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All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

The brighter-fatter effect in the JWST MIRI Si:As IBC detectors: I. Observations, impact on science, and modeling

Context.The Mid-Infrared Instrument (MIRI) on board theJames WebbSpace Telescope (JWST) uses three Si:As impurity band conduction (IBC) detector arrays. The output voltage level of each MIRI detector pixel is digitally recorded by sampling up the ramp. For uniform or low-contrast illumination, the pixel ramps become nonlinear in a predictable way, but in areas of high contrast, the nonlinearity curve becomes much more complex. The origin of the effect is poorly understood and currently not calibrated out of the data. Aims.We provide observational evidence of the brighter-fatter effect (BFE) in MIRI conventional and high-contrast coronagraphic imaging, low-resolution spectroscopy, and medium-resolution spectroscopy data, and we investigate the physical mechanism that gives rise to the effect on the MIRI detector pixel raw voltage integration ramps. Methods.We used public data from the JWST/MIRI commissioning and Cycle 1 phase. We also developed a numerical electrostatic model of the MIRI detectors using a modified version of the publicPoisson_CCDcode. Results.We find that the physical mechanism behind the BFE manifesting in MIRI data is fundamentally different to that of charge-coupled devices and photodiode arrays such as the Hawaii-XRG near-infrared detectors used by the NIRISS, NIRCam, and NIRSpec instruments on board JWST. Observationally, the BFE makes the JWST MIRI data yield 10–25% larger point sources and spectral line profiles as a function of the relative level of de-biasing of neighboring detector pixels. This broadening impacts the MIRI absolute flux calibration, time-series observations of faint companions, and point spread function modeling and subtraction. We also find that the intra-pixel 2D profile of the shrinking Si:As IBC detector depletion region directly impacts the accuracy of the pixel ramp nonlinearity calibration model.

Astronomy & Astrophysics↗
DOE OSTI2026

Characterization of Low-energy Ionization Signals in Silicon Detectors for the Nab Experiment

The Nab (Neutron a b) experiment is designed to measure the beta-antineutrino angular correlation in free neutron 𝛽 decay with an ultimate precision goal of 0.1%, providing input for tests of Cabibbo-Kobayashi-Maskawa matrix unitarity. This measurement is performed via detection of electrons and protons in delayed coincidence using custom large-area segmented silicon detectors. We present the characterization of one such detector system to establish the proton energy and timing response, using a dedicated proton accelerator. The detected proton peak was studied for 25, 30, and 35 keV incident protons on a set of detector segments and multiple cooling cycles over a one-year period. Ionization losses were consistent with models of the detector dead layer with thicknesses less than 100 nm. The detected proton peak was stable within the uncertainty from energy calibration (0.25 keV). The rise times of detector pulses from 109Cd and 113Sn conversion electron sources were used to extract the impurity density profile and establish a precise model for the detector timing response. The observed impurity density profile varied from (2±2)×109/cm3 at the center to (26±2)×109/cm3 at the edge. This impurity density profile was then used to characterize systematic effects in proton time-of-flight measurements due to detector pulse-shape effects; the resultant proton timing systematic uncertainties were below 0.3 ns, which is sufficient for the Nab experiment.

Taylor, RJ [North Carolina State University]↗
DOE OSTI2024

DRiFT Current Mode, Trigger Settings and Flexible Detector Specifications Applied to Scintillator Arrays

MCNP radiation transport output is post-processed by DRiFT, a Detector Response Function Toolkit to simulate detailed nuclear instrumentation response. DRiFT can be used to assess the performance and potential limitations of scintillator, gas, and semiconductor detectors under a variety of simulated conditions not easily achievable in a laboratory setting. This work describes new updates in DRiFT for scintillator simulations which focus on the capability to simulate scintillators in current mode, an expansion of trigger options, and the ability to customize individual detector properties in a simulation. These improvements are designed to facilitate the ability to model large arrays of scintillator detectors with higher fidelity than was previously possible and are demonstrated in three examples. The first shows the difference between operating DRiFT in current and pulse mode. In the second example, which is intended to demonstrate deviations in individual detector performance, each detector has properties (PMT gain, optical transport, scintillation yield, etc.) that vary between detectors and are specified in DRiFT. A final example examines how DRiFT could be used to optimize digitizer settings in high rate measurements with split signals using the new common trigger option.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Constructing Data-Driven Predictions at the Far Detector for NOvA's Neutrino Oscillation Analysis.

NOvA, is a two-detector, long-baseline neutrino oscillation experiment located at Fermilab, Batavia, IL, USA. It is designed primarily to constrain neutrino oscillation parameters using $\nu_\mu \ (\bar{\nu}_\mu)$ disappearance and $\nu_e \ (\bar{\nu}_e)$ appearance data. The Neutrinos at Main Injector (NuMI) beamline at Fermilab provides a high purity 900 KW intense beam of neutrinos and anti-neutrinos to NOvA. The NOvA Near Detector, located 100m underground and 1km away from the beam source, observes the un-oscillated $\nu_\mu \ (\bar{\nu}_\mu)$ and beam $\nu_e \ (\bar{\nu}_e)$ event spectrum. The Far Detector, located in Ash River, MN, USA, is 809 km from the ND and records the oscillated $\nu_e \ (\bar{\nu}_e)$ and the un-oscillated $\nu_\mu \ (\bar{\nu}_\mu)$ event spectrum. NOvA uses a data-driven technique called extrapolation to predict the expected number of $\nu_\mu \ (\bar{\nu}_\mu)$ and $\nu_e \ (\bar{\nu}_e)$ events at the Far Detector using the Near Detector data. The use of data from a functionally equivalent Near Detector provides a powerful constraint on the systematic uncertainties in NOvA neutrino oscillation analyses. As NOvA continues to add data statistics, a robust constraint on systematics becomes more crucial for neutrino oscillation analysis. The details of the NOvA neutrino oscillation analysis framework and how it constrains dominant systematic uncertainties using the Near Detector data will be discussed in this poster.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Investigating Gadolinium-Lined Sodium-Iodide Neutron Detectors for Mobile Applications

For enhancing the effectiveness of nonproliferation efforts in neutron detection, most portable instruments rely on 6 Li scintillators, 10 B-based detectors, or gas-filled 3 He proportional counters. Additionally, gamma-ray detectors based on scintillators and semiconductors are often employed for search applications to find radioactive material in the field. These systems typically include dedicated detectors along with separate high voltage supplies and processing electronics for the gamma-ray and neutron detectors. Ideally, a portable radiation detection system should be lightweight, compact, and cost-effective. In the field, scintillators can serve a dual purpose: (1) detecting gamma-rays and (2) detecting neutrons. Gamma-ray detection with scintillators is based on the interaction of gamma-rays within the scintillating material, whereas neutron detection depends indirectly on neutron capture events. These capture events generate conversion electrons and gamma-rays, which can interact with the scintillator. For enhancing neutron capture, the scintillator can be surrounded by neutron absorber materials with a high neutron cross section. The resulting secondary electrons and gamma-rays from neutron interactions, depending on the absorber material used, can then be analyzed to detect the presence of neutron sources. Similarly, semiconductor-based detectors can be employed along with neutron absorbers as liners for neutron detection. 158 Gd has a significantly larger neutron cross section than 3 He, commonly used in gas-filled proportional counters, as shown in Figure 1. For thermal (0.025 eV) neutrons, the absorption cross section of 158 Gd is 10,000 times greater than that of 3 He (refer to Figure 1). This feature makes naturally occurring gadolinium, which consists of 24.8% 158 Gd, a promising neutron absorber material for use in combination with gamma-ray detectors–yielding a hybrid detector–for neutron detection.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2025

The SAND detector for the DUNE experiment

The Deep Underground Neutrino Experiment (DUNE) is a next-generation project aiming to study several neutrino properties. It will feature two experimental setups: a near detector that will be installed at Fermilab, in proximity of the neutrino-production point, and a far detector at a distance of 1300 km and 1500 m underground, at the SURF laboratory. The DUNE design and configuration will allow the study of neutrino oscillation, astrophysical neutrinos, and beyond standard model physics. The near detector complex foresees three detectors to be installed. Among these, the System for on-Axis Neutrino Detection (SAND) will serve as on-axis beam monitor, reduce the systematic uncertainties for the oscillation analysis, and search for physics beyond the standard model. SAND will be composed of three sub-detectors, surrounded by a 0.6 T superconducting magnet. The outermost detector will be a lead/scintillating-fiber electromagnetic calorimeter while the inner volume will include a 1-ton liquid argon active target placed upstream followed by a target tracker system. The SAND detector and its goals will be shown in this poster.

Alemanno, Francesca [Salento U.; INFN, Lecce]↗
DOE OSTI2026

Track Matching in the DUNE Near Detectors

The Deep Underground Neutrino Experiment (DUNE) is an international particle physics experiment looking answer some of the largest unanswered questions in neutrino physics. DUNE uses a high power neutrino beam produced at Fermi National Accelerator Laboratory (Fermilab), and consists of a near detector (ND) also located at Fermilab and a far detector (FD) 1300 km away at the Sanford Underground Research Facility (SURF) in South Dakota. In the first phase of the experiment, the ND complex will contain a modular liquid argon TPC (ND-LAr) and a solid scintillator-based muon spectrometer (TMS), in addition to a beam monitoring detector (SAND) and systems for moving ND-LAr and TMS away from the neutrino beam axis (PRISM). A prototype of ND-LAr, the 2x2 demonstrator, alongside a solid scintillator muon tagger provided by repurposed MINERvA planes, has been built and taken data at Fermilab. For analyses with the ND, connecting particle tracks (such as muons) that exit the liquid argon active volume into the solid scintillator muon detector can improve particle identification and energy reconstruction, and alleviate pileup due to the intense beam. To match tracks between detectors during reconstruction, we have explored using Graph Neural Networks (GNNs) to connect tracks segments between the liquid argon detector region and the solid scintillator detector planes. We have trained a GNN on reconstructed simulated data from the 2×2 demonstrator and repurposed MINERvA planes. We will evaluate its performance and then train a similar network on reconstructed ND-LAr and TMS simulations.

Xing, Daniel [U. Colorado, Boulder]↗
DOE OSTI2025

μRWELL detector developments at Jefferson Lab for high luminosity experiments

One of the future plans at Jefferson Lab is running electron scattering experiments with large acceptance detectors at luminosities > 10^37 cm^−2 s^−1. These experiments allow the measurements of the Double Deeply Virtual Compton Scattering (DDVCS) reaction, an important physics process in the formalism of Generalized Parton Distributions, which has never been measured because of its small cross-section. The luminosity upgrade of CLAS12 or the SOLID detector makes Jefferson Lab a unique place to measure DDVCS. One of the important components of these high luminosity detectors is a tracking system that can withstand high rates of ≈ 1MHz/cm2. The recently developed Micro-Resistive Well (𝜇RWELL) detector technology is a promising option for such a tracking detector by combining good position resolutions, low material budget with simple mechanical construction, and low production costs. In this proceeding, we will discuss recent developments and studies with 𝜇RWELL detectors at Jefferson Lab for future upgrades of the CLAS12 detector to study the DDVCS reaction.

Hauenstein, Florian↗
DOE OSTI2025

Conceptual Design Report for the MATHUSLA Long-Lived Particle Detector near CMS

We present the Conceptual Design Report (CDR) for the MATHUSLA (MAssive Timing Hodoscope for Ultra-Stable neutraL pArticles) long-lived particle detector at the HL-LHC, covering the design, fabrication and installation at CERN Point 5. MATHUSLA is a 40 m-scale detector with an air-filled decay volume that is instrumented with scintillator tracking detectors, to be located near CMS. Its large size, close proximity to the CMS interaction point and about 100 m of rock shielding from HL-LHC backgrounds allows it to detect LLP production rates and lifetimes that are one to two orders of magnitude beyond the ultimate sensitivity of the HL-LHC main detectors for many highly motivated LLP signals. Data taking is projected to commence with the start of HL-LHC operations. We present a new 40m design for the detector: its individual scintillator bars and wavelength-shifting fibers, their organization into tracking layers, tracking modules, tower modules and the veto detector; define a high-level design for the supporting electronics, DAQ and trigger system, including supplying a hardware trigger signal to CMS to record the LLP production event; outline computing systems, civil engineering and safety considerations; and present preliminary cost estimates and timelines for the project. We also conduct detailed simulation studies of the important cosmic ray and HL-LHC muon backgrounds, implementing full track/vertex reconstruction and background rejection, to ultimately demonstrate high signal efficiency and $\ll 1$ background event in realistic LLP searches for the main physics targets at MATHUSLA. This sensitivity is robust with respect to detector design or background simulation details. Appendices provide various supplemental information.

Aitken, Branden [Victoria U.]↗
DOE OSTI2025

Diffractive Physics Program at the Electron–Ion Collider’s (EIC) 2 nd Detector

The Electron–Ion Collider (EIC) will be a novel experimental facility to explore the properties of gluons in nucleons and nuclei, shedding light on their structure and dynamics. The EIC community outlined the physics program of the EIC in a White Paper, and the demanding detector re quirements and potential technologies to deploy at an EIC detector were published in a comprehensive Yellow Report. The general-purpose detector resulting from these efforts, ePIC, is designed to perform a broad physics program. At the same time, the wider EIC community is strongly in favor of a second detector at the EIC. Having two general-purpose collider detec tors to support the EIC science program allows us to have cross-checks and control of systematic uncertainties for potential scientific discoveries. The second detector should feature complementary technologies where possible. It can also focus on specific measurements that are less well-addressed by ePIC. The second interaction region provides potentially improved forward detector acceptance at low pT and a secondary beam focus that enables to enhance the exclusive, tagging, and diffractive physics program. Hereby, I will present the potential capabilities of the second detector and discuss studies related to its diffractive physics program.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1972

Radiation damage effects by electrons, protons, and neutrons in Si/Li/ detectors.

The degradation in performance of lithium-compensated silicon nuclear particle detectors induced by irradiation at room temperature with 0.6-MeV and 1.5-MeV electrons, 1.9-MeV protons, and fast neutrons from a plutonium-beryllium source has been investigated. With increasing fluence, the irradiations produced an increase of detector leakage current, noise, capacitance, and a degradation in the performance of the detector as a charged-particle energy spectrometer. Following the irradiations, annealing effects were observed when the detectors were reverse-biased at their recommended operating voltages. Upon removal of bias, a continuous degradation of detector performance characteristics occurred. Detectors which had been damaged by electrons and protons exhibited a stabilization in their characteristics within two weeks after irradiation, whereas detectors damaged by neutrons had a continuous degradation of performance over a period of several months.

Liu, Y. M.↗
NASA NTRS1981

Multianode microchannel array detectors for Space Shuttle imaging applications

The Multi-Anode Microchannel Arrays (MAMAs) are a family of photoelectric, photoncounting array detectors that have been developed and qualified specifically for use in space. MAMA detectors with formats as large as 256 x 1024 pixels are now in use or under construction for a variety of imaging and tracking applications. These photo-emissive detectors can be operated in a windowless configuration at extreme ultraviolet and soft X-ray wavelengths or in a sealed configuration at ultraviolet and visible wavelengths. The construction and modes-of-operation of the MAMA detectors are briefly described and the scientific objectives of a number of sounding rocket and Space Shuttle instruments utilizing these detectors are outlined. Performance characteristics of the MAMA detectors that are of fundamental importance for operation in the Space Shuttle environment are described and compared with those of the photo-conductive array detectors such as the CCDs and CIDs.

Timothy, J. G.↗
NASA NTRS1984

Infrared and visible detector electronics for the Infrared Astronomical Satellite (IRAS)

The paper describes the detectors, preamplifiers, and processing electronics; the system characterization test methods and results; and the performance of the detectors and electronics during the first month of on-orbit operation of the IRAS telescope. The Focal Plane Array (FPA) consists of 62 IR channels and 8 visible channels operating at 2.5 K. The IR detectors are grouped in eight 7 or 8 channel staggered linear subarrays with shared bias voltage; the visible detectors are grouped in two 4 channel skewed arrays, also with shared bias. Each channel detector is dc coupled to a TIA preamplifier through a very low power thermally isolated JFET source follower operating at about 65 K within the FPA housing. The visible channel detectors are ac coupled to TIA preamplifiers and signal chain electronics using MOSFET source followers operating at about 2.5 K within the FPA housing. The detectors, preamplifiers, analog electronics, and grounding are discussed as they evolved and were implemented during FPA retrofit, telescope integration, and preparation for launch.

Langford, D. L.↗
NASA NTRS1990

Novel Si(1-x)Ge(x)/Si heterojunction internal photoemission long wavelength infrared detectors

There is a major need for long-wavelength-infrared (LWIR) detector arrays in the range of 8 to 16 microns which operate with close-cycle cryocoolers above 65 K. In addition, it would be very attractive to have Si-based infrared (IR) detectors that can be easily integrated with Si readout circuitry and have good pixel-to-pixel uniformity, which is critical for focal plane array (FPA) applications. Here, researchers report a novel Si(1-x)Ge(x)/Si heterojunction internal photoemission (HIP) detector approach with a tailorable long wavelength infrared cutoff wavelength, based on internal photoemission over the Si(1-x)Ge(x)/Si heterojunction. The HIP detectors were grown by molecular beam epitaxy (MBE), which allows one to optimize the device structure with precise control of doping profiles, layer thickness and composition. The feasibility of a novel Si(1-x)Ge(x)/Si HIP detector has been demonstrated with tailorable cutoff wavelength in the LWIR region. Photoresponse at wavelengths 2 to 10 microns are obtained with quantum efficiency (QE) above approx. 1 percent in these non-optimized device structures. It should be possible to significantly improve the QE of the HIP detectors by optimizing the thickness, composition, and doping concentration of the Si(1-x)Ge(x) layers and by configuring the detector for maximum absorption such as the use of a cavity structure. With optimization of the QE and by matching the barrier energy to the desired wavelength cutoff to minimize the thermionic current, researchers predict near background limited performance in the LWIR region with operating temperatures above 65K. Finally, with mature Si processing, the relatively simple device structure offers potential for low-cost producible arrays with excellent uniformity.

Lin, T. L.↗
NASA NTRS1992

Effect of space exposure of pyroelectric infrared detectors

Pyroelectric detectors are one of many different types of infrared radiation detectors. The pyroelectric detectors are of interest for long term space use because they do not require cooling during operation. Also, they can detect at very long wavelengths and they have a relatively flat spectral response. A disadvantage is that the radiation must be chopped in order to be detected by a pyroelectric detector. The objective was to determine the effects of launch and space exposure on the performance of commercially available pyroelectric detectors. The approach was to measure certain detector parameters before and after flight and try to determine the amount and cause of the degradation. The experiment was passive: no data was taken during flight. It is concluded that lithium-tantalate and strontium-barium-niobate are suitable materials for pyroelectric detectors for long term space applications.

Robertson, James B.↗
NASA NTRS1992

Effect of space exposure on pyroelectric infrared detectors

Pyroelectric detectors are one of the many different types of infrared radiation detectors. Pyroelectric detectors are of interest for long-term space use because they do not require cooling during operation. Also, they can detect at very long wavelengths and they have a relatively flat spectral response. A disadvantage is that the radiation must be chopped in order to be detected by a pyroelectric detector. The objective of the experiment was to determine the effects of launch and space exposure on the performance of commercially available pyroelectric detectors. The approach was to measure performance parameters of the detectors before and after flight on the Long-Duration Exposure Facility (LDEF) and determine the loss of detector performance. The experiment was passive; no data was taken during flight.

Robertson, James B.↗
NASA NTRS1993

Performance of high resolution decoding with Multi-Anode Microchannel Array detectors

The Multi-Anode Microchannel Array (MAMA) is a microchannel plate based photon counting detector with applications in ground-based and space-based astronomy. The detector electronics decode the position of each photon event, and the decoding algorithm that associates a given event with the appropriate pixel is determined by the geometry of the anode array. The standard MAMA detector has a spatial resolution set by the anode array of 25 microns, but the MCP pore resolution exceeds this. The performance of a new algorithm that halves the pixel spacing and improves the pixel spatial resolution is described. The new algorithm does not degrade the pulse-pair resolution of the detector and does not require any modifications to the detector tube. Measurements of the detector's response demonstrate that high resolution decoding yields a 60 percent enhancement in spatial resolution. Measurements of the performance of the high resolution algorithm with a 14 micron MAMA detector are also described. The parameters that control high resolution performance are discussed. Results of the application of high resolution decoding to speckle interferometry are presented.

Kasle, David B.↗
NASA NTRS2001

Development of Low-Noise High Value Chromium Silicide Resistors for Cryogenic Detector Applications

Extremely high sensitivity detectors, such as silicon bolometers are required in many NASA missions for detection of photons from the x-ray to the far infrared regions. Typically, these detectors are cooled to well below the liquid helium (LHe) temperature (4.2 K) to achieve the maximum detection performance. As photoconductors, they are generally operated with a load resistor and a pre-set bias voltage, which is then coupled to the input gate of a source-follower Field Effect Transistor (FET) circuit. It is imperative that the detector system signal to noise performance be limited by the noise of the detector and not by the noise of the external components. The load resistor value is selected to optimize the detector performance. These two criteria tend to be contradictory in that these detectors require load resistors in the hundreds of megaohms, which leads to a higher Johnson noise. Additionally, the physical size of the resistor must be small for device integration as required by such missions as the NASA High Resolution Airborne Wide-Band Camera (HAWC) instrument and the Submillimeter High Angular Resolution Camera (SHARC) for the Caltech Submillimeter Observatory (CSO). We have designed, fabricated and characterized thin film resistors using a CrSi/TiW/Al metal system on optical quality quartz substrates. The resistor values range from 100 megaohms to over 650 megaohms and are Johnson noise limited at LHe temperatures. The resistor film is sputtered with a sheet resistance ranging from 300 ohms to 1600 ohms and the processing sequence developed for these devices allows for chemically fine tuning the sheet resistance in-situ. The wafer fabrication process was of sufficiently high yield (>80%) providing clusters of good resistors for integrated multiple detector channels, a very important feature in the assembly of these two instruments.

Jhabvala, Murzy↗