Results for “timing detector” — Page 69

DOE OSTI2021

Demonstration of Energy-Resolved γ-Ray Detection at Room Temperature by the CsPbCl 3 Perovskite Semiconductor

The detection of gamma-rays at room temperature with high-energy resolution using semiconductors is one of the most challenging applications. The presence of even the smallest amount of defects is sufficient to kill the signal generated from gamma-rays which makes the availability of semiconductors detectors a rarity. Lead halide perovskite semiconductors exhibit unusually high defect tolerance leading to outstanding and unique optoelectronic properties and are poised to strongly impact applications in photoelectric conversion/detection. Here we demonstrate for the first time that large size single crystals of the all-inorganic perovskite CsPbCl 3 semiconductor can function as a high-performance detector for gamma-ray nuclear radiation at room temperature. CsPbCl 3 is a wide-gap semiconductor with a bandgap of 3.03 eV and possesses a high effective atomic number of 69.8. We identified the two distinct phase transitions in CsPbCl 3 , from cubic (Pm-3m) to tetragonal (P4/mbm) at 325 K and finally to orthorhombic (Pbnm) at 316 K. Despite crystal twinning induced by phase transitions, CsPbCl 3 crystals in detector grade can be obtained with high electrical resistivity of similar to 1.7 X 10 9 Ω∙cm. The crystals were grown from the melt with volume over several cubic centimeters and have a low thermal conductivity of 0.6 W m -1 K -1 . The mobilities for electron and hole carriers were determined to similar to 30 cm 2 /(V s). Using photoemission yield spectroscopy in air (PYSA), we determined the valence band maximum at 5.66 +/- 0.05 eV. Under gamma-ray exposure, our Schottky-type planar CsPbCl 3 detector achieved an excellent energy resolution (similar to 16% at 122 keV) accompanied by a high figure-of-merit hole mobility-lifetime product (3.2 x 10 -4 cm 2 /V) and a long hole lifetime (16 mu s). The results demonstrate considerable defect tolerance of CsPbCl 3 and suggest its strong potential for gamma-radiation and X-ray detection at room temperature and above.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Synchrotron characterization of high-Z, current-mode x-ray detectors

Fast x-ray detectors are critical tools in pulsed power and fusion applications, where detector impulse response of a nanosecond or better is often required. Semiconductor detectors can create fast, sensitive devices with extensive operational flexibility. There is typically a trade-off between detector sensitivity and speed, but higher atomic number absorbers can increase hard x-ray absorption without increasing the charge collection time, provided carriers achieve high velocity. This paper presents x-ray pulse characterization conducted at the Advanced Photon Source of x-ray absorption efficiency and temporal impulse response of current-mode semiconductor x-ray detectors composed of Si, GaAs, and CdTe.

47 OTHER INSTRUMENTATION↗

DOE OSTI2025

Luminosity measurement for lead-lead collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV in 2015 and 2018 at CMS

Measurements of the luminosity delivered to the CMS experiment during the lead-lead data-taking periods in 2015 and 2018 are presented for the first time. The collisions were recorded at a nucleon-nucleon center-of-mass energy of 5.02 TeV; the 2018 data sample is three times larger than the 2015 data sample. Three subdetectors are used: the pixel luminosity telescope, the forward hadron calorimeters, and the fast beam conditions monitor. The absolute luminosity calibration is determined using the van der Meer technique that relies on transverse beam separation scans. The dominant sources of uncertainty are the transverse factorizability of the bunch density profiles and, in 2015, the difference between the results obtained using various detectors. The total uncertainty in the integrated luminosity, including the stability of the calibrated subdetector response over time, amounts to 3.0% for 2015, 1.7% for 2018, and 1.6% for the combined data sample.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2022

Gravitational wave timing array

We describe the design of a gravitational wave timing array, a novel scheme that can be used to search for low-frequency gravitational waves by monitoring continuous gravitational waves at higher frequencies. We show that observations of gravitational waves produced by Galactic binaries using a space-based detector like LISA provide sensitivity in the nanohertz to microhertz band. While the expected sensitivity is several magnitudes worse than what can be achieved by pulsar timing arrays, it supplements other recent proposals for gravitational wave searches in the microhertz regime. This regime is below the frequencies to which LISA is directly sensitive, and above the frequency range generally targeted by pulsar timing array searches. Here, the low-frequency extension of sensitivity does not require any experimental design change to space-based gravitational wave detectors, and can be achieved with the data products that would already be collected by them.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2026

Detector Characterization for SuperCDMS Commissioning

Super Cryogenic Dark Matter Search (SuperCDMS) SNOLAB is a next generation direct detection experiment search ing for low mass dark matter using cryogenic germanium and silicon detectors operated at millikelvin temperatures. As the experiment begins its first commissioning data taking, establishing that the detectors respond to energy deposits in a stable, predictable way is a prerequisite for any future physics analysis. This work presents a study of detector stability for four SuperCDMS SNOLAB detectors, det 7 and det 15 (germanium), and det 11 and det 14 (silicon), using two data sets taken during early commissioning: dedicated Barium-133 calibration runs, which provide a known gamma ray energy reference at 356 keV, and low background runs, which record whatever background radiation the detectors see with no external source present. The Ba-133 data do not show a distinct, well localized line at the expected energy, and the low background data show a baseline that drifts and oscillates over time rather than remaining flat. This baseline instability appears consistently across multiple channels rather than being confined to one, suggesting a shared, detector wide cause rather than a single faulty channel. Together, these observations point to the detectors’ cryogenic support system as the likely source of the instability, since small temperature fluctuations introduced during normal operation of the cooling system could plausibly couple into the exquisitely temperature sensitive detectors. These results inform the ongoing commissioning effort by narrowing down where instability in the current data is originating from.

O'Hanlon, Viktoria M. [Skidmore Coll.; Fermilab]↗

DOE OSTI2026

Detector Characterization for SuperCDMS Commissioning

Super Cryogenic Dark Matter Search (SuperCDMS) SNOLAB is a next generation direct detection experiment search ing for low mass dark matter using cryogenic germanium and silicon detectors operated at millikelvin temperatures. As the experiment begins its first commissioning data taking, establishing that the detectors respond to energy deposits in a stable, predictable way is a prerequisite for any future physics analysis. This work presents a study of detector stability for four SuperCDMS SNOLAB detectors, det 7 and det 15 (germanium), and det 11 and det 14 (silicon), using two data sets taken during early commissioning: dedicated Barium-133 calibration runs, which provide a known gamma ray energy reference at 356 keV, and low background runs, which record whatever background radiation the detectors see with no external source present. The Ba-133 data do not show a distinct, well localized line at the expected energy, and the low background data show a baseline that drifts and oscillates over time rather than remaining flat. This baseline instability appears consistently across multiple channels rather than being confined to one, suggesting a shared, detector wide cause rather than a single faulty channel. Together, these observations point to the detectors’ cryogenic support system as the likely source of the instability, since small temperature fluctuations introduced during normal operation of the cooling system could plausibly couple into the exquisitely temperature sensitive detectors. These results inform the ongoing commissioning effort by narrowing down where instability in the current data is originating from.

O'Hanlon, Viktoria M. [Skidmore Coll.; Fermilab]↗

DOE OSTI2023

Generalizing to new geometries with Geometry-Aware Autoregressive Models (GAAMs) for fast calorimeter simulation

Generation of simulated detector response to collision products is crucial to data analysis in particle physics, but computationally very expensive. One subdetector, the calorimeter, dominates the computational time due to the high granularity of its cells and complexity of the interactions. Generative models can provide more rapid sample production, but currently require significant effort to optimize performance for specific detector geometries, often requiring many models to describe the varying cell sizes and arrangements, without the ability to generalize to other geometries. Here, we develop a geometry-aware autoregressive model, which learns how the calorimeter response varies with geometry, and is capable of generating simulated responses to unseen geometries without additional training. The geometry-aware model outperforms a baseline unaware model by over 50% in several metrics such as the Wasserstein distance between the generated and the true distributions of key quantities which summarize the simulated response. A single geometry-aware model could replace the hundreds of generative models currently designed for calorimeter simulation by physicists analyzing data collected at the Large Hadron Collider. This proof-of-concept study motivates the design of a foundational model that will be a crucial tool for the study of future detectors, dramatically reducing the large upfront investment usually needed to develop generative calorimeter models.

47 OTHER INSTRUMENTATION↗

DOE OSTI2025

Characterization of Pinhole Collimators for High-Resolution Gamma Imaging of Irradiated Fuel

Post-irradiation examination (PIE) of nuclear fuels requires imaging tools capable of resolving isotopic and spatial features with high throughput. This project contributes to a proof-of-concept effort aimed at advancing gamma emission tomography (GET) by evaluating novel fine-aperture pinhole collimators. Two Rose’s metal collimators, 100 µm (20° acceptance angle) and 350 µm (30° acceptance angle), were prototyped and characterized for their effectiveness in transporting gamma rays through the pinhole aperture. To support data collection, a Python-based data acquisition system was developed to coordinate a rotation stage, linear stage, and CZT detector, reducing latency in high-rate gamma event logging to one second per acquisition. Queue-based file writing enabled seamless real-time data capture for count rates up to 35,000 counts per second (cps). List-mode parsing algorithms were implemented to differentiate single and simultaneous gamma interactions for future tomographic reconstruction. Detector response was evaluated in both spectroscopy and list mode acquisition methods across varying source distances to confirm absolute and collimator efficiencies. Preliminary efficiency figures suggest effective collimation of gamma-rays with energies below 700 keV, with ~4% residual intensity through the aperture for Cs-137. The impact of collimator geometry on image quality is currently being evaluated. This groundwork supports the ongoing development of a sub mm resolution cone-beam CT system for imaging fuel phantoms, an essential step toward improving GET efficiency and accelerating nuclear fuel qualification efforts.

46 - INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AN↗

DOE OSTI2022

Real-Time Interactive 4D-STEM Phase-Contrast Imaging From Electron Event Representation Data: Less computation with the right representation

The arrival of direct electron detectors (DED) with high frame-rates in the field of scanning transmission electron microscopy has enabled many experimental techniques that require collection of a full diffraction pattern at each scan position, a field which is subsumed under the name four dimensional-scanning transmission electron microscopy (4D-STEM). DED frame rates approaching 100 kHz require data transmission rates and data storage capabilities that exceed commonly available computing infrastructure. Current commercial DEDs allow the user to make compromises in pixel bit depth, detector binning or windowing to reduce the per-frame file size and allow higher frame rates. This change in detector specifications requires decisions to be made before data acquisition that may reduce or lose information that could have been advantageous during data analysis. The 4D Camera, a DED with 87 kHz frame-rate developed at Lawrence Berkeley National Laboratory, reduces the raw data to a linear-index encoded electron event representation (EER). Here we show with experimental data from the 4D Camera that linear-index encoded EER and its direct use in 4D-STEM phase contrast imaging methods enables real-time, interactive phase-contrast from large-area 4D-STEM datasets. Furthermore, we detail the computational complexity advantages of the EER and the necessary computational steps to achieve real-time interactive ptychography and center-of-mass differential phase contrast using commonly available hardware accelerators.

4D-STEM↗

DOE OSTI2021

Neutrino event selection in the MicroBooNE liquid argon time projection chamber using Wire-Cell 3D imaging, clustering, and charge-light matching

An accurate and efficient event reconstruction is required to realize the full scientific capability of liquid argon time projection chambers (LArTPCs). The current and future neutrino experiments that rely on massive LArTPCs create a need for new ideas and reconstruction approaches. Wire-Cell, proposed in recent years, is a novel tomographic event reconstruction method for LArTPCs. The Wire-Cell 3D imaging approach capitalizes on charge, sparsity, time, and geometry information to reconstruct a topology-agnostic 3D image of the ionization electrons prior to pattern recognition. A second novel method, the many-to-many charge-light matching, then pairs the TPC charge activity to the detected scintillation light signal, thus enabling a powerful rejection of cosmic-ray muons in the MicroBooNE detector. A robust processing of the scintillation light signal and an appropriate clustering of the reconstructed 3D image are fundamental to this technique. In this paper, we describe the principles and algorithms of these techniques and their successful application in the MicroBooNE experiment. A quantitative evaluation of the performance of these techniques is presented. Using these techniques, a 95% efficient pre-selection of neutrino charged-current events is achieved with a 30-fold reduction of non-beam-coincident cosmic-ray muons, and about 80% of the selected neutrino charged-current events are reconstructed with at least 70% completeness and 80% purity.

3D imaging↗

DOE OSTI2021

NOvA as a Supernova Observatory

Extra-solar system neutrino astronomy was born in February 1987 when a supernova in a nearby satellite galaxy deposited a couple dozen neutrino events across three solar neutrino and nucleon decay experiments. This marked the first-ever observation of supernova neutrinos, as well as the first supernova in our galactic neighborhood visible to the naked eye in nearly 400 years. There is still much we do not know about the dynamics of these powerful explosions, but one thing is certain: neutrinos play a central role in driving a supernova. They also provide a unique opportunity for probing the interior conditions of a collapsing stellar core. Since 1987, the number of neutrino detectors around the world has grown. When the next supernova occurs, detectors must be ready to seize the moment and record data from this rare event that only happens a couple times per century. The NOvA experiment has been prepared for this for some time, but it has been unclear how well NOvA will be ab le to se parate supernova-like events from the large cosmogenic backgrounds and extract meaningful physical insight. In this thesis, I show that the cosmic-induced backgrounds in the NOvA detectors---especially the far detector---can be reduced to an acceptable level for core-collapse supernovae within $\sim$15 kpc and that a determination of the neutrino mass ordering can be made for nearby supernovae under certain conditions. This thesis paves the way for future sensitivity studies and eventual analyses of real supernova data, and shows that NOvA's liquid scintillator neutrino detectors are a capable supernova observatory.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2021

NOvA as a Supernova Observatory

Extra-solar system neutrino astronomy was born in February 1987 when a supernova in a nearby satellite galaxy deposited a couple dozen neutrino events across three solar neutrino and nucleon decay experiments. This marked the first-ever observation of supernova neutrinos, as well as the first supernova in our galactic neighborhood visible to the naked eye in nearly 400 years. There is still much we do not know about the dynamics of these powerful explosions, but one thing is certain: neutrinos play a central role in driving a supernova. They also provide a unique opportunity for probing the interior conditions of a collapsing stellar core. Since 1987, the number of neutrino detectors around the world has grown. When the next supernova occurs, detectors must be ready to seize the moment and record data from this rare event that only happens a couple times per century. The NOvA experiment has been prepared for this for some time, but it has been unclear how well NOvA will be ab le to se parate supernova-like events from the large cosmogenic backgrounds and extract meaningful physical insight. In this thesis, I show that the cosmic-induced backgrounds in the NOvA detectors---especially the far detector---can be reduced to an acceptable level for core-collapse supernovae within $\sim$15 kpc and that a determination of the neutrino mass ordering can be made for nearby supernovae under certain conditions. This thesis paves the way for future sensitivity studies and eventual analyses of real supernova data, and shows that NOvA's liquid scintillator neutrino detectors are a capable supernova observatory.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2023

Advancements of the nSpec system

For this study, a new characterization of the detector response for the EJ301 liquid scintillator based nSpec system has been conducted at the Los Alamos Neutron Science Center. The new characterization was accomplished in two orders of magnitude less time and with better statistics than the previous characterization. The new and old characterization methods were compared by conducting both types of characterization on two detectors (one EJ301 and one EJ301D). The two methods show consistent results and compare well to results previously published in the literature; however, the results from the characterization of the original nSpec detector show discrepancies that have been identified as being caused by oxygen being absorbed into the detector due to a leak. The new characterized detector response shows improved spectrum unfolding performance than the previous characterization. The cross talk of the detector system was also characterized as a function of incident neutron energy and found to have a negligible impact on spectrum unfolding results. Alternative materials (EJ301D and stilbene) were also characterized in a first step towards an upgraded system. The different materials show little difference in unfolding performance, but the comparison is ongoing. A SiPM based stilbene detector was used to evaluate the use of SiPMs in a future system upgrade. The SiPM provides adequate performance, but the custom SiPM readout results in a much longer pulse width than PMT based systems. The measured light output of the SiPM based stilbene compares well with the results in literature. Future work will look at additional materials (deuterated stilbene and organic glass) and optimizing the SiPM readout to decrease the pulse width.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2025

Solar Neutrino Detection with a Pixelated Liquid-Argon Time Projection Chamber

This thesis presents a study of low-energy solar neutrino detection using large-scale LArTPCs, focussing on novel pixelated readout technologies. Solar neutrinos offer a unique probe of fundamental neutrino properties and solar physics, but their detection in the MeV range is challenged by backgrounds. We investigate two complementary technologies: SoLAr, which integrates LArPix-based pixelated charge collection with Silicon Photomultipliers (SiPMs) in a hybrid anode design for simultaneous charge and light detection; and Q-Pix, a triggerless pixelated readout architecture based on charge integrate-reset circuits with local clocks, where Reset Time Differences encode ionisation waveforms via time-to-charge conversion. Two SoLAr prototypes were developed and operated, demonstrating VUV-sensitive SiPM performance in liquid argon and accurate charge-light signal matching with a charge detection threshold of $\sim 100 \mathrm{keV}$. We also implement a complete simulation and reconstruction framework, incorporating realistic detector geometry, electron transport, readout response, and detailed signal and background models, including intrinsic argon and radon progeny, as well as site-specific $\gamma$-ray and neutron fluxes. For Q-Pix, we demonstrate that with a pixel size of $4\times 4$ mm$^2$ and a reset threshold of 1 fC ($\sim 0.1475$ MeV), full-scale operation produces data volumes below 1 PB per 10 ktonne-year. For SoLAr, assuming a shielded DUNE-like detector and 100 ktonne-year exposure, we project uncertainties of $0.90\times 10^{-5}$ eV$^2$ on $\Delta m^2_{21}$ and 0.033 on $\sin^2\theta_{12}$, improving to $0.46\times 10^{-5}$ eV$^2$ and 0.025 with 400 kilotonne-year. At this higher exposure, we also obtain a day–night flux asymmetry at the level of $( -5.6 \pm 3.6 ) \%$. Combining Monte Carlo modelling, hardware validation, and advanced reconstruction techniques, this work establishes a path toward next-generation ktonne-scale LArTPCs as observatories for precision solar neutrino physics.

Ruiz Ferreira, Guilherme [Manchester U.] (ORCID:00↗

DOE OSTI2025

Online Electron Reconstruction at CLAS12

Online reconstruction plays a crucial role in monitoring and in real-time analysis of high energy and nuclear physics experiments. A vital aspect of reconstruction algorithms is particle identification, which combines information from various detector components to determine the type of particle. Electron identification is particularly significant in electro-production nuclear physics experiments like the CLAS12 spectrometer at Jefferson Laboratory as it is essential in data recording. A machine learning approach has been developed for CLAS12 experiments to reconstruct and identify electrons by combining raw signals from multiple detector components at the data acquisition level. This method achieves high electron identification purity while maintaining nearly 100% efficiency. Furthermore, the machine learning tools operate at rates exceeding data acquisition speed, enabling the real-time electron reconstruction. This advancement significantly improves online analyses and monitoring capabilities for CLAS12 experiments.

Tyson,, Richard [Thomas Jefferson National Acceler↗

DOE OSTI2025

Super-Resolution Ptychography with Small Segmented Detectors

To overcome the spatial resolution limit set by aperture-limited diffraction in traditional scanning transmission electron microscopy, microscopists have developed ptychography enabled by iterative phase retrieval algorithms and high-dynamic-range pixel array detectors. Current detector designs are limited by the data rate off chip, so a high-pixel-count detector has a proportionally lower frame rate than the few-segment detectors used for differential phase contrast (DPC) imaging. This slower acquisition speed leads to heightened vulnerability to scan noise, drift, and potential sample damage. This creates opportunities for repurposing fast segmented detectors for ptychography by trading a reduction in reciprocal space pixels for an increase in real space pixels. Here, we explore a strategy of oversampling in real space and instead apply detector pixel upsampling during the reconstruction process. Further, we demonstrate the viability of achieving super-resolution ptychography on thin objects using only 2 × 2 detector pixels, surpassing the resolution of integrated DPC (iDPC) imaging. With optimization using simulated datasets and experiments on MoTe 2 /WSe 2 bilayer moiré superlattices, we achieved super-resolution ptychography reconstructions under rapid acquisition conditions (37.5 pA, 1 μs dwell time), yielding over 50% improvements in contrast and information limit compared to annular dark field and iDPC imaging on the same detectors.

2D materials↗

DOE OSTI2024

MPGD Trackers in the ePIC Detector at the EIC

The future Electron-Ion Collider (EIC) at Brookhaven National Laboratory will collide polarized electrons with polarized proton/ions. The electron ? Proton / Ion Collider (ePIC) Experiment is the EIC general-purpose detector aiming at delivering the full physics program of the EIC. This unique environment imposes stringent requirements on the tracking system needed for the measurement of the scattered electron and charged particles produced in the collisions at the EIC. The central tracker of the ePIC detector has silicon layers for tracking and vertexing based on MAPS technology, which are complemented by large Micro-Pattern Gaseous Detector (MPGD) trackers in the barrel and in both the electron and hadron end cap regions. The MPGD layers provide fast timing (10-20 ns) and additional hit points (150 µm) for pattern recognition during track finding. Two MPGD technologies are used in ePIC central trackers: cylindrical Micromegas for the barrel inner tracker and planar thin-gap GEM-µRWELL hybrid detector for the barrel outer tracker and the end cap disks. In this talk, we will introduce these two technologies in the context of ePIC and we will discuss the ongoing R&D efforts to address the requirements. Finally, we will discuss the plans and timeline for the production and testing and commissioning of the MPGD trackers for the installation in the ePIC detector.

Gnanvo, Kondo↗

DOE OSTI2023

In-Pixel Readout IC with compact in-pixel ADC for Pixel detectors at HL LHC

The prototype Smart Pixel concept test chip (SP28), designed in a CMOS 28 nm bulk process, is a proof of concept readout integrated circuit (ROIC) designed for a future Phase III High Luminosity upgrade of the Large Hadron Collider. It employs a synchronous analog to digital converter (ADC) for the front-end design, with signal processing and data conversion within a single bunch crossing of 25 ns. It is therefore capable of accurately detecting hits occurring in consecutive bunch crossings, without off-time registration of events and pileup insensitivity, making it particularly suitable for the inner most layers of the vertex detector. The ROIC consists of a matrix of 32 × 16 pixels, each 25 × 25 µm 2 in size. Each pixel contains a charge sensitive preamplifer with leakage current compensation, three auto-zero comparators for a 2-bit fash-type ADC. The total power consumption is approximately 5 µW per pixel. The measured noise at the output of all the hit comparators across the ROIC is < 90 e- with threshold dispersion < 45 e-RMS, which allows an in-time threshold setting of ≈ 475 e-.

Parpillon, Benjamin↗