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Physics Physics Instrumentation and Detectors

physics.ins-det Watch Instrumentation and Detectors

Friday 2 October

Instrumentation and Detectors

Application of sequence learning for predicting radiation damage of the CMS electromagnetic calorimeter

Mario Ivan Gallegos Torres, Leonid Serkin and Guy Paic

In this paper we use machine learning methods to predict radiation damage in the lead tungstate crystals of the CMS electromagnetic calorimeter at the Large Hadron Collider. We analyze LHC Open Data collected from 2016 to 2018 and study the time evolution of the crystal optical transparency. We apply deep neural network models to predict its behavior over different future time intervals, and find that encoder-decoder sequence-to-sequence architectures can effectively describe crystal aging.
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Instrumentation and Detectors · Cross-listed from cond-mat.str-el

ToF-PAX-RIXS: A Time-of-Flight Spectrometer for combined ARPES and RIXS

Chafic Fawaz, Tom Lacmannn, Yaryna Lytvynenko et al. (+24 more)

We present ToF-PAX-RIXS, a compact instrument that combines time-of-flight momentum-microscopy angle-resolved photoemission spectroscopy (ARPES) with resonant inelastic X-ray scattering (RIXS). The latter is based on photoelectron spectrometry for analysis of X-rays (PAX). The two techniques are implemented with a single multimode electron-optical column, allowing measurements to be performed sequentially on the same sample under identical experimental conditions. In ARPES mode, the instrument records the photoemission intensity as a function of kinetic energy and two in-plane momentum components. In PAX-RIXS mode, scattered soft X-ray photons are absorbed in a thin metallic converter, and the generated photoelectrons are analyzed in energy and position of emission on the converter. The electron kinetic energy retains the spectral information of the scattered photons, while the position is related to the scattering angle and therefore to the momentum transfer, enabling simultaneous access to a finite momentum-transfer interval. We describe the mechanical design, converter assembly, scattering geometry, and multimode electron optics of the instrument. Its PAX-RIXS performance is benchmarked at the Cu $L_3$ edge using CaCuO$_2$, with Au, Ag, and Pt converters. The measured spectra reproduce the principal features obtained with a conventional grating RIXS spectrometer, and deconvolution yields an effective reconstructed energy resolution better than $120$~meV under the present conditions. Finally, combined ARPES and PAX-RIXS measurements on the same Ca-doped YBa$_2$Cu$_3$O$_{6.45}$ sample demonstrate the capability of the instrument to correlate electronic structure and collective excitations within a common compact platform.
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All authors Chafic Fawaz, Tom Lacmannn, Yaryna Lytvynenko, Sergii Chernov, Olena Tkach, Siegmar Roth, Jan O. Schunck, Amon Lanz, Jakob Dilling, Lukas Bruckmeier, Markus Scholz, Frank Scholz, Arne Meyer, Dirk Fuchs, Lara Schmieder, Yiran Liu, Matteo Minola, Bernhard Keimer, Dmytro Kutnyakhov, Kai Rossnagel, Olena Fedchenko, Angela Wittmann, Moritz Hoesch, Gerd Schönhense, Matthieu Le Tacon, Hans-Joachim Elmers, Martin Beye

Instrumentation and Detectors · Cross-listed from cs.AI

NeutronGym: Physics-Graded Neutron Instrument Design for LLM Agents

Lijie Ding and Changwoo Do

Designing a scientific instrument tests whether language-model agents can do physics rather than recall it, provided the grading cannot be argued with. We introduce NeutronGym, to our knowledge the first executable environment for neutron instrument design: agents build instruments through validating tools, McStas ray-traces what they build, and a level-resolved ladder grades syntax, runtime, structure and science with no LLM judge. Procedural families supply unlimited instances of a fixed layout whose design parameters the agent must set, with held-out parameter regimes; a curated slice, McStasBench, adds 16 tasks from published instruments behind memorization probes and a sandbox. Seven models reproduce at most 7 of the 16, none retrieves a reference, and none meets an improvement target. The environment also trains. Reinforcement learning on its reward takes Qwen3-8B from 11% to 77% of held-out instances of a family whose targets come from a hidden design (69% at a second seed), past an untrained Qwen3-32B, and the recipe holds, at one seed each, on three further gated families. The analysis says what that gain is. Without the ladder's partial credit it collapses by 60 points. From reward alone the trained model reaches what a classical optimizer reaches, at the agent's simulation budget, only when handed the closed-form physics (77% against 81%, a gap that does not separate at this size), while frontier models still solve 98-99%. Getting a trustworthy result meant failing four task designs that no-model baselines could solve, and we release the probes that found them.
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Instrumentation and Detectors · Cross-listed from quant-ph

The QICK Box: A Modular RF Front-End System for Quantum Control and Readout

L. Arnaldi, D. Martin, S. Sussman et al. (+11 more)

The QICK (Quantum Instrumentation Control Kit), first introduced in 2022, is a standalone open source control system for quantum information science. Since then, QICK has been migrated to new hardware platforms, expanded its functionality for applications with different types of qubits (superconducting, atomic, ion-trapped, and spin defects), as well as quantum sensors, and quantum networks. QICK is a highly optimized control kit, with a library of functions that can be used for more than one application. In particular, the software and firmware are customized to minimize latency and maximize control performance and throughput. In this white paper, we describe hardware details and performance of the QICK Box. The QICK Box features up to 16 outputs, up to 8 inputs, and 8 20-bit DC biases. Modular output and input daughtercards give the choice of signal chains optimized for fast DC-coupled signals or RF signals up to 10 GHz. Power levels, step attenuation, and bandpass filtering are controlled by software. We demonstrate the system's performance through single-shot readout measurements of a six-transmon device at the Quantum Underground Instrumentation Experimental Testbed (QUIET) at Fermilab, achieving (91.7 +/- 0.4)% readout fidelity limited by T1 decay during the readout. The single shot readout signal-to-noise ratio (SNR) is 4.4 +/- 0.1 without a quantum amplifier, confirming that the QICK Box is suitable for high-fidelity quantum control and measurement applications. Advances in firmware and software will be described in a separate paper.
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All authors L. Arnaldi, D. Martin, S. Sussman, S. Uemura, K. Treptow, N. Wilcer, A. Colón Cesaní, O. Seidel, K. Anyang, G. Bratrud, F. Abouzahr, J. Christiansen-Salameh, D. Baxter, G. Cancelo

Instrumentation and Detectors

Controlled-illumination smartphone imaging for quantitative turbidity measurement and cross-device transfer

Sebastian Olivares, Addles Castillo, Patricia Velasquez et al. (+2 more)

Smartphone imaging could provide a low-cost turbidity measurement method if illumination and acquisition geometry are controlled. We evaluated a 3D-printed enclosure with fixed illumination and a submerged optical target using 162 milk-based suspensions spanning 0.16–50.2 nephelometric turbidity units (NTU), with a portable turbidimeter as the reference. An EfficientNetB0 regression model evaluated using repeated five-fold grouped cross-validation achieved a mean absolute error (MAE) of 1.208 NTU and $R^2=0.9816$, indicating that predictions followed the reference measurements closely. The MAE was 0.335 NTU below 1 NTU and 0.449 NTU from 1 to below 5 NTU; classification accuracy at the operational 5-NTU threshold was 0.9753. When applied without retraining to 103 paired images from a second smartphone, prediction error remained comparable to that on the development smartphone below 10 NTU, but turbidity was increasingly underestimated at higher values. The results demonstrate the measurement performance attainable with a controlled smartphone acquisition system, quantify an important device-dependent transfer limitation, and motivate standardized multi-device acquisition and prospective natural-water validation.
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All authors Sebastian Olivares, Addles Castillo, Patricia Velasquez, Roxana Arce, Nicolas Richardson

Instrumentation and Detectors

Residual AM and PM Noise of Selected X-Band Amplifiers

Archita Hati, Craig Nelson and Scott Littrell

In microwave systems design, amplitude modulation (AM) noise is often ignored relative to phase modulation (PM) noise. However, in high-performance applications requiring ultra-low PM noise, AM noise becomes a critical limiting factor due to AM-to-PM conversion mechanisms. Because AM noise specifications are rarely, if ever, provided for commercial microwave components, this study characterizes the residual AM and PM noise of several 10 GHz amplifiers. We present performance data for various Heterojunction Bipolar Transistor (HBT) amplifier designs and demonstrate the noise reduction achieved through power-summed configurations. For example, a discrete-die GaAs HBT amplifier achieves residual PM noise below $-160$ dBrad$^2$/Hz and AM noise of approximately $-155$ dB/Hz at a 1 kHz offset in a quad power-summed configuration. A notable finding is that the majority of amplifier designs surveyed in this study exhibit higher AM noise relative to their PM noise, with only a few exceptions. The impact of bias supply quality on residual noise is also quantified, demonstrating that the choice of voltage regulator is a first-order design parameter below 1 kHz offset.
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Instrumentation and Detectors · Cross-listed from hep-ex

First measurement of the low-momentum negative-muon beam for the muon-to-electron conversion experiment at J-PARC

The COMET Collaboration: K. Oishi, R. Abramishvili, G. Adamov et al. (+182 more)

The COMET Phase-$\alpha$ experiment, the initial beam-operation stage of the COMET muon-to-electron conversion programme at J-PARC, took place in 2023 and marked the first beam operation at the COMET facility. It served to commission the delivery of a bunched, slow-extracted 8 GeV proton beam and the muon beamline. Its objective was to demonstrate experimentally that low-momentum negative muons could be transported to the experimental area through the Transport Solenoid (TS). We report a measurement of the transported muon beam using the Range Counter, a dedicated detector that identifies stopped negative muons by detecting delayed electrons emitted after the muons stop in a copper absorber. From the measured decay-time spectra, we reconstruct the number of stopped muons, the corresponding momentum spectrum, and the transverse beam profile. The observation of the stopped-muon component demonstrates that slow negative muons were transported through the TS to the experimental area. The reconstructed momentum spectrum indicates that the transported beam is concentrated in the low-momentum region. The non-uniform transverse profile is qualitatively consistent with charge drift in the curved solenoidal magnetic field. A Geant4-based simulation reproduces the overall dependence on degrader thickness and detector position; the measured yields are systematically higher by roughly 30%. These results provide the first experimental benchmark of low-momentum negative-muon transport in COMET and establish the basis for future beam characterisation and production studies.
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All authors The COMET Collaboration: K. Oishi, R. Abramishvili, G. Adamov, J. C. Angelique, K. Aoki, M. Aoki, Y. Arimoto, A. N. B. Az, I. Bagaturia, D. Bauer, T. Bouillaud, L. Del Buono, C. Cârloganu, N. Chadeau, Y. Chen, P. Chetry, D. Chokheli, T. Clouvel, P. D. Dauncey, S. Dekkers, R. Derveni, G. Devidze, P. J. Dornan, M. T. Dubouchet, L. B. Epshteyn, I. Evtoukhovitch, P. Evtoukhovitch, G. Faure, S. Fayer, G. V. Fedotovich, Y. Fujii, Y. Fukao, E. George, E. L. Gillies, M. Gouzevitch, D. N. Grigoriev, E. Hamada, I. H. Hashim, S. Hashimoto, M. Higashide, Y. Higuchi, N. Hiroshima, Y. Igarashi, F. V. Ignatov, M. Iio, M. Ikeno, K. Ishibashi, T. Itahashi, A. Jansen, R. Jeena, O. Jeremy, X. Jiang, P. M. Jonsson, Y. Kageyama, V. Kalinnikov, E. Kaneva, F. Kapusta, K. Kawagoe, R. Kawashima, N. Kazak, A. Khvedelidze, Y. Kojima, A. N. Kozyrev, B. Krikler, Y. Kuno, S. Kuribayashi, Y. Kurochkin, N. Kurosawa, A. Kurup, K. Ladhams, P. Lebrun, M. J. Lee, H. Li, W. Li, R. P. Litchfield, D. Lomidze, I. Lomidze, G. Macharashvili, Y. Makida, S. Makimura, G. Matsumoto, S. Matsumoto, A. Melnik, H. Miao, S. Mihara, A. Miles, M. Miyataki, Y. Miyazaki, T. Mizuno, M. Moritsu, R. Muto, R. Nagai, H. Nagashima, Y. Nakai, T. Nakamoto, Y. Nakamura, Y. Nakatsugawa, Y. Nakazawa, J. Nash, M. A. S. Nasrullah, T. M. Nguyen, V. Niess, Y. S. Ning, H. Nishiguchi, M. Nishihara, K. Noguchi, N. H. M. Nor, N. Norjoharuddeen, T. Ogitsu, H. Ohata, N. Ohuchi, K. Okabe, T. Okamura, H. Okurano, M. Oonaka, J. Pasternak, A. Paulau, D. Pieters, V. Raspal, R. Razali, A. Razquin, W. Roth, B. Sabirov, T. Saito, H. Sakamoto, P. Sarin, K. I. Sasaki, R. Sasaki, A. Sato, J. Sato, H. Sendai, N. Shigyo, M. Shinjo, Z. Shioya, M. Shoji, Dz. Shoukavy, W. Da Silva, A. Simonenko, D. Stöckinger, N. Sumi, A. Sumimura, S. Sun, J. Suzuki, S. Takami, S. Tanaka, J. Tang, J. Tojo, M. Tomizawa, T. Toriashvili, N. Tran, Z. Tsamalaidze, N. Tsverava, T. Uchida, Y. Uchida, Y. Uchiyama, S. Ueda, K. Ueno, Y. Uesaka, D. Vasileuskaya, E. Velicheva, M. L. Wong, T. S. Wong, C. Wu, T. Xing, Y. Xu, C. Yamada, H. Yamaguchi, M. Yamanaka, Y. Yang, W. Yao, B. Yeo, H. Yoshida, M. Yoshida, M. Yoshii, D. Yoshikawa, T. Yoshioka, Y. Yuan, Yu. V. Yudin, N. Yussup, I. Yusuff, J. Zhang, Y. Zhang, Z. Zhang, Y. Zhou, K. Zuber

Instrumentation and Detectors · Cross-listed from quant-ph

Optimal state detection without likelihood estimation

M. D. K. Lee, Z. Chai, J. Z. F. Seng et al. (+2 more)

We show that adaptive Bayesian estimation in fluorescence state detection reduces to a comparison of elapsed time with two arithmetic time sequences fixed by the bright and dark count rates and confidence parameters $\epsilon_d$ and $\epsilon_b$. No probabilities are computed in real time and the resulting implementation, which we term sequential deadline detection, is provably optimal in mean detection time. The analysis permits closed-form expressions for detection-time distributions, mean detection times, error rates of both channels accounting for miscalibrated rates, decay between the states during detection, and afterpulsing in single photon counting modules. The predictions are validated by Monte Carlo simulation and demonstrated by fluorescence detection with Ba$^+$
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All authors M. D. K. Lee, Z. Chai, J. Z. F. Seng, K. J. Arnold, M.~D.~Barrett

Thursday 1 October

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

A Student Sounding Rocket Experiment to Probe Electron Density in the Lower Ionosphere

Joshua Goodwill, Timothy Tomaszewski, Jarrod Bieber et al. (+17 more)

Earth's ionosphere is primarily generated by the Sun's ionization of atoms in the upper atmosphere. This plasma environment is highly dynamic, exhibits strong spatial and temporal, variations and significantly impacts power systems, navigation, and satellite and ground communications. The University of Delaware Ionospheric Probe (UDIP) was developed as a hands-on learning experience for University of Delaware students on the ionosphere itself and on the development of space technology. Students (mostly undergraduates) have led all aspects of the experiment including mission planning, electronics development, mechanical development, software development, and scientific data analysis. The present study is intended as a guide to readers on how the development of space and near-space flight missions can be successfully incorporated into an undergraduate physics curriculum. The fourth version of the experiment (UDIP-4) flew along with student experiments from across the USA on the 2024 RockSat-C sounding rocket, which was launched from NASA Wallops Flight Facility. During the flight, UDIP-4's Langmuir probe successfully measured the ionosphere's density profile – electron density as a function of altitude – up to an apogee of 114 km. Though the measured density profile agrees well overall with the predictions of theoretical models, UDIP-4 identified a thin layer of enhanced electron density at an altitude of approximately 110 km that is consistent with a sporadic E layer.
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All authors Joshua Goodwill, Timothy Tomaszewski, Jarrod Bieber, Carson P. Brown, Ashton Southwick, Samuel Auerbach, Sreenidhi Banda, Alex Bruce, Marisol Catalan Olais, Markos Duey, Ranyah Khan, Connor McCleery, Jonathan Rosado, Amanda Swenson, Matthew Ward, Jarod Dagney, David Sundkvist, John W. Bonnell, William H. Matthaeus, Bennett A. Maruca

Instrumentation and Detectors

State of the Art in Direct Dark Matter Detectors: Technologies, Performance, and Future Directions

Muad Ghaith and Khaled Obaideen

Identifying the particle nature of dark matter remains one of the most significant challenges in modern physics. Direct detection experiments aim to observe rare scattering events between dark matter particles and terrestrial targets, a task that demands extreme background suppression and sensitivity to minute energy depositions. This review critically assesses the current experimental landscape, organizing detector technologies by the fundamental physical trade-offs that define their scientific reach. We contrast the multi-tonne scalability of noble-liquid Time Projection Chambers (TPCs), which currently define the sensitivity frontier for high-mass Weakly Interacting Massive Particles (WIMPs), with the precision of cryogenic semiconductors and Charge-Coupled Device (CCD)- based sensors, which dominate the search for low-mass and sub-GeV candidates. Special emphasis is placed on the role of advanced reconstruction pipelines and machine learning (ML) as integral components of detector performance. Finally, we discuss the strategic roadmap for the next decade as experiments approach the neutrino fog, where coherent elastic neutrino-nucleus scattering (CE{\nu}NS) produces an increasingly significant and ultimately irreducible background that can mimic DM-induced nuclear recoils. We argue that future progress will rely not on a single technology but on a complementary global program combining increased target mass, ultra-low energy thresholds, improved background discrimination, and distinct observables - such as directionality and temporal signatures - to maintain robust discovery capability in the presence of neutrino-induced backgrounds.
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Instrumentation and Detectors · Cross-listed from astro-ph.SR

Towards solar many-line inversions

Johannes Hölken

The Sun's atmosphere is significantly influenced by events that often measure only tens of kilometres in the horizontal direction. They happen in both quiet and active regions and are determined by magneto-hydro-dynamic processes. Their origins often lie in the lowest layers of the solar atmosphere. To improve the understanding of chromospheric and coronal heating, the solar dynamo and its activity cycle, or to improve the prediction of space weather events we must therefore enhance our understanding of such small-scale events. In this work I first describe the process of calibrating spectropolarimetric observations with very high spatial resolution and put together the building blocks for the mathematical proof the MOMFBD image reconstruction algorithm. In the second part I describe the FISS-SP prototype which is designed to fully exploit the resolution power of a 1.6m telescope. This instrument is built to provide suitable data for image reconstruction of spectropolarimetric data. The resulting data can resolve small-scale features down to the diffraction limit. The simultaneous interpretation of a few lines is still the norm for spatially highly resolved solar spectra. Theoretical works have shown that the simultaneous interpretation of multiple solar lines can greatly improve the robustness against noise. Using observations from FISS-SP I advance the theoretical idea into a practical technique. With this I can retrieve a coherent model of the local solar atmosphere, resolving structures down to a horizontal size of about 49~km. Finally, I use those new techniques to interpret an observation of a solar pore. In this last part I describe and analyse small-scale structures, which could not be spectropolarimetrically resolved before. Typical pore-boundary features - namely, dark striations with bright grains moving into the pore - are identified as convective features.
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Wednesday 30 September

Instrumentation and Detectors

Impact of Gain Layer Doping Concentration on the Performance of 4H-SiC LGADs

Tao Yang, Ben J. Sekely, Yashas Satapathy et al. (+12 more)

Gain layer doping concentration determines the electric field profile in a low gain avalanche detector (LGAD) and is therefore the primary design parameter. This work reports its influence on the charge collection and timing behavior of 4H-SiC LGADs. Two mesa-isolated devices with cold He ion implanted termination differ only in gain layer doping, $4\times10^{17}$~$cm^{-3}$ and $5\times10^{17}$~$cm^{-3}$, and are characterized together with a PIN diode from the same wafer using the ultraviolet transient current technique (UV-TCT). The 25% doping difference produces a gain difference of about two orders of magnitude at the same applied bias, representing a gain range of 3.7 to 216. Under UV-TCT excitation, the higher-doped device exhibits time-resolution minima within a gain range of about 20–80 across the investigated laser intensities, consistent with the transition from electronic-noise-dominated jitter to multiplication shot noise. The non-monotonic timing response is also observed under a $^{90}Sr$ beta source with a Si LGAD reference: the higher-doped device reaches 51.7 ps at 280 V and then degrades, while the lower-doped device requires more than 450 V. This measured gain window provides an experimental reference for further optimization of the gain-layer design.
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All authors Tao Yang, Ben J. Sekely, Yashas Satapathy, Abraham Tishelman-Charny, Greg Allion, Gil Atar, Philip Barletta, Gabriele Giacomini, Carl Haber, Steve Holland, John F. Muth, Spyridon Pavlidis, Chengxi Yang, Haichen Wang, Stefania Stucci

Instrumentation and Detectors

Performance and quality testing of CBM RICH front-end electronics

Pavish Subramani, Christian Pauly, Joerg Foertsch et al. (+2 more)

This note describes the laboratory setup at the University of Wuppertal and its use to measure charge sharing crosstalk, perform high rate and high occupancy tests of MAPMT-DIRICH readout elec- tronics using a realistic detector setup, and also includes the analysis of induced electronic noise characteristics of a new iteration of the DIRICH power module to be used in the CBM RICH readout chain.
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All authors Pavish Subramani, Christian Pauly, Joerg Foertsch, Dennis Pfeifer, Karl-Heinz Kampert

Instrumentation and Detectors

Measurement of the $^{39}$Ar specific activity in atmospheric argon with DArT at the Canfranc Underground Laboratory

P. Agnes, H. O. Back, S. Bharat et al. (+41 more)

We report the measurement of the $^{39}$Ar specific activity of atmospheric argon using DArT, a low-background single-phase liquid-argon detector read out by cryogenic silicon photomultipliers, at the Canfranc Underground Laboratory (LSC) in Spain. DArT was first filled with atmospheric argon and then with a sample of underground argon of known radioactivity from the DarkSide-50 experiment. The underground argon serves as a background reference in this measurement, making the result robust because we do not rely on background simulations. We measure the $^{39}$Ar specific activity with both a cut-and-count method and a binned maximum-likelihood fit, yielding consistent results. We obtain $a_{\text{AAr}}= 0.955 \pm 0.008~\text{Bq}/\text{kg}$. This result agrees with previous measurements from other experiments and provides the most precise determination of the $^{39}$Ar specific activity in atmospheric argon to date. It also validates DArT as a key component of the DArTInArDM experiment at LSC, which aims to measure the $^{39}$Ar activity of the argon extracted from deep underground wells in Colorado (USA) for the Darkside-20k and LEGEND-1000 experiments at Laboratori Nazionali del Gran Sasso in Italy.
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All authors P. Agnes, H. O. Back, S. Bharat, W. M. Bonivento, M. Boulay, M. Caboni, N. Canci, N. Cargioli, P. Castello, S. Cebrián, L. Consiglio, R. Crampton, D. Diaz Mairena, D. Franco, I. Fuente-Ortega, F. Gabriele, D. Gahan, C. Galbiati, P. Garcia Abia, T. Hessel, S. Horikawa, A. Ianni, G. Korga, M. Kuźniak, L. Luzzi, A. Marasciulli, M. Martínez, P. Organtini, A. Ortiz de Solórzano, R. Pavarani, P. Pegoraro, V. Pesudo Fortes, M. Razeti, O. U. Rehman, L. Romero, D. Sablone, E. Sánchez García, R. Santorelli, C. Seoane, J. Sosiak, S. Sulis, C. Tierney, S. Tullio, G. Vera Díaz

Instrumentation and Detectors

Kilopixel Performance of the Kinetic Inductance Detectors for the Terahertz Intensity Mapper

Justin S. Bracks, Reinier M. J. Janssen, Steve Hailey-Dunsheath et al. (+32 more)

We characterize a flight-grade array of lumped-element kinetic inductance detectors (LEKIDs) developed for the long-wavelength module of the Terahertz Intensity Mapper (TIM). From an 864-pixel science array, we select 490 well-isolated resonators spanning the focal plane and readout band and measure their thermal response, optical responsivity, and noise using a ZCU111-based multitone readout system intended for flight. The thermal and optical response of the detector population is consistent with previous single-pixel measurements and can be described by Mattis-Bardeen theory under the influence of a change in Cooper pair or quasi-particle density. Under increasing blackbody loading, the measured noise transitions from a thermal generation-recombination-dominated floor to photon-noise-limited scaling, with the majority of detectors achieving photon-noise-limited operation by approximately 400 fW incident power, with a median detector noise-limited NEP of $NEP_{det} = 1.1\times10^{-17} W \sqrt{Hz}$. The measured photon-noise scaling implies a median optical efficiency of approximately 0.67, indicating additional unknown loss sources between the detectors and blackbody radiator, tentatively attributed to losses in the waveguide. These results demonstrate that the TIM LEKID architecture retains the required sensitivity when scaled to kilopixel-class arrays; the principal remaining challenges are array-level tone optimization, resonator tracking, and identification of frequency-domain collisions.
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All authors Justin S. Bracks, Reinier M. J. Janssen, Steve Hailey-Dunsheath, Talia Saeid, Bruce Bumble, Logan Foote, Elijah Kane, Lun-Jun Liu, Charles M. Bradford, Shubh Agrawal, James E. Aguirre, Hrushi Athreya, Brockton S. Brendal, Karia Dibert, Peter Dow, Jeffrey P. Filippini, Jianyang Fu, Karolina G. Garcia, Christopher E. Groppi, Bradley Johnson, Dylan Joralmon, Wooseok Kang, Garrett K. Keating, Ryan P. Keenan, Ian N. Lowe, Alex Manduca, Aashrita Mangu, Daniel P. Marrone, Philip D. Mauskopf, Evan C. Mayer, Sydnee ODonnell, Simon Tartakovsky, Mathilde Van Cuyck, Joaquin D. Vieira, Jessica A. Zebrowski

Tuesday 29 September

Instrumentation and Detectors · Cross-listed from quant-ph

Towards noble gas quantum optical magnetometry using direct ultraviolet detection

James Maldaner and Gil Porat

We analyze a novel approach for quantum magnetic sensing via optical detection of nuclear spin precession in a noble gas. The detection is carried out with an ultraviolet frequency comb laser, so no alkali vapor is required to be mixed with the noble gas during the sensing stage, allowing for hours-long spin relaxation time at room temperature. Our analysis reveals that combining high laser power and low laser intensity noise is crucial to achieving and exceeding state-of-the-art magnetometric performance, including that of cryogenic magnetometers. We find operational regimes where either fundamental or technical noise dominate, which directs experimental effort towards increasing laser power or lowering laser intensity noise, respectively. We also show that optimizing beam size is key to achieving optimal sensitivity. Our calculations predict that a record-breaking sensitivity of $24~\mathrm{aT}/\sqrt{\mathrm{Hz}}$ is achievable in 10 minutes with a 10 W ultraviolet laser with a relative intensity noise of -100 dBc/Hz.
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Instrumentation and Detectors · Cross-listed from physics.optics

Nonreciprocal Polychromatic Radiation from a Space-Time-Modulated Omega-Topology Meta-Transceiver

Sajjad Taravati and Ya-Adama Kabia

Time-modulated metasurfaces offer a magnet-free route to nonreciprocal wave control, but existing realizations modulate only the electric response of the structure, and proposals for simultaneous electric-magnetic modulation have so far remained theoretical. We experimentally demonstrate a space-time-periodic meta-transceiver whose omega-topology unit cell integrates varactor-loaded electric (dipole) and magnetic (ring) resonators, both modulated by a common unidirectional traveling-wave bias. This modulation gives rise to two independent, experimentally resolved manifestations of nonreciprocity: on transmit, the incident field is efficiently converted into a polychromatic comb of harmonics that radiate at distinct, bias-reconfigurable angles, while on receive, the same modulation instead suppresses frequency conversion and routes the incoming wave preferentially toward one port over the other. These two effects - nonreciprocal polychromatic conversion and unidirectional wave routing - arise from a single unidirectional space-time modulation but act on distinct physical observables, frequency content and spatial direction, respectively. Measured near the electric resonance with a shared bias, these effects characterize the complete cell and do not separate its electric and magnetic contributions. Our results establish the space-time-modulated omega-topology cell as an experimentally viable platform for reconfigurable, full-duplex nonreciprocal wave transformation.
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Instrumentation and Detectors · Cross-listed from physics.optics

Multimode radiation pressure actuation of a mechanical resonator using a spatial mode sorter

Morgan E. Choi, Daniel Allepuz-Requena, Diego Torres-Barajas et al. (+2 more)

Multimode optomechanical scattering is ubiquitous in free-space imaging protocols, but its radiation pressure counterpart is challenging to detect with extended objects. Here we demonstrate radiation pressure actuation of a nanomechanical membrane using dynamically structured light from a spatial mode demultiplexer (SPADE). Using single- and two-mode illumination, we directly image the position-dependent intermodal coupling between Hermite-Gauss (HG) modes as mediated by the membrane's motion. As an application, we use multimode radiation pressure feedback to simultaneously cool two nearly degenerate membrane modes. Our results are applicable to diverse mechanical systems and serve as a stepping stone to SPADE-based quantum optomechanics.
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All authors Morgan E. Choi, Daniel Allepuz-Requena, Diego Torres-Barajas, Neshat Sadafi, Dalziel J. Wilson

Instrumentation and Detectors · Cross-listed from hep-ph

Endothermic Dark Matter at LZ from a Decaying Parent

Yongsoo Jho, Sanghwan Kim and Seong Chan Park

The LUX-ZEPLIN experiment has reported a nuclear-recoil candidate near 248 keV. We investigate a decay source for an endothermic interpretation: a long-lived dark parent produces energetic ground-state particles that upscatter on xenon. The parent mass fixes the injection energy, while its lifetime determines the absolute flux through the Galactic dark-matter column density. We include the Doppler broadening from parent and observer motion and use exact scattering kinematics with natural xenon isotopes. For a scalar contact interaction, a benchmark with a 10 MeV incident state and a 506 MeV parent gives an efficiency-weighted recoil spectrum peaked at 248.5 keV. One event in a specified high-energy window requires $\tau_X \simeq 4.4 \times 10^{20}$ s $f_X [\sigma_{\text{ref}}/(10^{-36} \text{cm}^2)]$, with a normalization sensitive to the nuclear response. We quantify the accompanying elastic-scattering requirement and the target-dependent thresholds. The calculation identifies a decay realization of the boosted flux and the portal conditions needed to preserve the recoil signal; a detector-level fit and ultraviolet-specific constraints remain necessary for a complete experimental assessment.
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Instrumentation and Detectors

Quantitative Interleaved-Pulse Acquisition Extends the Range of Isotope-Ratio Measurements in ToF-SIMS

Anton V. Ievlev

Isotope ratios underpin tracer studies of transport in oxides, battery materials, and biological systems, yet time-of-flight secondary ion mass spectrometry (ToF-SIMS) struggles to quantify ratios whose members differ in intensity by orders of magnitude: a primary-ion pulse long enough to count the minor isotope precisely can saturate the major isotope, whereas a pulse short enough to keep the major isotope linear yields too few minor-isotope counts. We show that multi-pulse-width acquisition yields quantitative isotope ratios when a dose factor measured within each crater links the phases and each isotope is taken only from phases in which it remains linear; we call this quantitative reconstruction interleaved-pulse acquisition. Pulse widths are selected from measured transfer curves and peak shapes. On thermal SiO2, a tuned (6, 35) ns pair achieves the same per-layer precision as short-pulse acquisition with a 13-fold reduction in the number of analysis frames. On 18O-enriched WOx films, interleaving extends the quantifiable range at the low-fraction end by about 14-fold. Across isotope ratios spanning approximately 1:500 to 1:1, the interleaved reconstruction agrees with the corresponding linear reference measurements, showing no measurable bias introduced by interleaving, and natural-abundance ratios of oxygen, strontium and titanium are reproduced within several percent. The method requires no hardware additions and enables depth-resolved isotope-ratio measurements over a wide range within a single crater.
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Instrumentation and Detectors · Cross-listed from physics.optics

Scanless quantum Fourier-transform mid-infrared spectroscopy for solids and surface analysis

Paul Gattinger, Michela Conti, Franziska Dietz et al. (+4 more)

Quantum infrared (IR) spectroscopy is a novel technique based on nonlinear interferometry and quantum sensing with undetected photons. In this approach, spectrally far-separated correlated photon pairs are used for detection and probing, respectively. Hence, the probing wavelength domain (mid-IR) is substantially different from the detection spectral range (near-IR), which enables shot-noise-limited and cost-effective sensing schemes attractive for applied metrology. In this paper, we implement and employ a custom-built scanless quantum Fourier-transform mid-IR (sQFTIR) microspectrometer for chemical characterization and analysis of solids and interfaces. The sQFTIR system employs spectral-domain acquisition, without the need to scan the optical delay. This results in enhanced sensitivity and short measurement times and therefore enables rapid spectral acquisitions in 100~ms spanning a spectral band from 3000 cm$^{-1}$ - 2400 cm$^{-1}$. The capabilities of our approach are demonstrated for hyperspectral mid-IR imaging of dried pharmaceuticals (insulin on a gold surface) and investigation of a security feature on a banknote. Furthermore, we demonstrate hyperspectral imaging and spectroscopy through a turbid ceramic medium.
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All authors Paul Gattinger, Michela Conti, Franziska Dietz, Andrei N. Halangescu Moldovan, Andreas W. Schell, Markus Brandstetter, Ivan Zorin

Instrumentation and Detectors · Cross-listed from hep-ex

Trace isotopes set the neutron horizon of liquid argon

Yasser Maghrbi

Near 57 keV, destructive interference makes argon-40 almost transparent to neutrons. The 0.4% of argon-36 and argon-38 in natural argon then supply over 90% of its opacity, amplified 230-fold. Published transmission data rule out the argon-36 evaluation FLUKA uses by default, even with every other isotope made transparent, and bound its cross section in the window to 2-11 b. In a DUNE-scale detector, switching to the data-consistent evaluations moves the fiducial fraction of argon-41 calibration captures by 9-13% while the total yield changes by only 2%: the effect is on where captures occur, not how many.
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Instrumentation and Detectors

Development and Performance Study of a Capillary Liquid Scintillator Neutron Detector

Guang Luo, Jian Yu, Dikai Li et al. (+9 more)

Capillary liquid scintillator detectors are promising for high-resolution neutron imaging, yet experimental data on their light spread mechanism and spatial performance remain limited. Here, we report a neutron detector based on a hexagonal capillary array filled with EJ-309 liquid scintillator, with an inner diameter of about 50 um and a camera readout of 9 um pixels. Laser experiments show that the FWHM of the full light spot decreases from 260 um to 90 um with a metal light absorber, confirming effective suppression of lateral light spread. Using an AmBe neutron source, an effective field of view with a 5-sigma threshold was established from background frames. For single-capillary events, the pulse height spectrum follows a Landau distribution with a most probable value of 0.133 +/- 0.001 (stat.), and the intrinsic detection efficiency is 10.07% +/- 1.26% (stat.) +/- 1.43% (syst.), corresponding to about 13.55% when normalized to the active liquid scintillator area. The point spread function core yields a radial FWHM of 12.8 um and a centroid positioning precision of approximately 5.5 um (1 sigma), while the intrinsic position resolution is limited by the capillary pitch to 54 um. Linearity is good for 1 to 2 capillaries, with deviation appearing for 2 to 3 capillaries due to additional capture of spread light. These results provide experimental basis and physical understanding for imaging applications of capillary liquid scintillator neutron detectors.
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All authors Guang Luo, Jian Yu, Dikai Li, Yanmeng Dai, Meiling Chen, Jiaqiang Zou, Ke Yan, Shaoxuan Cui, Ge Jin, Zhao Xu, Chunhui Zhang, Leifeng Cao

Monday 28 September

Instrumentation and Detectors

A portable neutron scatter camera with isotropic sensitivity

S. G. Yoon, L. Larizgoitia, C. M. Lewis et al. (+2 more)

We describe the design and characterization of a neutron scatter camera specifically developed for the study of neutron fields (flux, energy, direction) in experimental areas of spallation facilities, where multiple neutron sources can simultaneously contribute. A combination of hardware and logic triggers provides the isotropic response required for this application. Neutron source locations are accurately reconstructed on images from a built-in 360$^\circ$ panoramic camera. The full understanding of neutron fields that the device provides can be used for site selection and abatement of neutron backgrounds affecting sensitive instruments such as coherent elastic neutrino-nucleus scattering (CE$\nu$NS) detectors to be located at the upcoming European Spallation Source.
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All authors S. G. Yoon, L. Larizgoitia, C. M. Lewis, F. Monrabal, J. I. Collar

Instrumentation and Detectors · Cross-listed from physics.optics

Low-loss amorphous dielectric metasurface mirror for precision optical cavities

Swadha Pandey, Peter Fritschel and Matthew Evans

We report the design and experimental realization of a low-loss dielectric metasurface mirror operating at 1064 nm, the primary wavelength of interferometric gravitational-wave detectors. The mirror consists of a single layer of titanium dioxide nanopillars on a glass substrate, achieving high reflectivity via guided-mode resonance. The fabricated mirror has a peak reflectance of 99.10% with a total optical loss of 0.26%, representing, to our knowledge, the highest reflectance and lowest optical loss experimentally demonstrated in a substrate-supported purely amorphous dielectric metasurface mirror operating in the visible to near-infrared. This single-layer metasurface is projected to reduce coating Brownian noise by a factor of 3-5 relative to conventional dielectric Bragg mirrors at comparable reflectivity, which would improve the performance of precision optical cavities currently limited by this noise. These results indicate the potential of dielectric metasurfaces as a platform for next-generation precision measurement systems.
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Instrumentation and Detectors

Non-Ionizing Radiation Measurements for Trajectography Radars

J. Marcos Leal Barbosa Filho, Millena M. de M. Campos, Daniel L. Flor et al. (+4 more)

This work presents a Non-Ionizing Radiation (NIR) measurement campaign and proposes a specific measurement method for trajectography radars. This kind of radar has a high gain narrow beam antenna and emits a high power signal. Power density measurements from a C-band trajectography radar are carried out using bench equipment and a directional receiving antenna, instead of the commonly used isotropic probe. The measured power density levels are assessed for compliance test via comparison with the occupational and general public exposure limit levels of both the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Brazilian National Telecommunication Agency (Anatel). The limit for the occupational public is respected everywhere, evidencing the safe operation of the studied radar. However, the limit for the general public is exceeded at a point next to the radar's antenna, showing that preventive measures are needed.
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All authors J. Marcos Leal Barbosa Filho, Millena M. de M. Campos, Daniel L. Flor, William S. Alves, Adaildo G. D'Assunção, Marcio E. C. Rodrigues, Vicente A. de Sousa Jr

Instrumentation and Detectors

Design and Analysis of a 2D Vernier Structure

Hüsna Yildiz and Rick Helmer

This paper presents the design and simulation of a 2D Vernier Time-to-Digital Converter (TDC) targeting less than 20 picosecond time resolution and 5-bit output resolution. The TDC comprises voltage-controlled delay buffers, NAND-based SR latches with reset functionality, and a calibration loop using a phase-frequency detector (PFD) and charge pump. The calibration loop dynamically adjusts delay mismatches to maintain consistent timing across process-voltage-temperature (PVT) corners, significantly improving linearity. Simulations show that the TDC achieves a resolution of 16.9 ps for tt corner and maintains DNL and INL below 0.5 LSB under all tested PVT conditions
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Instrumentation and Detectors

Electrothermal behavior of superconducting nanowires buried in a commercial CMOS process

Mohamed Gharib, Leonid Popryho, Salma Abdelzaher et al. (+14 more)

Superconducting films native to a commercial CMOS process enable co-integration of superconducting devices (high-kinetic-inductance elements and nanowire detectors) with cryogenic CMOS on one monolithic die. Such films are buried in the front-end-of-line, beneath the back-end-of-line metal stack, an environment that might quench a self-heated hot spot. Current-voltage characteristics are reported for titanium nitride (TiN) nanowires in the polycrystalline-silicon resistor layer of a 22 nm FD-SOI process, and measured retrapping currents are compared with thermal models for longitudinal conduction to the contacts and interfacial phonon cooling into the stack. The wires are strongly hysteretic, with switching-to-retrapping current ratios I_sw/I_r of 7.4-9.8, sustaining a normal hot spot. For two wires of length ell = 50 micrometers and widths W = 0.50 and 1.00 micrometers, over bath temperatures T_b = 0.15-1.19 K, I_r follows the interfacial form (T_hs^n - T_b^n)^(1/2) with n = 4 (T_hs, the effective hot-spot temperature), and is strongly inconsistent with the (T_hs - T_b)^(1/2) constant-kappa longitudinal-conduction limit; free-exponent fits give n = approximately 4.8-5.0. An effective cooling coefficient Sigma_K = 7.9(3) W/(m^2 K^4) describes the data: 31(21) times below the acoustic- (diffuse-) mismatch value for a single clean interface, and approximately 12 times below the lowest previously reported comparable nanowire coefficient. The model-based film thermal conductivity is kappa = approximately 20 mW/(m K). Across lengths ell = 1-50 micrometers, I_r matches neither ell^(-1) of pure longitudinal conduction nor ell^0 of pure interfacial cooling; a two-channel model reproduces I_r(ell) with crossover length ell* = approximately 3.5 micrometers predicted, to an O(1) prefactor, from Sigma_K and kappa.
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All authors Mohamed Gharib, Leonid Popryho, Salma Abdelzaher, Tejas Guruswamy, Tomas Polakovic, Umeshkumar Patel, Orlando Quaranta, Thomas Cecil, Clarence Chang, Yu-Sheng Chen, Thomas H. Swift, Grayson M. Noah, Alberto Gomez-Saiz, John J. L. Morton, M. Fernando Gonzalez-Zalba, Antonino Miceli, Inna Partin-Vaisband

Instrumentation and Detectors

A high-flux electron detection system to measure non-linear Compton scattering at LUXE

Antonios Athanassiadis, Oleksandr Borysov, Florian Burkart et al. (+16 more)

This paper presents the development and testing of a high-flux electron detection system designed to measure the energy spectrum of more than $10^9$ electrons from laser-electron collisions at the LUXE experiment, planned at DESY. The system is intended to enable precision measurements of non-linear Compton scattering in the strong-field regime of quantum electrodynamics. It combines a scintillating screen observed by a camera system with a spatially segmented detector based on the Cherenkov effect. Prototype tests were conducted at two accelerator facilities, where the performance of the system was evaluated under realistic beam conditions. The results demonstrate the feasibility of the detector concept, characterize its current performance and limitations, and provide input for the optimization and final design of the detection system to be used in the experiment.
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All authors Antonios Athanassiadis, Oleksandr Borysov, Florian Burkart, Hannes Dinter-Habermeier, John Hallford, Beate Heinemann, Louis Helary, Luke Hendriks, Ruth Jacobs, Max Kellermeier, Willi Kuropka, Jenny List, Frank Mayet, Gudrid Moortgat-Pick, Evan Ranken, Stefan Schmitt, Ivo Schulthess, Thomas Vinatier, Matthew Wing

Instrumentation and Detectors

Event-by-event track imaging of charged particles with an ultrafast plenoptic camera

Till Dieminger, Marco Barbieri, Vincenzo Berardi et al. (+8 more)

Modern elementary particle detectors often require high-resolution three-dimensional particle tracking in large dense active volumes, which is difficult to achieve in standard devices without an extremely fine segmentation. In recent work, a plenoptic camera instrumented with a single-photon avalanche-diode array, called PLATON, demonstrated to image individual visible photons generated in monolithic scintillating material and reconstruct their three-dimensional origin from a single-event exposure, opening a route to high-spatial-resolution detection of elementary particles in unsegmented scintillator. However, those tests aimed to address photon sources of essentially zero geometric extent. In this work we close the gap to the tracking regime. First, we calibrated the PLATON prototype using light tracks in an organic plastic scintillator induced by a femtosecond infrared laser via two-photon absorption and characterised its capability to reconstruct photon-starved 3D lines with a novel algorithm, achieving good agreement with custom Monte Carlo simulation. Finally, the PLATON prototype was exposed to a test beam of pions at the CERN Proton Synchrotron. For the first time, a plenoptic detector system was successfully used to detect and reconstruct the 3D tracks of elementary particles from 2D photon-starved images on an event-by-event basis marking a transformative approach to high-resolution measurements.
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All authors Till Dieminger, Marco Barbieri, Vincenzo Berardi, Saúl Alonso-Monsalve, Kodai Kaneyasu, Paul Mos, Tim Weber, Johannes Wüthrich, Claudio Bruschini, Edoardo Charbon, Davide Sgalaberna