C. Jurgiel, Alex S. Miller and Jeffrey H. Lang

Many electrostatic actuators require multi-kilovolt drive voltages at sub-milliamp currents, a task poorly suited for conventional switching devices. As an alternative, we demonstrate a high-voltage amplifier using optocouplers as active elements. The amplifier produces a 20-kV peak-to-peak output with up to 500 Hz bandwidth while maintaining a minimal component count. By using optocouplers as linear devices in feedback, lower harmonic distortion and higher bandwidth are achieved than offered by equivalent PWM amplifiers. This design improves the viability of electrostatic actuators by providing a simpler method to achieve useful drive waveforms.
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Instrumentation and Detectors · Cross-listed from physics.optics

Fiber-based scanning levitated nanoparticle force sensor near a metalized membrane

Andrew M. Dana, Samuel J. Borden, Nia Burrell et al. (+10 more)

We describe a fiber-based dual-beam trap for dielectric nanospheres with the ability to transfer the trapped particles into a retro-reflective standing-wave trap within micron-range distances of a metallic mirror surface. We illustrate its capability for three dimensional scanning force sensing over a several square micron area of an ultra-thin gold-coated silicon nitride mirror-membrane with a total thickness of approximately 370~nm. We also demonstrate three-dimensional laser feedback cooling and zeptonewton force resolution in high-vacuum at micron range from the membrane, showing promise for future improved tests of gravity at short distances and other surface force investigations. By using charged nanospheres, we expect the method may be useful for studying fluctuating patch potentials and electric field noise in the vicinity of a surface in the $\sim$ kHz to $\sim 100$ kHz frequency regime.
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All authors Andrew M. Dana, Samuel J. Borden, Nia Burrell, Chethn Galla, Alexey Grinin, Mark Nguyen, Kristina Menon, Shafaq Elahi, Katarina Boskovic Guy, Andrew Laeuger, Evan Weisman, Gambhir Ranjit, Andrew A. Geraci

Instrumentation and Detectors · Cross-listed from physics.optics

Breakdown of Axis Separability and Structured Inversion in Finite-Domain Normalized Position Measurements: A Quadrant Photodetector Case Study

Zhiqian Su

Finite-domain normalized spatial measurements combine an incident field, geometric support, local response, and channel weighting. These operations can break an otherwise separable response, so accurate single-axis calibration alone does not establish separability of a multidimensional measurement. We represent normalized readouts as channel-weight expectations under a parameter-dependent effective measure. For fixed reception and channel operators, local sensitivity is the covariance between the channel weight and the source score. This representation distinguishes axis separability, parameter mixing, and local recoverability, and applies at the appropriate detector level to continuous-electrode position-sensitive detectors, Shack–Hartmann and pyramid wavefront sensors, back-focal-plane split detection, and finite pixel arrays. A quadrant photodetector (QPD) provides an analytically tractable case. Starting from the complete two-dimensional power integrals, we identify the spatial-moment origin of its lowest-order cross term. Axis calibration and system symmetry then constrain the inverse map, giving Axis-Anchored Cross-Residual Inversion (ACRI). Numerical tests of this QPD realization support the sensitivity relations and show that the constrained cross correction substantially reduces the off-axis bias retained by single-axis inversion. The results illustrate how the general measurement representation guides inverse construction, with performance bounded by the working domain, calibration state, and preserved symmetries.
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Instrumentation and Detectors

Characterization and Active Control of Position-Dependent Timing Dynamics in Superconducting Strip Single-Photon Detectors

Sahil R. Patel, Kristen M. Parzuchowski, Eli Mueller et al. (+6 more)

Superconducting strip single-photon detectors (SSPDs) have emerged as scalable, wide-strip variants of traditional nanowire counterparts. Despite practical advantages including improved optical fill factors and enhanced signal-to-noise ratios the fundamental detection physics governing these micro-scale geometries remains largely unexplored. Here, we investigate the underlying photoresponse of a 20 um-wide tungsten silicide SSPD, demonstrating a slew-rate-corrected timing jitter of 13.2 ps at 532 nm and 20.5 ps at 1550 nm, alongside saturated internal detection efficiency up to 1550 nm. Using focused free-space optical scanning, we reveal that detector timing jitter is strongly influenced by a spatially dependent slew rate between edge and center absorption events. To mitigate this impact, we utilize a parallel superconducting rail architecture to actively redistribute supercurrent. This in-situ tuning minimizes the latency mismatch and mitigates thermally activated intrinsic dark counts, extending the device's ability to operate at higher temperatures. Finally, comparing these dynamics with time-dependent Ginzburg-Landau (TDGL) modeling elucidates the physical origins of the position-dependent photoresponse, highlighting how superconducting rails or specialized readout electronics can mitigate negative impacts on timing jitter.
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All authors Sahil R. Patel, Kristen M. Parzuchowski, Eli Mueller, Boris Korzh, Emanuel Knehr, Adam N. McCaughan, Martin J. Stevens, Matthew D. Shaw, Jason P. Allmaras

Wednesday 23 September

Instrumentation and Detectors

Performance of the MPD experiment in dielectron measurements at NICA

Sudhir Pandurang Rode, Itzhak Tserruya, Victor Riabov et al. (+2 more)

The Multi-Purpose Detector (MPD) experiment at NICA is designed to investigate strongly interacting matter at high net-baryon density through a broad program of heavy-ion measurements. Dielectrons constitute one of the key probes in this program, with contributions emitted throughout the entire space-time evolution of the collision. Their experimental measurement is, however, challenged by a large combinatorial background arising primarily from incompletely reconstructed photon conversions and Dalitz decays of light neutral mesons. In this work, we study the performance and capabilities of the MPD experiment for dielectron measurements using simulated minimum-bias $^{209}$Bi+$^{209}$Bi collisions at $\sqrt{s_{NN}}$ = 9.2 GeV. Electron identification is performed using the combined information from the TPC, the TOF detector and the ECal. A multilayer-perceptron classifier is used to optimize electron identification, leading to a substantial increase in electron detection efficiency relative to sequential one-dimensional selections while preserving an electron-sample purity close to unity over a broad momentum range. To address the dominant sources of combinatorial background, a pair-analysis strategy is developed that exploits partially reconstructed electron tracks. The method combines the pair opening angle, the TPC dE/dx signal, and an approximate reconstruction of the pair invariant mass to tag tracks from photon conversions and $\pi^0$ Dalitz decays at the pair level. In the mass interval 0.2 $< m_{ee}<0.7 $ GeV/$c^2$, the method improves the signal-to-background ratio by a factor of about 3.5 with the current track reconstruction algorithm. The study demonstrates the strong potential of the MPD experiment for dielectron measurements at NICA energies and highlights the importance of further improvements in low-$p_{\rm T}$ track reconstruction.
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All authors Sudhir Pandurang Rode, Itzhak Tserruya, Victor Riabov, Yonghong Wang, Chi Yang

Instrumentation and Detectors

Cross-geometry transfer and model collapse in point cloud calorimeter shower generation

Thorsten Buss, Frank Gaede, Gregor Kasieczka et al. (+2 more)

Particle shower simulation is a major computational cost in high-energy physics. Monte Carlo methods such as Geant4 are accurate but expensive, while most machine learning surrogates are tied to specific detector geometries and require retraining for each design change. We study cross-geometry transfer learning with CaloClouds II, a generative model that produces point clouds rather than voxels and can project onto arbitrary detector readouts. We pre-train on photon showers in the International Large Detector (ILD) and adapt to electron showers in the cylindrical CaloChallenge Dataset 3. With only 100 target showers, fine-tuning reduces the geometric mean Wasserstein distance to Geant4 by about 51% over training from scratch. Bias-only fine-tuning (BitFit) stays within 5% of full fine-tuning while updating only 17% of the diffusion network parameters. We also examine model collapse in CaloClouds II by retraining its normalising flow and diffusion model on its own generated showers across successive generations.
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All authors Thorsten Buss, Frank Gaede, Gregor Kasieczka, Lorenzo Valente, Duncan Weber

Instrumentation and Detectors · Cross-listed from cs.LG

Physics-Informed Self-Supervised Learning for Joint Wire Calibration and Interaction Position Reconstruction in Multi-Wire Parallel Plate Avalanche Counters

Antoine Lemasson and Maurycy Rejmund

Scientific instruments require accurate calibration to convert detector signals into reliable physical observables. Conventional calibration procedures typically rely on dedicated calibration measurements, analytical response models or labelled reference data, limiting their ability to adapt to changing operating conditions and detector aging. We present a physics-informed self-supervised learning framework that jointly performs wire calibration and interaction position reconstruction in Multi-Wire Parallel Plate Avalanche Counters (MWPPACs) without requiring labelled position measurements or dedicated calibration runs. The method formulates detector calibration as a latent optimization problem in which global wire gains and event-wise interaction positions are estimated simultaneously using supervision derived exclusively from detector geometry and charge-energy consistency constraints. A detector-independent neural network reconstructs sub-wire interaction positions from local charge distributions, eliminating the need to assume analytical induction profiles by learning the detector response directly from experimental data. The end-to-end differentiable framework enables continuous detector self-calibration while improving the uniformity and accuracy of position reconstruction. Experimental evaluation on the entrance MWPPAC tracking detectors of the VAMOS++ magnetic spectrometer demonstrates stable convergence, improved spatial homogeneity and enhanced position resolution. Beyond the detector studied, the method establishes a general framework for physics-informed self-supervised calibration of scientific instruments and is a step toward autonomous intelligent instrumentation capable of continuous adaptation during operation. In this paradigm, detector calibration is no longer a prerequisite for an experiment but an integral part of the measurement process itself.
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Instrumentation and Detectors

Fast-Neutron Scintillation with Multi-Quantum-Well 2D Perovskites

Shaun Tan, Zachary Benesh, Seong Eui Chang et al. (+4 more)

Fast-neutron scintillators must efficiently convert neutron energy into detectable light while enabling selectivity between neutrons and the {\gamma}-ray background. Here, we report a synthesis strategy for layered two-dimensional (2D) lead halide perovskite scintillators with independent control of the macroscopic detector geometry and microscopic phase composition. Our synthesis approach produces mm-thick, large-area scintillators with a deliberately engineered multi-quantum-well energy landscape, creating an effective spectral separation while retaining nanosecond emission dynamics. Our scintillators exhibit an energy resolution of 5.4% at 662 keV under 137Cs irradiation. Under deuterium-deuterium fusion neutron irradiation, we directly demonstrate neutron and {\gamma}-ray event separation by pulse shape discrimination, with a figure of merit of 3.51. Taken together, these results establish multi-quantum-well 2D perovskites as a scalable materials platform that combines fast-neutron sensitivity and selectivity within a controllable detector form factor.
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All authors Shaun Tan, Zachary Benesh, Seong Eui Chang, Shelby Elder, Haidi Jakovic, Tae-Woo Lee, Moungi G. Bawendi

Instrumentation and Detectors

Study of the properties of sustainable materials for shielding against ionizing radiations

Julien Faivre

The SuShi project aims at determining how sustainable materials can be used to shield against ionizing radiations. This contribution presents a comparison of the effect of concrete and rammed raw earth on photons. For energies around the MeV, where interactions by Compton scattering dominate, changes in the material composition have virtually no effect. The density difference results in 20% more thickness needed for earth to achieve the same flux attenuation as concrete. The same value is found for higher energies, where photons produce electromagnetic showers. Below 0.1 MeV, material composition and earth moisture content matter but the attenuation is much larger.
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Instrumentation and Detectors

CBM T0 Detector Performance Study with Light Ions (4He, 12C) and the DOGMA Readout System

Yevhen Kozymka, Thomas Bergauer, Maximilian von Buelow et al. (+14 more)

This paper presents the realization and performance of the CBM T0 detector system. Built upon an approximately 70 {\mu}m thin polycrystalline CVD (pcCVD) diamond sensor with pad metallization, the detector is mounted on a flexible vacuum manipulator and operates entirely under passive cooling. Interfaced with the DOGMA readout architecture, the system successfully meets all operational requirements for CBM. It demonstrates a high detection efficiency (near 100%) and a timing precision below 50 ps RMS across a broad range of beam species, from light ions (such as Carbon) to heavy ions (such as Gold). The DOGMA readout features two distinct data paths: a high-precision TDC path routing data directly to the global CBM DAQ, and a secondary path deliver in real-time rate measurements crucial for online beam quality monitoring and fast beam abort logic. Finally, detailed performance studies conducted with light-ion beams at EBG MedAustron are discussed.
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All authors Yevhen Kozymka, Thomas Bergauer, Maximilian von Buelow, Henrik Flörsheimer, Jochen Frühauf, Tetyana Galatyuk, Harald Handerkas, Henning Heggen, Mladen Kis, Sergey Linev, Jerzy Pietraszko, Christian Joachim Schmidt, Luca Schramm, Michael Traxler, Michael Träger, Felix Ulrich-Pur, Robert Visinka

Instrumentation and Detectors

Cryogenic performance and long-term stability of Hamamatsu R8520-506 photomultiplier tubes in liquid argon

Jilong Yin, Gaoshuang Li, Yike Shu et al. (+1 more)

Seven Hamamatsu R8520-506 photomultiplier tubes were characterized at room temperature and in liquid argon to evaluate their response and operating stability for liquid-argon light readout. A 405~nm pulsed light source was used to measure gain, peak-to-valley ratio, single-photoelectron charge resolution, and afterpulsing, while dark-count data were acquired with random triggers in the absence of active illumination. Gain and dark-count stability were monitored during a ten-day operating period in liquid argon. At a motherboard input voltage of 900~V, the extracted gains in liquid argon were approximately 27.8%–51.3% higher than the corresponding room-temperature values. For all seven tubes, the peak-to-valley ratios were higher and the single-photoelectron charge resolution improved in liquid argon. The dark count rates ranged from approximately 143 to 252~Hz at room temperature and from 166 to 199~Hz in liquid argon, with three tubes showing increases and four showing decreases. The mean number of detected afterpulses per selected primary event was approximately 21.0%–63.6% lower in liquid argon. The relative standard deviations across the ten daily means of gain and dark count rate did not exceed approximately 2.1% and 3.3%, respectively. The measurements provide a quantitative basis for considering R8520-506 tubes as photosensor candidates for liquid-argon detectors.
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All authors Jilong Yin, Gaoshuang Li, Yike Shu, Yi Wang

Instrumentation and Detectors

kicad-pycbnew: A Python Framework for Automated, High-Precision PCB Design in Particle Detector Instrumentation

Vincent Raspal

kicad-pycbnew is an open-source Python library for the automated, script-based generation of KiCad PCB designs, tailored to the precise geometric and impedance constraints of particle detector readout electronics. By enabling the programmatic definition of copper traces, zones, vias, and footprints — without a graphical interface — it addresses the challenges of designing large-scale, repetitive, or parameterized layouts (e.g., Resistive Plate Chamber (RPC) strips or controlled-impedance signal paths). Key features include constraint-driven routing, parallel track arrays with rounded corners, via grids with exclusion zones, and full compatibility with KiCad's native file format. Standalone operation (no KiCad runtime required) facilitates integration into CI/CD pipelines and ensures reproducibility. The library, released under the MIT License, includes validated examples such as trapezoidal RPC readout boards and extension boards for the COMET experiment, alongside comprehensive tests and documentation.
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Tuesday 22 September

Instrumentation and Detectors

Meta-learning accelerates detector design optimization

Maxim Borisyak, Nikita Gladin and Andrey Ustyuzhanin

The quality of a detector design is ultimately determined by the quality of the inference it enables, that is, by the accuracy with which the quantities of interest are reconstructed from the raw detector response. For complex detectors, the inference is performed by machine learning models, and the relation between the design and the attainable inference performance is, in general, non-trivial. In this work, we consider the optimization of the inference performance with respect to the detector design. The conventional approach prescribes retraining the inference model at every candidate design, thus, treating the evaluations as independent tasks and discarding the shared structure of the optimal inference algorithms at different designs. We propose the meta-learned objective estimate (MLOE): instead of solving the inference problem anew at every candidate design, a single meta-inference model, conditioned on the design and trained continually along the optimization path, is shared across all of them. We test MLOE on three families of optimization problems, the last of which comprises two design spaces of the Spectrometer Straw Tracker of the Search for Hidden Particles (SHiP) experiment; under matched budgets of simulation calls, the meta-inference model evaluates a candidate design using fewer simulation calls than the baseline strategies and holds the better rank over the convergence curve in all examined cases.
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Instrumentation and Detectors

A Scalable Stacked-Electrode Printed Circuit Board Radio-Frequency Quadrupole (PCB-RFQ) for Precision Experiments

Tayemar K. Fowler-Davis, Moritz Pascal Reiter, Nawaf Altasan et al. (+21 more)

Linear radio-frequency quadrupole (RFQ) traps are crucial for ion and phase-space manipulation across diverse physics platforms, including quantum information processing, precision atomic spectroscopy, and high-resolution mass or laser spectrometry. We present the design, electrostatic field optimization, and performance characterization of a scalable, multi-layer printed circuit board (PCB) linear RFQ trap. By utilizing a PCB-based "stacked-electrode" geometry to generate high-quality quadrupolar fields, this architecture suppresses higher-order multipole field components by up to an order of magnitude compared to planar "flat surface-electrode" designs and allows for reclaiming up to 60% of the radial pseudopotential-well depth of an ideal hyperbolic quadrupole. Following a thorough optimisation and characterization using both simulations and experiments, we demonstrate its suitability as a cooler buncher, showing rapid helium buffer-gas cooling with time constants between 34 +/- 3 us and 412 +/- 23 us, and achieving a highly compressed longitudinal phase-space emittance of only 58 +/- 4 eV*ns. The low beam emittance provides flexible control of the extracted bunch properties: weak extraction fields yield energy spreads down to 2.5 +/- 0.4 eV, whereas strong fields produce ultra-narrow temporal widths down to 2.6 +/- 0.3 ns. The results establish our PCB-RFQ platform as a versatile, scalable, and cost-effective alternative to traditionally machined rod-based RFQ assemblies for advanced ion-trapping, beam-preparation, or quantum applications.
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All authors Tayemar K. Fowler-Davis, Moritz Pascal Reiter, Nawaf Altasan, Samuel Ayet San Andrés, Peter Black, Jason Breyiannis, Callum L. Brown, Peter Dasiukevich, Adam Zaki Davies, Timo Dickel, Oscar Hall, Alexandru Hau, Jamie C. Jones, Jan Kocka, Gabriella Kripkó-Koncz, Konrad Linkowski, Adam J. McCarter, Sophia Scrimshaw, Joe Simon, Jack Lee Smith, Wolfgang R. Plaß, Gemma Robertson, Jiajun Yu, Alexandra Zadvornaya