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Physics Physics Instrumentation and Detectors

physics.ins-det Watch Instrumentation and Detectors

Wednesday 16 September

Instrumentation and Detectors

Terahertz Radar Inversion for Range-Resolved Solids Concentration Profiling in Gas–Solid Flows

Philip Kjaer Jepsen, Albert Monteith, Diana Carolina Guío-Pérez et al. (+4 more)

A stable inversion method is developed to reconstruct millimeter-scale solids-concentration profiles in particulate suspensions from monostatic sub-terahertz frequency-modulated continuous-wave (FMCW) radar measurements. In industrial particulate flows, cumulative attenuation renders the direct inversion of the path-integrated volume-scattering radar equation ill-conditioned. The method resolves this by an ensemble-averaged Mie-scattering closure coupled to a stable backward-integration scheme, yielding an analytical solution for the range-resolved solids concentration without case-specific parameter fitting against reference concentration measurements. The required range-dependent system response is determined by absolute near- and far-field calibration via external substitution with an electrically large metallic sphere. The method was evaluated against solids-volume-fraction estimates derived from differential-pressure measurements in a 3.1 m-tall circulating fluidized-bed riser operated with ambient air and copper powder (median diameter 32.6 $\mu$m, density 8920 kg m$^{-3}$). The radar-derived and pressure-derived profiles agreed well across three superficial gas velocities producing distinct axial solids distributions, and the radar indicates sensitivity down to solids volume fractions of order $10^{-6}$.
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All authors Philip Kjaer Jepsen, Albert Monteith, Diana Carolina Guío-Pérez, Lars Ulander, Tomas Bryllert, Henrik Ström, David Pallarès

Instrumentation and Detectors

On the importance of cosmic-ray background in the Atomki anomaly

Hicham Benmansour, Gianluigi Boca, Gianluca Cavoto et al. (+8 more)

We report Geant4-based simulations of cosmic-ray muon backgrounds in models reproducing the geometries of the five-arm and six-arm e+e- pair spectrometers operated by the Atomki group at Debrecen. Full detector geometries are implemented for both setups, including position-sensitive detectors and plastic scintillators. In both configurations, cosmic muons generating two-arm coincidences produce statistically significant excesses in the opening-angle distribution whose positions are determined by the discrete azimuthal arrangement of detector arms and the plastic scintillators dimensions: in the six-arm spectrometer a peak appears near 140 degrees when the scintillator energy sum is selected in the 8Be transition window (16-20 MeV) and is suppressed for energy-asymmetric pairs, while a distinct peak near 120 degrees emerges in the 4He window (18-22 MeV), with no comparable enhancement in the respective background energy region. These angles, asymmetry dependences, and background characteristics show behaviours similar to those reported by the Atomki group as evidence for a 17 MeV boson. For the five-arm setup, a 140-degree excess is also reproduced at 8Be energies, and normalizing internal pair conversion events and cosmic coincidences to typical Atomki running conditions yields a cosmic-to-IPC ratio above unity in the signal window, indicating that the cosmic background is a leading contribution to the event rate at the energies and angles of interest. While they do not settle the question of the origin of the Atomki excesses, these results highlight the critical importance of a robust cosmic-ray treatment in this type of measurements, and call for a detailed description of the beam-off studies supporting the search for anomalies in the opening-angle vs. energy-sum distribution around the signal region.
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All authors Hicham Benmansour, Gianluigi Boca, Gianluca Cavoto, Marco Chiappini, Elia G. Grandoni, Luca Galli, Giovanni Gallucci, Angela Papa, Francesco Renga, Antoine Venturini, Cecilia Voena

Instrumentation and Detectors · Cross-listed from physics.optics

Multi-contrast wide-field mid-infrared photothermal imaging

Anooj Thayyil Raveendran, Cornelia Reuter, Samir F. El-Mashtoly et al. (+2 more)

Wide-field mid-infrared photothermal (MIP) imaging enables high-speed, chemically specific imaging at sub-micrometer spatial resolution through several possible contrast mechanisms, including scattering change, fluorescence modulation, and phase change. Each mechanism offers distinct advantages, yet existing wide-field MIP instruments have typically been limited to a single contrast mechanism so far, requiring a dedicated instrument for each. Here, we introduce a switchable multi-contrast wide-field MIP microscope that allows the photothermal readout mechanism (based on scattering-, fluorescence-, or quantitative phase imaging (QPI)) to be matched to the sample and imaging conditions. We characterize the spectral fidelity and signal-to-noise (SNR) ratio of each mechanism using 5 \mu m polystyrene (PS) beads, and the effective spatial resolution using 300 nm PS beads. Scattering- and fluorescence-based detection achieved a sub-500 nm measured point spread function full width at half maximum, while QPI-based detection reached approximately 900 nm but provided up to 26-fold higher SNR than scattering. We further demonstrate imaging across a range of samples, including A549 cells in buffer, mouse lung tissue section, bacteria, and SU8 polymer at 1.4 and 5 \mu m thickness, with a field of view exceeding 200 \mu m. Comparison across these samples shows that each contrast mechanism offers distinct trade-offs in resolution, sensitivity, and applicability, guiding readout-strategy selection by sample type. These results establish a flexible, switchable multi-contrast platform for wide-field MIP imaging, with broad applicability across polymer and biological samples.
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All authors Anooj Thayyil Raveendran, Cornelia Reuter, Samir F. El-Mashtoly, Jürgen Popp, Christoph Kraft

Instrumentation and Detectors · Cross-listed from physics.optics

Environmental qualification and performance of a CubeSat-scale dual optical frequency comb payload for space applications

Stephanie D. Leifer, Matthew J. Kelley, Natalie Walsh et al. (+23 more)

We report the environmental qualification and performance of CombSat, a dual optical frequency comb payload designed for deployment on a 12U CubeSat in low Earth orbit. The payload integrates two self-referenced, 200 MHz hybrid fiber-waveguide frequency combs, a narrow-linewidth optical reference, a heterodyne beat detection unit, and FPGA-based control electronics in a total mass of 8.3 kg and volume of 5.7 L, and nominal power consumption of 21W. We describe the mechanical, thermal, and radiation-tolerant design features of the system and present the results of random vibration, storage temperature cycling, and thermal-vacuum testing conducted in accordance with NASA's General Environmental Verification Standard. We show that key comb performance metrics including oscillator and amplifier output power, frep, fCEO, and fopt signal-to-noise ratios, and integrated phase noise, remain within specification after environmental exposure, and we discuss observed failure modes and design modifications that improved robustness. These results demonstrate that compact, low power, fully stabilized, autonomous dual-comb systems can be engineered and qualified for spaceflight on CubeSat platforms, providing a path forward for future low-cost comb-based space applications.
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All authors Stephanie D. Leifer, Matthew J. Kelley, Natalie Walsh, Ziba Shahriary, Paul Steinvurzel, Chrissy Fortuna, Geoffrey Maul, Adam Darley, Ian Coddington, Laura C. Sinclair, Ariel Berman, Victor Chin, Henry Timmers, Kevin Knabe, Jason Pinon, Andrew Attar, Cole Smith, Cyrus Bry, Davis S. Kun, Stan Stanev, Nicole Thai, Bennett Sodergren, Daniel Deveraux, Grant Capan, Will McIntyre, Manas Choure

Tuesday 15 September

Instrumentation and Detectors

Automated Physics-Informed Neural-Networks-Based Calibration of Highly Segmented Silicon Telescopes

M. Rejmund, A. Lemasson, P. Morfouace et al. (+3 more)

Transfer and multi-nucleon transfer reactions are essential tools for probing nuclear structure and reaction dynamics, requiring precise determination of the identity, energy, and emission angles of reaction products. The increasing granularity of modern silicon telescope arrays enhances experimental capabilities but challenges detector calibration, as conventional channel-by-channel approaches become inefficient and difficult to scale. In this work, we present a fully automated, physics-informed calibration framework based on neural networks, specifically designed for highly segmented silicon detector arrays. The method formulates calibration as a global optimization problem, in which detector gains and geometrical corrections are determined simultaneously by minimizing the width of the reconstructed excitation energy under two-body kinematics constraints. The approach relies exclusively on experimental data and well-established physical principles, without requiring explicit modeling of detector response. A distinctive feature is the use of multiple neural network sub-models sharing a common loss function with embedded physics constraints, enabling coherent and self-consistent calibration across all detector channels. This strategy ensures scalability, robustness, and reproducibility, making it particularly suitable for next-generation detector systems with increasing complexity. The performance of the method is demonstrated using experimental data from the Particle-Identification Silicon-Telescope Array (PISTA) in high-resolution fission studies in inverse kinematics. The results show excellent agreement with theoretical kinematics, high-quality particle identification, and a significant improvement in calibration efficiency. The proposed framework provides a general and adaptable solution for the calibration of complex detector systems in modern nuclear physics experiments.
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All authors M. Rejmund, A. Lemasson, P. Morfouace, D. Ramos, J. Taieb, J. D. Frankland

Instrumentation and Detectors · Cross-listed from quant-ph

Efficiency-Resolved Recovery Dynamics of an Free-Running InGaAs/InP Single Photon Avalanche Detector Operated in Gated Mode

Bruno Santos Souza, Vitor Tavares, Filippo Ghiglieno et al. (+2 more)

Detection efficiency in gated-mode single-photon avalanche detectors recovers gradually after each gate edge, limiting attainable count rates, yet quantitative recovery models exist only for free-running operation. We extract the gated recovery time constant of a free-running InGaAs/InP detector at 1550 nm by sweeping the gate frequency from 100 kHz to 1 MHz and globally fitting count rates across four dead times, requiring neither a pulsed laser nor a time-to-digital converter. The recovery time decreases linearly with detection efficiency, from 301 to 161 ns between 10 % and 25 %, at 9.3 ns per percentage point. We further resolve a periodic count-rate modulation consistent with bias-dependent capacitive gate feedthrough.
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All authors Bruno Santos Souza, Vitor Tavares, Filippo Ghiglieno, Celso Jorge Villas-Boas, Paulo Henrique Dias Ferreira

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

Fast, optimal readout of a tethered optomechanical pressure sensor

Stephen R. Chen, Yiliang Bao, John R. Lawall et al. (+2 more)

We demonstrate a fast readout method for tethered optomechanical pressure sensors. The fast readout method allows mechanical ring-down measurement rates that exceed the total mechanical damping rate $\Gamma_t$. We model the uncertainty of our ring-down measurements with the Cramér-Rao bound, including the effect of thermomechanical noise. Both our data and the Cramér-Rao bound indicate that measurement rates on the order of the mechanical damping rate produce the lowest uncertainty. At low pressures, using the optimal measurement rate allows 10$\times$ faster measurements or 3$\times$ lower uncertainty compared to allowing our sensor to ring down to the thermomechanical noise floor. Our results allow tethered optomechanical pressure sensors to operate at rates comparable to commercially available pressure gauges, removing an obstacle to adoption of optomechanical pressure sensors in industrial settings.
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All authors Stephen R. Chen, Yiliang Bao, John R. Lawall, Jason J. Gorman, Daniel S. Barker

Instrumentation and Detectors · Cross-listed from astro-ph.IM

Characterization of IBEX LmAPD detectors at CEA for future low-noise NIR astronomy instruments

Jean Le Graët, Vincent Affatato, Marion Baumann et al. (+9 more)

Future near-infrared (NIR) astronomy missions dedicated to photon-starved science cases, in particular an all-sky astrometric survey extending the legacy of Gaia into the NIR, as identified within the ESA Voyage~2050 programme, require large-format detectors combining sub-electron effective read noise with very low dark current. Linear-mode avalanche photodiodes (LmAPDs) based on HgCdTe meet this need by multiplying the photo-generated charge by an avalanche gain before the readout stage, thereby reducing the relative contribution of the read noise. We report the first electro-optical characterization of an IBEX detector, a $2048\times2048$, \SI{15}{\micro\meter}-pitch HgCdTe LmAPD array developed by Leonardo with the European Space Agency and operated at \SI{80}{\kelvin} on a dedicated bench at CEA-IRFU. We first discuss the central difficulty of characterizing an APD array, the degeneracy between avalanche gain, quantum efficiency (QE), and conversion gain in the measured response, and we then separate the measurements into two categories. Among the quantities that are directly measurable without assumptions, we report a signal-to-noise ratio for a CDS measurement that exceeds that of a Euclid-type H2RG above \SI{8}{\volt} pixel bias under identical low-flux conditions, a photo-response non-uniformity stable at the $\sim$10% level, and a quantum efficiency-to-excess-noise ratio (QEFR) of \num{0.40} at \SI{10.5}{\volt}. Among the quantities derived under an explicit set of assumptions, we obtain a conversion gain corresponding to a sense-node capacitance of \SI{27}{\femto\farad}, a quantum efficiency of $46\pm12\%$ at \SI{2.5}{\volt}, and an excess noise factor $F=1.15\pm0.14$ at \SI{10.5}{\volt}. These results establish IBEX as a promising European large-format detector for future ultra-low-flux NIR instruments.
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All authors Jean Le Graët, Vincent Affatato, Marion Baumann, Olivier Boulade, Cyrille Delisle, Eloy Hernandez, Christian Ketchazo, Frederic Lemmel, Vincent Moreau, Salima Mouzali, Thibault Pichon, François Visticot

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

A transfer-rod-mounted rotatable sample holder enabling a compact modular vacuum system for ion-beam milling, oblique magnetron sputtering, and co-sputtering

Tiago de Oliveira Schneider, Folke Kaiser, Andreas Semrad et al. (+2 more)

We present a novel multifunctional sample-holder concept for compact research-scale vacuum systems. The sample holder is mounted directly on the transfer rod and remains mechanically connected to it throughout loading, transfer, deposition, and ion-beam milling. In contrast to conventional layouts, no handover to a separate substrate stage is required. By combining axial transfer motion, rotation around the transfer-rod axis, and independent substrate rotation, the holder itself defines the relevant process geometries and enables standard deposition, oblique deposition at freely selectable incidence angles, substrate rotation, and co-sputtering from adjacent sources. A shielding plate integrated into the sample holder acts as both a substrate shutter and a source shield. This reduces the need for separate shutter mechanisms and allows a compact radial arrangement of four 2-inch magnetron sputter sources without source-tilting mechanisms. The concept was implemented in a modular vacuum system assembled from standard DN100CF components, combining a load lock, magnetron sputtering, and ion-beam milling. The system reaches a base pressure of $5 \cdot 10^{-8}\,\mathrm{mbar}$ without bakeout. The functionality of the sample-holder concept is validated by oblique deposition of Ta/CoFeB bilayers, which exhibit pronounced uniaxial in-plane magnetic anisotropy, and by co-sputtering of an Au–Ag composition series, whose resistivity follows the expected Nordheim-type composition dependence.
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All authors Tiago de Oliveira Schneider, Folke Kaiser, Andreas Semrad, Peter Kießlich, Markus Meinert

Instrumentation and Detectors

Design and Simulation Study of the Hadronic Calorimeter for the EicC Zero Degree Calorimeter

Maiyu Wang, Yuan Li, Hao Wang et al. (+6 more)

The Zero-Degree Calorimeter (ZDC) at the proposed Electron-Ion Collider in China (EicC) is essential for detecting forward-going neutral particles and supporting the core nucleon spin and 3D imaging physics programs. In this work, a highly compact Spaghetti Calorimeter (SPACAL) architecture is proposed and optimized as the baseline design for the ZDC hadronic section. To systematically and quantitatively evaluate its physics capabilities, a comprehensive end-to-end Geant4 simulation framework was developed, integrating energy deposition, optical photon transport, photo-detection, and modeled front-end signal digitization. The optimized detector demonstrates excellent performance for neutron detection, achieving an energy resolution of $33.42\%/\sqrt{E/\mathrm{GeV}} + 1.47\%$ and a timing resolution of approximately 500 ps, outperforming the targeted specification. Furthermore, full-system simulations incorporating the upstream electromagnetic calorimeter yield a sub-centimeter transverse position resolution. Moreover, topological shower shape analysis across the full detector system provides robust particle identification (PID), with photon-neutron separation accuracy reaching over $99\%$ for high-energy incident particles. These quantitative results confirm that the SPACAL design fully satisfies the stringent operational and physics requirements of the EicC forward kinematic region.
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All authors Maiyu Wang, Yuan Li, Hao Wang, Xikun Sun, Zixiang Zhou, Yutie Liang, Weizhi Xiong, Ye Tian, Ting Lin

Instrumentation and Detectors

Synchronization of PLC Subsystems with the Timing Distribution System at the European XFEL

Dmytro Levit, Bruno Fernandes, Peter Zalden et al. (+3 more)

The European XFEL generates bursts of up to 4096 ultra-short X-ray flashes with a spacing of only 222 ns every 100 ms. These flashes are produced in the linear electron acceler- ator by undulators and guided 1 kilometer in vacuum pipes until they reach the scientific experiments. Accurate synchronization and the availability of information about all configurable pulses within a single burst, which can vary every 10 Hz cycle, enable the full potential of control, monitoring, and measurement in terms of accuracy and utilization. The MicroTCA-based timing system provides all the necessary capabilities. However, the industrial programmable logic controllers (PLCs), which manage most of the control electronics of the beamlines and experiments, are only synchronized on a millisecond-level through UART and NTP interfaces. This paper presents a new development based on an FPGA SoC EtherCAT solution in MicroTCA that implements an interface to the PLC using distributed clocks to achieve synchronization on nanosecond-level and provide beam-related information in a deterministic manner.
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All authors Dmytro Levit, Bruno Fernandes, Peter Zalden, Tobias Freyermuth, Navid Mashayekh, Patrick Gessler

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

SpectraFit XPS: a free, browser-based application for X-ray photoelectron spectroscopy peak fitting and quantification

Yongsup Park

SpectraFit XPS is a free web application for the analysis of X-ray photoelectron spectroscopy (XPS) data that runs entirely in the browser, with no installation and no server-side processing: spectra never leave the user's computer. It combines an interactive Levenberg–Marquardt fitting engine with true Voigt, Doniach–Šunjić, and summed Gaussian–Lorentzian line shapes; Shirley (static and dynamic), linear, and Tougaard (two- and four-parameter) backgrounds; spin–orbit doublet generation; and expression-based inter-peak constraints. Quantitative analysis supports ten relative-sensitivity-factor sets, several kinetic-energy correction schemes including TPP-2M inelastic mean free paths, angular correction, and atomic and weight percentages, with the underlying database and algorithms adapted from the open-source KherveFitting project. The application reads and writes ISO~14976 (VAMAS) files—including multi-region and depth-profile data and load-time transmission-function correction—and imports common vendor and spreadsheet formats. A publication plotter exports journal-ready SVG/PNG figures. The quantification pipeline reproduces KherveFitting reference values exactly in a 30-case regression suite, part of an automated test set of 100 tests. The application, an illustrated bilingual user guide, and a synthetic demonstration dataset are freely available at https://spectrafit-xps.web.app/.
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Instrumentation and Detectors

Cyclotron-Frequency Stability via Single-Ion Fluorescence in a Penning Trap with a Cryogen-Free Superconducting Magnet

Anna Schupeta, David Yousaf, Manuel Almagro et al. (+6 more)

In this work, we investigate the magnetic-field stability of a Penning trap operated with a cryogen-free superconducting magnet through cyclotron-frequency measurements of a single laser-cooled calcium ion using two complementary photon-based detection techniques: a pulsed optical method for determining the three ion eigenfrequencies and Fluorescence-Detected Fourier-Transform Ion-Cyclotron-Resonance (FD-FT-ICR). For the former technique, the data-analysis procedure was revisited, considering it as the dominant contribution to the measurement uncertainty and yielding a long-term magnetic-field drift $(1/B)(dB/dt) = -3.07(32)\times10^{-9}$ $\mathrm{h}^{-1}$. This value is comparable to those reported for high-precision Penning-trap experiments employing liquid-helium-based superconducting magnets. The short-term stability was investigated using the FD-FT-ICR technique, resulting in a minimum relative magnetic-field variation of $\delta B/B \simeq 5\times10^{-8}$ for averaging times between 30 and 60 s. Furthermore, this technique enables direct cyclotron-frequency determinations on timescales as short as a few seconds, providing access to magnetic-field fluctuations that are generally not resolved in conventional Penning-trap experiments.
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All authors Anna Schupeta, David Yousaf, Manuel Almagro, Manuel Hurtado, José M. Palomino, Joaquín Berrocal, Michael Block, Christoph E. Düllmann, Daniel Rodríguez

Monday 14 September

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

Simulation study of accelerator-based muography using the GeV-scale forward muon component at SHINE

Jiangtao Wang, Yinghe Wang, Si Chen et al. (+7 more)

Muography exploits the penetrating power of muons to image the interior of large dense objects, but cosmic-ray sources provide only ~1 {cm}^{-2} {min}^{-1} predominantly from above, limiting imaging speed and accessible geometries. Electron-driven muon production has recently been demonstrated with laser-wakefield accelerators, but shot-to-shot fluctuations hinder systematic studies required for quantitative accelerator muography. Using Geant4 Monte Carlo simulations, we model the full experimental setup at Shaft 2 of the Shanghai High repetition rate XFEL and Extreme light facility (SHINE), from a 3 GeV, 50 pC, 50 Hz commissioning electron beam interacting with a muon target through 25 m of beamline structures and a 3 m-thick concrete isolation wall. Approximately 0.28 effective reconstructed single-muon events per bunch, with residual kinetic energies below 1.2 GeV after traversing the wall, reach the downstream muography test area (~14 s^{-1}). The wall absorbs most charged background particles below ~1 GeV, while residual neutrons can be discriminated by their characteristic detector energy deposition. Scattering-tomography simulations show that $3\times 10^{5}$ effective muon events, accumulated in approximately 6 h at the commissioning rate, yield a Structural Similarity Index above 0.9, demonstrating the feasibility of quantitative accelerator-based muography using SHINE's electron-driven GeV-scale forward muon source. At the 8 GeV/50 kHz benchmark, the projected muon intensity exceeds $5 \times 10^{4}$ {\mu}/s, corresponding conservatively to approximately one muon per bunch at the detector. This exceeds the cosmic-ray flux by orders of magnitude, while SHINE's superconducting linac provides a stable, controlled platform for developing electron-on-target muography.
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All authors Jiangtao Wang, Yinghe Wang, Si Chen, Rongbing Deng, Kim Siang Khaw, Jun Kai Ng, Qisheng Tang, Dong Wang, Wenzhen Xu, Jia Cheng Yap

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

Quantitative control and recording of materials-synthesis processes using an automated experimentation platform

Yusuke Hashimoto, Takaya Muramoto, Hikari Terada et al. (+3 more)

Data-driven materials development requires the collection of large amounts of high-quality materials data. Full autonomy of materials experiments is anticipated, but its technical hurdles are high and its adoption remains limited. In this study, we constructed a simple, easy-to-deploy automated experimentation platform that focuses not on full autonomy but on the reliable automation and quantitative recording of experimental processes. Specifically, commercially available instruments such as robot arms, electric pipettes, web cameras, and an electronic balance are combined, components such as fixtures are fabricated with a 3D printer, and the instruments are operated by control code generated by an AI agent based on a large language model. As a demonstration, we applied the platform to a two-solution mixing experimental system and synthesized ZIF-8, a metal-organic framework. A white suspension phase was observed in the product, and X-ray diffraction measurements confirmed that it was ZIF-8. We also found that its particle size distribution depends strongly on the solution dispensing speed of the electric pipette, which is a parameter that is difficult to control or record in manual operation. This dependence was reproduced in repeated runs, confirming the repeatability of the automated synthesis. This result is a good example showing that the control and recording of process parameters that are rarely quantified in manual work can govern the quality of materials data. All control code, CAD models, and documentation are made publicly available to encourage the spread of laboratory-scale automation of experiments.
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All authors Yusuke Hashimoto, Takaya Muramoto, Hikari Terada, Harim Song, Yuan Wang, Takaaki Tomai

Sunday 13 September

Instrumentation and Detectors

A rotation-based Hall-probe magnetic compass

B. Wojtsekhowski, C. Cuevas, R. Dawson et al. (+4 more)

In many physics and space experiments the direction of a magnetic field must be known to one milliradian or better. We have developed a new type of magnetic compass, based on rotation, in which a spinning Hall probe (HP) produces an alternating signal proportional to the component of the magnetic field transverse to the axis of rotation. Aligning the rotation axis so that this signal vanishes gives the direction of the field. The device requires no calibration and is insensitive to electronics drift. A spinning-HP compass was built and used in a recent experiment at Jefferson Lab, where it determined the direction of the 25~G holding field of a polarized $^3$He target to about 1~mrad; the direction of the rotation axis was transferred to the laboratory frame with a laser and a flat mirror attached to the rotor. A second implementation of the rotation approach, a spinning field concentrator (SFC) with a stationary Hall probe, was also built. With 10 seconds of averaging the SFC compass resolves a transverse field of 18~$\mu$G, corresponding to a directional resolution of 70~$\mu$rad in a field of 0.25 G, close to the Earth's field.
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All authors B. Wojtsekhowski, C. Cuevas, R. Dawson, W. Henry, N. Liyanage, G. Ron, J. Wilson

Instrumentation and Detectors

Cross-Detector Transfer Learning with Parnassus: From ALEPH to SLD

Ya-Feng Lo, Chi Lung Cheng and Benjamin Nachman

Parnassus is a fast detector-simulation and reconstruction framework that maps truth-level particles directly to reconstructed particles. In this work, we investigate cross-detector transfer learning by adapting a Parnassus model for the ALEPH detector to the SLD detector. ALEPH and SLD have similar detector responses, as they were both targeting hadronic $Z$-pole $e^+e^-$ events, while differing substantially in the underlying detector technology, reconstruction, and archived data representation. We initialize the SLD particle model with weights learned on ALEPH, fine-tune it on SLD, and compare it with the same architecture trained directly on SLD. The ALEPH-initialized model gives substantially improved particle- and jet-level agreement with the SLD reference, including a factor of 5.2 improvement in the charged-particle angular response and an improvement in the jet angular resolution from $1.73$ to $1.15$ times the SLD reference. The results show that detector-response information learned on ALEPH can be reused when modeling SLD and motivate reusable pretrained Parnassus models for legacy $e^+e^-$ detectors, which is especially critical for experiments without access to the original software pipeline. With this paper, we also release an AI-ready version of simulated SLD $e^+e^-$ events.
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Instrumentation and Detectors

Constraint-Traceable Liquid-Nitrogen Dewar Design for Low-Noise HTS-SQUID Magnetometry

Xinmin Shi, Bingke Xiang, Lingtong Hou et al. (+9 more)

Compact high-temperature superconducting quantum interference device (HTS-SQUID) magnetometers require a liquid-nitrogen Dewar that balances operating duration against instrument-envelope and mass constraints. Here we introduced a constraint-traceable design workflow in which body radius and neck-length fraction were scanned under fixed outer-envelope volume and geometry-based mass limits. The longest-duration feasible grid point lay adjacent to the 3.85 kg and 550 mm constraint intersection, predicting 224 h hold time from a body-only initial fill to a residual liquid depth of 10 mm. A reference Dewar was experimentally monitored for 137.3 h, consuming 1.22 L liquid-nitrogen of its initial inventory. A thermal model calibrated over the first 40 h reproduced the remaining 97.3 h. Device measurements at liquid-nitrogen temperature showed a superconducting transition and Fraunhofer-like junction response, a maximum voltage-modulation depth of 36.2 $\mu$V, and a median noise level of 41.5 fT Hz$^{-1/2}$ from 100 to 1000 Hz. These results establish a reproducible method for selecting Dewar geometry under coupled constraints and demonstrate compatibility with long-endurance and low-noise HTS-SQUID magnetometer systems.
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All authors Xinmin Shi, Bingke Xiang, Lingtong Hou, Wanjuan Tang, Geming Zhang, Shiqun Liu, Ruonan Wang, Yibo Wang, Zhiqiang Cao, Xueshen Wang, Xueying Zhang, Xiaoyang Lin

Saturday 12 September

Instrumentation and Detectors

Demonstrating the thermal noise limit in a backaction-free bulk acoustic wave resonator chain for gravitational wave detection

G. Albani, M. Borghesi, L. Canonica et al. (+14 more)

We report the full sub-Kelvin characterization of the BAUSCIA high-frequency gravitational-wave antenna, based on cryogenic Bulk Acoustic Wave resonators coupled to SQUID amplifiers for signal readout. The end-to-end performance analysis of the experimental chain, from the sensor to the DAQ, demonstrates that resonator thermal noise dominates the noise budget at temperatures well below 100 mK for all investigated modes. The measurements also verify proper thermalization of the resonator modes and rule out significant SQUID backaction on the strain sensor, confirming that the system operates close to its fundamental limits with comparable resonator thermal noise and additive readout noise. From this characterization, we derive projected strain sensitivities in the range $1$–$10 \times 10^{-21}\,\mathrm{Hz}^{-1/2}$ for several resonant frequencies between 5 and 20~MHz, with corresponding fundamental thermal limits in the range $0.7$–$1.4 \times 10^{-21}\,\mathrm{Hz}^{-1/2}$. Equipped with three resonators and synchronized to an absolute global time reference for multi-site coincidences, the antenna is ready to enter a pilot science run.
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All authors G. Albani, M. Borghesi, L. Canonica, R. Carobene, F. De Guio, M. Faverzani, N. Ferreiro Iachellini, E. Ferri, R. Gerosa, A. Ghezzi, A. Giachero, D. Labranca, L. Mariani, R. Maifredi, A. Nucciotti, D. Rozza, T. Tabarelli de Fatis

Friday 11 September

Instrumentation and Detectors

Surface Commissioning and Performance of the sMDT Muon Chambers for the ATLAS HL-LHC Upgrade

Jiajin Ge, Elena Voevodina, Hubert Kroha et al. (+21 more)

To improve the first-level muon trigger efficiency at the HL-LHC, the Monitored Drift Tube (MDT) chambers in the inner small sectors of the ATLAS Barrel Muon Spectrometer will be replaced with integrated modules of small-Diameter Muon Drift Tube (sMDT) and Resistive Plate Chambers (RPCs). This paper reports on the surface commissioning of 102 new sMDT chambers at CERN in 2025 following the installation of the final front-end electronics, including the new Amplifier-Shaper-Discriminator (ASD), Time-to-Digital Converter (TDC) chips, and Chamber Service Module (CSM) developed for the HL-LHC. The commissioning included measurements of gas leak rates and high-voltage dark currents, tests of the integrated planarity monitoring system, noise characterization, and measurements of detector efficiency and spatial resolution using cosmic rays. Fewer than 0.1% of the 49152 tubes were found to be non-functional due to broken sense wires or gas leaks. The chambers exceed the ATLAS design requirements, with gas leak rates a factor of five below the specified limit of $9.3\times 10^{-3}~\mathrm{mbar\cdot liter/s}$ per chamber, dark currents of only around 0.2~nA per tube, average channel noise hit rates below 30~Hz, and average drift tube efficiency and spatial resolution of 99% and $82~\mu\mathrm{m}$, respectively, at an effective threshold of 15 primary electrons.
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All authors Jiajin Ge, Elena Voevodina, Hubert Kroha, Tatiana Azaryan, Kwok Ching Cheung, Tiesheng Dai, Edward Diehl, Claudio Ferretti, Yuxiang Guo, Oliver Kortner, Chihao Li, Chun Kit Lo, Nick Meier, Emmett Salzer, Can Suslu, Cecilia Vanesa Imthurn, Samuel Hugo Venetianer, Curtis Weaverdyck, Chuanshun Wei, Bastian Michael Wesely, Ruslan Yakubovych, Bing Zhou, Junjie Zhu, Jörg Zimmermann

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

Agent-authored deposition recipes for X-ray multilayer mirrors: schema-bound LLM control of a magnetron sputtering system with reflectivity-verified outcomes

Oleksiy V. Penkov, Haoyu Fu, Yueying Zhan et al. (+2 more)

Periodic multilayer mirrors for X-rays require a layer period controlled to about 0.1 nm, set by deposition rates held in the laboratory's own notebook. A supervising model session gave a large language model agent a target multilayer specification and calibration constants derived from a laboratory archive. The agent authored recipes in the magnetron sputtering system's native recipe language and submitted them through a Model Context Protocol bridge of 17 tools in three tiers, with enforcement in the control application. The target was a 30-bilayer Ru/C multilayer with a period of 6.85 nm, a pair chosen because each period is fitted as two layers. The agent could read and write only its own working project, so it could alter neither the calibration record nor the measurements that scored it. We scored mirrors by X-ray reflectivity and fixed the 3% acceptance threshold on relative period difference before deposition. Across four scored depositions, the relative period difference fell from 20% on the calibration as given to 2.26% after one measured-feedback iteration and 0.79% after a second. We identified sixteen failure modes of the agent-facing interface. The result is bounded to the period, pair, and chamber observed.
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All authors Oleksiy V. Penkov, Haoyu Fu, Yueying Zhan, Pengyuan Wu, Jiong Jin

Instrumentation and Detectors

An integrated readout system for parallel-plate avalanche counter and multi-wire drift chamber at HIAF-HIRIBL

E. Q. Liu, T. S. Huang, Z. X. Ma et al. (+14 more)

A newly developed, highly-integrated multi-channel front-end readout system – FEAM-256 – is presented for use with position-sensitive gaseous detectors, including parallel-plate avalanche counters (PPACs) and multi-wire drift chambers (MWDCs). The system's position resolution was characterized using both an $\alpha$ source and cosmic-ray muons. Intrinsic position resolutions of 320 $\mu$m for the PPAC, and 424 $\mu$m for the MWDC were achieved. Designed specifically for integration into the data-acquisition infrastructure at the High-Rigidity radioactive Ion Beam Line (HIRIBL) of China's High Intensity heavy-ion Accelerator Facility (HIAF), FEAM-256 enables seamless incorporation of PPAC and MWDC detectors into the HIRIBL experimental setup.
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All authors E. Q. Liu, T. S. Huang, Z. X. Ma, Z. P. Sun, L. Li, H. J. Ong, H. Wang, S. Terashima, L. M Duan, H. R Yang, Y. Qian, F. S. Shi, Y. N. Song, B. H. Sun, X. D. Xu, J. W. Yan, Z. C. Zhang

Thursday 10 September

Instrumentation and Detectors

Agentic TCAD Calibration Workflow for Oxide Semiconductor Transistors

Gyujun Jeong, Junmo Lee, Sungwon Cho et al. (+11 more)

Experimental TCAD calibration is essential for predictive technology modeling of emerging oxide semiconductor transistors. However, it remains time-consuming and expert dependent because of model ambiguity. Multiple physical models and parameter sets can reproduce the same measured transfer characteristics, while local fitting alone cannot uniquely identify the underlying device physics. We present the first demonstration of an agentic TCAD calibration workflow for a fabricated bottom-gate In–W–O (BG-IWO) transistor. Starting from the measured transfer curve and device information, the workflow uses measurement–TCAD residuals and local sensitivity tests to select bounded parameter corrections or evaluate additional physical models, and accept only updates that improve device metrics. The LLM agent orchestrates the workflow, while Sentaurus governs the device physics. For the 2%-W reference device, five agent-suggested updates yield a fixed calibrated model, reducing the multi-metric device objective $J$ by 14.3$\times$. Maximum $V_{\mathrm{th}}$/$I_{\mathrm{on}}$ errors are 36.1~mV/0.022 decade for varying-drain-bias tests and 46.2~mV/0.062 decade for varying-channel-length tests, demonstrating model transferability across bias and geometry rather than a local parameter fit. W-composition tests provide process-sensitive insight. This agentic workflow provides a faster route to model development for emerging device technologies.
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All authors Gyujun Jeong, Junmo Lee, Sungwon Cho, Woohyun Hwang, Kwangyou Seo, Suhwan Lim, Wanki Kim, Daewon Ha, Rishi Ranade, Kihang Youn, Ram Cherukuri, Yiyi Wang, Asif Khan, Shimeng Yu

Instrumentation and Detectors

Fast BIB simulation at a future Muon Collider with generative machine learning

Radha Mastandrea, Shiyu Peng, Benjamin Rosser et al. (+1 more)

Beam-induced background (BIB) from muon decay products will be an overwhelming and unavoidable background at a future Muon Collider. In order to develop robust event reconstruction algorithms, we need large amounts of accurate BIB simulation to test on. BIB simulation is currently compute-limited: the simulated sample presently used for BIB overlay, which statistically represents approximately $10\%$ of a single unique event's worth of simulated BIB, requires on the order of $10^6$ HS23$\cdot$hours to generate and occupies approximately $100$ GB on disk. In this work, we develop the first machine learning models for fast BIB generation in tracking detectors. We consider two classes of architectures: a slower but higher-fidelity tabular diffusion model, and a faster but lower fidelity circular spline flow model. We find that both classes of architectures produce BIB hits and tracks that closely resemble those of available full simulation hits and tracks, and that the machine learning models can produce BIB in over an order of magnitude less time than what is needed to produce full simulation BIB. We release the model weights with the paper so that the Muon Collider community can use these fast BIB hits for future R&D.
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All authors Radha Mastandrea, Shiyu Peng, Benjamin Rosser, Matt LeBlanc

Instrumentation and Detectors · Cross-listed from quant-ph

Computational framework for quantum state tomography of spin ensembles

Jiwoo Seo and Vesna F. Mitrović

We present Tomography-NMR, an open-source Python package that reconstructs quantum density matrices from spectroscopic measurement data. The package implements a complete analysis pipeline for two-qubit quantum state tomography based on the product operator formalism: raw time-domain signals are Fourier-transformed into frequency-domain spectra, spectral peak intensities are mapped to expansion coefficients of the density matrix, and the full quantum state is reconstructed. Three integration methods are provided for different use cases: direct peak height measurement and fixed-parameter numerical integration require no theoretical reference and are suited to unknown states, achieving fidelities of approximately 98% on a benchmark set of known states, while a systematic parameter optimization against a known target state achieves reconstruction fidelities exceeding 99% for the same benchmark states. While the detailed theoretical framework for quantum state tomography is well established, the practical procedures for extracting density matrices from experimental spectra are often inadequately documented in the literature and obscured within proprietary software. This package addresses that gap by providing a fully transparent, reproducible implementation of every analysis step, from spectral preprocessing to density matrix visualization. The software has been validated on experimentally prepared two-qubit states measured via nuclear magnetic resonance (NMR) spectroscopy of coupled $^{31}$P nuclei. Average reconstruction fidelities range from 0.975 to 0.995 across a benchmark set of 20 two-qubit states, including the computational basis states, Bell states, and the outputs of three fundamental quantum gates (CNOT, H, and T). Although developed for NMR, the modular architecture facilitates adaptation to other spectroscopic platforms and alternative measurement protocols.
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Instrumentation and Detectors · Cross-listed from eess.SP

Multi-Threshold Sampling: Signal Space, Sampling Operators, and First Recorded Crossing-Time Distributions

Ao Qiu and Qingguo Xie

Multi-threshold (MT) sampling records crossing times at selected thresholds for parameter estimation and waveform reconstruction. We develop a mathematical framework that defines the signal space and sampling operators and maps the signal distribution to the distribution of recorded crossings. The framework distinguishes model mismatch, signal noise, threshold mismatch, and threshold noise. Finite point measures accommodate variable crossing counts and preserve multiplicity after time quantization. Stochastic crossing, timing, and selection operators and their associated Markov kernels describe the sampling process. For nonhomogeneous Poisson photon arrivals and deterministic MT sampling, we derive the exact cumulative distribution function (CDF) of the first recorded crossing time at a specified threshold within a recorded-time interval. Under additional regularity and local monotonicity conditions, this CDF admits a one-dimensional Fourier representation. For a scintillation pulse model, numerical CDFs and standard deviations of the first recorded crossing time agree with independent Monte Carlo simulations, providing a quantitative basis for comparing threshold settings. The framework provides a foundation for MT performance evaluation, parameter estimation, waveform reconstruction, and sampler design.
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Instrumentation and Detectors

High-Speed Semi-FE Readout Module for ATLAS MDT at HL-LHC: Design and Production-Level Characterization

Yao Teng, Xueye Hu, Yuxiang Guo et al. (+5 more)

The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) introduces increased demands on the ATLAS Muon Spectrometer, particularly in terms of data throughput, timing distribution and system reliability. The Phase-II Chamber Service Module (CSM) is a key component of the upgraded Monitored Drift Tube (MDT) trigger and readout system, providing a high-speed interface between the front-end electronics and the backend systems. This paper describes the design and implementation of the Phase-II CSM, together with its validation. The results show that the CSM supports two independent optical uplinks, each operating at a line rate of 10.24 Gbps, together with clock distribution and slow control in the expected operating environment. Integration with small-diameter MDT (sMDT) chambers and tests with the prototype L0MDT trigger system are also presented. The CSM boards are now in production and will be used for installation and integration during the upcoming LHC Long Shutdown.
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All authors Yao Teng, Xueye Hu, Yuxiang Guo, Shaghayegh Emami, Thomas Baer, Thomas Schwarz, Junjie Zhu, Bing Zhou

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

Measuring chiral phonons

Rahul Rao, Hanyu Zhu, Nicholas Kotov et al. (+7 more)

Chiral phonons are quantized vibrations where the atomic motion in a solid breaks improper rotation symmetries. In many cases, chiral phonons possess angular momenta and are therefore selective to circularly polarized light. Both fundamental and applied research efforts on chiral phonons have been gaining increasing attention owing to their importance in a variety of fields including spintronics, spin-selective chemical reactions, thermal transport, quantum information processing and biosensing, where the bi-directional spin-lattice coupling enabled by chiral phonons can be harnessed in new ways, and potentially lead to new functionalities. Thus far, the studies of chiral phonons across diverse materials platforms have evolved largely independently within these fields, but the experimental techniques are often interrelated. In this perspective, we present a detailed description, as well as advantages and disadvantages of the current approaches for experimentally measuring chiral phonons in chiral and achiral materials. We conclude with a discussion of new methods for measuring chiral phonons. Ultimately, this work seeks to offer an experimental guide for systematically investigating the properties of chiral phonons in various materials systems and applications.
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All authors Rahul Rao, Hanyu Zhu, Nicholas Kotov, Thuc T. Mai, Maria F. Muñoz, Dali Sun, Jun Liu, Wonjin Choi, Renee R. Frontiera, Angela R.H. Hight Walker

Wednesday 9 September

Instrumentation and Detectors

Real-Time SiPM Pulse Deconvolution for a High-granularity Dual-readout Calorimeter with Neutral Networks

Spencer Allen, Matteo Cremonesi, Jordan Damgov et al. (+6 more)

The High-Granularity Dual-Readout Calorimeter (HG-DREAM) designed for FCC-ee aims to achieve unprecedented energy resolution through fine three-dimensional shower imaging, simultaneous measurement of Cherenkov and scintillation signals, and machine learning capabilities. A key enabling technology is longitudinal segmentation via timing measurements, where multiple energy deposits along optical fibers are distinguished by the arrival times of Cherenkov photons. We present quantized one-dimensional convolutional neural networks that predict pulse locations directly from 80-sample, 16 ns waveforms digitized at 200 ps, and evaluate their implementation in front-end electronics. Three architectures, a compact baseline and two variants using dilation and stride to reach the $\sim$ 20-sample receptive field set by the SiPM pulse width, achieve ROC AUC above 0.95 with four to eight filters per layer. Fixed-point quantization to a $<$16,8$>$ baseline costs less than $10^{-3}$ in AUC relative to the floating-point reference. Applied to pairwise deposits, the smallest model separates two pulses with better than 95% probability at longitudinal separations of 20 cm and above. Synthesized at 400 MHz, this model uses 9663 LUT on a Xilinx XCVU13P FPGA and occupies $\sim$ 18500 $\mu$$m^2$ in TSMC 28 nm CMOS with reconfigurable weights. Assuming a triggered readout architecture for FCC-ee, the $\sim$ 500 kHz Z-pole trigger rate will be the most stringent throughput requirement across all FCC-ee operating modes. The ASIC implementation of the model sustains 4.8 MHz, exceeding the 0.5 MHz requirement by an order of magnitude, while the reconfigurable-weight FPGA implementation fails to do so. Sustaining the 40 MHz FCC-ee Z-pole bunch-crossing frequency in the triggerless architecture is not feasible with the models developed and the hardware targeted in this work.
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All authors Spencer Allen, Matteo Cremonesi, Jordan Damgov, Erdem Yigit Ertorer, Janna Goodman, Giuseppe Di Guglielmo, James Hirschauer, Shuichi Kunori, Peter Meiring

Instrumentation and Detectors

Mitigating Sensor Cracking using the Interposer Strategy in the ATLAS ITk Strip Detector

ATLAS ITk Strips Collaboration

This paper introduces the strategy of using an interposing layer to mitigate thermal-stress-induced fracturing of silicon sensors in ATLAS ITk Strip modules. This strategy involves a change in the module design in which layers of soft adhesive and a kapton separator, known as an interposer, are added to the module stack-up to decouple thermal stresses. This paper discusses the interposer design and its implementation in the ATLAS ITk Strip barrel, including material tests to validate the additional components, the development of new processes to integrate the new layers into the module assembly workflow, results from design validation and quality control testing of prototype interposed modules, and studies indicating that the new design significantly reduces the thermal stress experienced by the sensor. Tests of prototype support structures loaded with interposed modules have shown no sensor fractures in the relevant temperature range for operation in ATLAS, resulting in the adoption of the interposer strategy as the primary sensor cracking mitigation in the ATLAS ITk Strip barrel.
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