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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Identification and reconstruction of low-energy electrons in the ProtoDUNE-SP detector

Measurements of electrons from 𝜈𝑒 interactions are crucial for the Deep Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as searches for physics beyond the standard model, supernova neutrino detection, and solar neutrino measurements. This article describes the selection and reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector. ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and operated at CERN as a charged particle test beam experiment. A sample of low-energy electrons produced by the decay of cosmic muons is selected with a purity of 95%. This sample is used to calibrate the low-energy electron energy scale with two techniques. An electron energy calibration based on a cosmic ray muon sample uses calibration constants derived from measured and simulated cosmic ray muon events. Another calibration technique makes use of the theoretically well-understood Michel electron energy spectrum to convert reconstructed charge to electron energy. In addition, the effects of detector response to low-energy electron energy scale and its resolution including readout electronics threshold effects are quantified. Finally, the relation between the theoretical and reconstructed low-energy electron energy spectra is derived, and the energy resolution is characterized. The low-energy electron selection presented here accounts for about 75% of the total electron deposited energy. After the addition of lost energy using a Monte Carlo simulation, the energy resolution improves from about 40% to 25% at 50 MeV. These results are used to validate the expected capabilities of the DUNE far detector to reconstruct low-energy electrons.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

J/Psi Photoproduction Near Threshold With CLAS12

The structure of the proton is comprised of quarks and a sea of gluons. A mechanism that can extract the characteristics of the hidden-color correlations of the nuclear wavefunction is the production of charm near threshold. Due to the fact that momentum transfer is large near threshold in the production of J/ψ , all three valence quarks must act coherently to ex- change energy for the reaction to occur. Models have been developed to predict the nature of J/ψ photoproduction at these specific energies. These include production mechanisms with the two-gluon and three-gluon exchanges. The transferred momentum dependence of the differential cross sections are sensitive to the gluonic form factors, which describe the distribution of color charge in the proton. The CLAS12 detector is capable of measuring J/ψ photoproduction at the energy range close to the threshold. Work showcased in this dissertation encompasses the preparation of the CLAS12 experiments, including the optimization of tracking reconstruction through the study of the Torus magnetic field. In terms of software, contributions were made to the CLAS12 Event Builder, a key stage of reconstruction where event-by-event information is summarized for efficient data analysis. After the run periods were successfully completed, analysis of the RG-A data commenced and an analysis framework was developed to measure the differential and total cross sections of J/ψ photoproduction in Hall B.

Newton, Joseph↗
DOE OSTI2013

Application of the BINS superheated drop detector spectrometer to the {sup 9}Be(p,xn) neutron energy spectrum determination

In the framework of TRASCO-BNCT project, a Bubble Interactive Neutron Spectrometer (BINS) device was applied to the characterization of the angle-and energy-differential neutron spectra generated by the {sup 9}Be(p,xn)reaction. The BINS spectrometer uses two superheated emulsion detectors, sequentially operated at different temperatures and thus provides a series of six sharp threshold responses, covering the 0.1-10 MeV neutron energy range. Spectrum unfolding of the data was performed by means of MAXED code. The obtained angle, energy-differential spectra were compared with those measured with a Bonner sphere spectrometer, a silicon telescope spectrometer and literature data.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

Theory and measurement of plasmonic terahertz detector response to large signals

Electron gas in the conduction channel of a Field Effect Transistor (FET) can support collective plasma oscillations tunable by the gate voltage. In the Dyakonov-Shur terahertz (THz) detector, nonlinearities in the plasma wave propagation in the gated channel of a FET lead to a constant source-to-drain voltage providing the detector output. We present the detector theory in the frame of the hydrodynamic model using the electron plasma Navier-Stokes and thermal transport equations, thus fully accounting for the hydrodynamic non-linearity, the viscosity, and pressure gradients in the detector response. Both resonant and broadband operations of the high electron mobility transistor (HEMT) based plasmonic detectors are described by this model. The relation between the electron channel density and gate voltage was modeled by the unified charge control model applicable both above and below the threshold voltage. The theoretical results are compared with the response measured in the short channel InGaAs HEMT and the analytical approximation. The THz source was operating at 1.63 THz, and the response was measured at varying signal intensities. The response of the detector operated in the open drain mode was measured above and below the threshold, and the theoretical and experimental results are shown to be in good agreement.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Augmented signal processing in Liquid Argon Time Projection Chambers with a deep neural network

The Liquid Argon Time Projection Chamber (LArTPC) is an advanced neutrino detector technology widely used in recent and upcoming accelerator neutrino experiments. It features a low energy threshold and high spatial resolution that allow for comprehensive reconstruction of event topologies. In current-generation LArTPCs, the recorded data consist of digitized waveforms on wires produced by induced signal on wires of drifting ionization electrons, which can also be viewed as two-dimensional (2D) (time versus wire) projection images of charged-particle trajectories. For such an imaging detector, one critical step is the signal processing that reconstructs the original charge projections from the recorded 2D images. For the first time, we introduce a deep neural network in LArTPC signal processing to improve the signal region of interest detection. By combining domain knowledge (e.g., matching information from multiple wire planes) and deep learning, this method shows significant improvements over traditional methods. This work details the method, software tools, and performance evaluated with realistic detector simulations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Spontaneous generation of athermal phonon bursts within bulk silicon causing excess noise, low energy background events, and quasiparticle poisoning in superconducting sensors

Solid state phonon detectors used in the search for dark matter and coherent neutrino nucleus interactions (CE $v$ NS) require excellent energy resolution (eV-scale or below) and low backgrounds. An unknown source of phonon bursts, the low energy excess (LEE), dominates other above-threshold backgrounds and generates excess shot noise from subthreshold bursts. Here, in this paper, we measure these phonon bursts for 12 days after cooldown in two nearly identical 1 cm 2 silicon detectors that differ only in the thickness of their substrate (1 vs 4 mm thick). We find that both the channel-correlated shot noise and near-threshold shared LEE relax with time since cooldown. Additionally, both the correlated shot noise and LEE rates scale linearly with substrate thickness. When combined with previous measurements of other silicon phonon detectors with different substrate geometries and mechanical support strategies, these measurements strongly suggest that the dominant source of both above and below threshold LEE is the bulk substrate. By monitoring the relation between bias power and excess phonon shot noise, we estimate that the energy scale for subthreshold noise events is 0.68 ± 0.38 meV. In our final dataset, we report a world-leading energy resolution of 258.5 ± 0.4 meV in the 1 mm thick detector. Simple calculations suggest that these silicon substrate phonon bursts are likely a significant source of quasiparticle poisoning in superconducting qubits operated in well shielded and vibration free environments.

Chang, C. L. [Argonne National Laboratory 1 , 9700↗
DOE OSTI2016

Xenon bubble chambers for direct dark matter detection

The search for dark matter is one of today's most exciting fields. As bigger detectors are being built to increase their sensitivity, background reduction is an ever more challenging issue. To this end, a new type of dark matter detector is proposed, a xenon bubble chamber, which would combine the strengths of liquid xenon TPCs, namely event by event energy resolution, with those of a bubble chamber, namely insensitivity to electronic recoils. In addition, it would be the first time ever that a dark matter detector is active on all three detection channels, ionization and scintillation characteristic of xenon detectors, and heat through bubble formation in superheated fluids. Preliminary simulations show that, depending on threshold, a discrimination of 99.99% to 99.9999+% can be achieved, which is on par or better than many current experiments. Furthermore, a prototype is being built at the University at Albany, SUNY. The prototype is currently undergoing seals, thermal, and compression testing.

Dark Matter detectors↗
DOE OSTI2020

Design and performance of the first IceAct demonstrator at the South Pole

Here in this paper we describe the first results of IceAct, a compact imaging air-Cherenkov telescope operating in coincidence with the IceCube Neutrino Observatory (IceCube) at the geographic South Pole. An array of IceAct telescopes (referred to as the IceAct project) is under consideration as part of the IceCube-Gen2 extension to IceCube. Surface detectors in general will be a powerful tool in IceCube-Gen2 for distinguishing astrophysical neutrinos from the dominant backgrounds of cosmic-ray induced atmospheric muons and neutrinos: the IceTop array is already in place as part of IceCube, but has a high energy threshold. Although the duty cycle will be lower for the IceAct telescopes than the present IceTop tanks, the IceAct telescopes may prove to be more effective at lowering the detection threshold for air showers. Additionally, small imaging air-Cherenkov telescopes in combination with IceTop, the deep IceCube detector or other future detector systems might improve measurements of the composition of the cosmic ray energy spectrum. In this paper we present measurements of a first 7-pixel imaging air Cherenkov telescope demonstrator, proving the capability of this technology to measure air showers at the South Pole in coincidence with IceTop and the deep IceCube detector.

47 OTHER INSTRUMENTATION↗
NASA NTRS2007

Expected Performance of the GLAST Burst Monitor

The GLAST Burst Monitor (GBM) will enhance LAT observations of GRBs by extending the spectral coverage from the LAT threshold down to approx. 8 kev, and will provide a trigger for re-orienting the spacecraft to observe delayed emission from selected bursts outside the LAT field of view. GBM consists of twelve NaI scintillation detectors operating in the 8 kev to 1 MeV energy range and two BGO scintillation detectors operating in the 150 keV to 30 MeV energy range. Detector resolution, effective area, and angular response have been determined by calibrations. Analyses indicate that the on-board burst threshold will be approx. 0.7 photon/cm2/s and the on-board burst localization accuracy will typically be better than 8 degrees.

Meegan, Charles↗
DOE OSTI2015

Status of the DAMIC Direct Dark Matter Search Experiment

The DAMIC experiment uses fully depleted, high resistivity CCDs to search for dark matter particles. With an energy threshold $\sim$50 eV$_{ee}$, and excellent energy and spatial resolutions, the DAMIC CCDs are well-suited to identify and suppress radioactive backgrounds, having an unrivaled sensitivity to WIMPs with masses $<$6 GeV/$c^2$. Early results motivated the construction of a 100 g detector, DAMIC100, currently being installed at SNOLAB. This contribution discusses the installation progress, new calibration efforts near the threshold, a preliminary result with 2014 data, and the prospects for physics results after one year of data taking.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1991

High resolution, low energy avalanche photodiode X-ray detectors

Silicon avalanche photodiodes have been fabricated, and their performance as X-ray detectors has been measured. Photon sensitivity and energy resolution were measured as a function of size and operating parameters. Noise thresholds as low as 212 eV were obtained at room temperature, and backscatter X-ray fluorescence data were obtained for aluminum and other light elements. It is concluded that the results with the X-ray detector are extremely encouraging, and the performance is challenging the best available proportional counters. While not at the performance level of either cryogenic silicon or HgI2, these device operate at room temperature and can be reproduced in large numbers and with much larger areas than typically achieved with HgI2. In addition, they are rugged and appear to be indefinitely stable.

Farrell, R.↗
DOE OSTI2022

Characterization of the Superconducting Microwave Properties of Aluminum Manganese

A microwave kinetic inductance detector (MKID) is a superconducting pair breaking detector that offers a number of unique advantages for realizing large-format arrays of ultra-sensitive detectors, such as inherent multiplexibility and relative ease of fabrication. With the detection threshold being set by the Cooper pair binding energy, and correspondingly, the superconducting critical temperature (T c ), typically well-understood MKID materials such as aluminum (Al) present a lower limit on the operating frequency. Aluminum manganese (Al-Mn) is a promising candidate material for MKIDs because it can be fabricated with nearly identical processing as pure Al, but allows for control of the T c , with varying levels of Mn doping or post-deposition heat treatment. In this study, we present initial results from an early characterization of AlMn using a series of lumped-element superconducting microwave resonators, including measurements of T c , internal quality factor, and noise performance over a range of Mn doping.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Discovery of a photoresponse amplification mechanism in compensated PN junctions

We report the experimental evidence of uncovering a photoresponse amplification mechanism in heavily doped, partially compensated silicon p-n junctions under very low bias voltage. We show that the observed photocurrent gain occurs at a bias that is more than an order of magnitude below the threshold voltage for conventional impact ionization. Moreover, contrary to the case of avalanche detectors and p-i-n diodes, the amplified photoresponse is enhanced rather than suppressed with increasing temperature. These distinctive characteristics lead us to hypothesize that the inelastic scattering between energetic electrons (holes) and the ionized impurities in the depletion and charge neutral regions of the p-n junction in a cyclic manner plays a significant role in the amplification process. Such an internal signal amplification mechanism, which occurs at much lower bias than impact ionization and favors room temperature over cryogenic temperature, makes it promising for practical device applications.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Search for Dark Photons Produced in 13 TeV p p Collisions

Searches are performed for both promptlike and long-lived dark photons, A ', produced in proton-proton collisions at a center-of-mass energy of 13 TeV, using A ' → μ + μ - decays and a data sample corresponding to an integrated luminosity of 1.6 fb -1 collected with the LHCb detector. The promptlike A ' search covers the mass range from near the dimuon threshold up to 70 GeV, while the long-lived A; search is restricted to the low-mass region 214 < m ( A ') < 350 MeV. No evidence for a signal is found, and 90% confidence level exclusion limits are placed on the γ– A ' kinetic-mixing strength. The constraints placed on prompt like dark photons are the most stringent to date for the mass range 10.6 < m ( A ') < 70 GeV, and are comparable to the best existing limits for m ( A ') < 0.5 GeV. The search for long-lived dark photons is the first to achieve sensitivity using a displaced-vertex signature.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Effective ZDC cross section measurement during a dedicated STAR elastic scattering physics store in Run15

At RHIC the collision rate per IP is monitored by the Zero Degree Calorimeters (ZDC) during most runs. Neutral particles produced in the collisions in the forward direction are detected in the ZDC and the collision rate corresponds to the rate of mutual neutrons above a variable threshold and within a certain coincidence window. Due to potential changes in the detector setup, con guration and electronics the ZDCs are calibrated every year by the use of vernier scans. At the end of the RHIC pp run in 2015 a dedicated run for the STAR elastic scattering physics program (PP2PP) was scheduled during which a total of 3 vernier scans was performed within the same store. This note presents the data and summarizes the results, i.e. effective ZDC cross section and the associated systematic errors from those scans.

43 PARTICLE ACCELERATORS↗
NASA NTRS1974

Excitation of metastable argon and helium atoms by electron impact

Using a time-of-flight method, the excitation of argon and helium metastables by electron impact is investigated in the energy range from threshold to about 50 eV. The secondary-electron yields of the metastable detector used are reviewed in detail. The effect of metastable recoil is also discussed. Comparisons with data from other investigators are presented.

Borst, W. L.↗
NASA NTRS1977

No new limit on size distribution of gamma-ray bursts

It is argued that the results of Carter et al. (1976), who derived an upper limit to the balloon intensity of small gamma-ray bursts at about 100 below the extrapolated known size spectrum and therefore concluded that the gamma-ray bursts are of galactic origin, are entirely consistent with the -1.5 index power-law extrapolation, so that no conclusion regarding the origin of gamma-ray bursts can be drawn. A reply of Carter et al. is published. Points at issue include: (1) whether a selection criterion of three successive 0.6-sec increases in the gamma-ray count rate ignores a significant or only a small number of events, (2) whether the spectra of all bursts extend below 100 keV, the satellite energy threshold, and (3) the required correction for the distortion of a horizontal, flat detector.

Cline, T. L.↗
DOE OSTI2019

High count rate thermal neutron detectors and electronics

Improved, high count rate thermal neutron counters and electronics enabling new, higher measurement capabilities are disclosed. Next generation 3He and 10B tubes may include an electronics package capable of operating at higher count rates and in higher gamma fields and providing more efficient use of 3He gas. Conventional detector systems may also be upgraded, providing a possible solution to measure spent nuclear fuel with high neutron efficiency previously not possible in 235U fission counter systems. Switching the number of tubes per amplifier allows use of the measured nuclear material for a calibration standard for dead time correction, increasing accuracy of neutron measurements systems. An optimized detector geometry and advanced electronics with double pulse filtering and a dual channel readout may be provided. A bipolar shaper may improve dead time, provide efficient detector use, reduce double pulsing, facilitate high count rate measurements, and allow remote threshold setting.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗