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At least 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

RD53A: A large-scale prototype chip for the phase II upgrade in the serially powered HL-LHC pixel detectors

The phase II upgrade of the HL-LHC experiments within the LHC intends to deepen the studies of the Higgs boson and to allow the discovery of further particles by adding an integrated luminosity of about 4000 fb -1 over 10 years of operation. This upgrade would overwhelm the installed pixel detector readout chips with higher hit rates and radiation levels than ever before. To match these extreme requirements the RD53 collaboration, a joint effort between ATLAS and CMS, developed RD53A, a new generation pixel detector readout chip prototype manufactured in a 65 nm CMOS technology. It is half the size of the final pixel chips and designed to meet requirements in the face of 3 GHz/cm 2 hit rate after irradiation to 500 Mrad. The detector is able to use 50×50 μm 2 or 25×100 μm 2 pixels with high readout speed of up to 4 links per chip with 1.28 Gbit/s each. Shunt–LDO regulators integrated on the bottom of the chip provide the required voltages to the two power domains, analog and digital. These regulators enable serial powering of the pixel modules, which is the only feasible, radiation hard scheme to ensure acceptable power cable losses and to stay within the material budget for the future pixel detectors. Finally, an overview of the status and challenges of serial powering and the Shunt–LDO regulator development will be given.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

AEDAM: Whole Program Adaptive Error Detection and Mitigation (Final Report)

The overall goals of the AEDAM project were to fundamentally transform software transient-error detection through the design of configurable specialized detectors, quantitative characterization of hardware resilience and software vulnerabilities, and composition of the specialized detectors to most efficiently protect the whole program. Within this scope, UT Austin's research contribution related to enabling and studying the composition of detectors and possible different hardware errors, specifically: (1) developed the Hamartia open-source error injection framework that is designed to make composition studies simple, and (2) develop the methodology and demonstrate the potential benefits of error detector composition.

97 MATHEMATICS AND COMPUTING↗
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↗
NASA NTRS2000

A Recommended Procedure for Estimating the Cosmic Ray Spectral Parameter of a Simple Power Law

A simple power law model consisting of a single spectral index a(f(sub i)) is believed to be an adequate description of the galactic cosmic ray (GQ proton flux at energies below 1013 eV. Two procedures for estimating a(f(sub i)), referred as (1) the method of moments, and (2) maximum likelihood, are developed and their statistical performance compared. I concluded that the maximum likelihood procedure attains the most desirable statistical properties and is hence the recommended statistic estimation procedure for estimating a1. The maximum likelihood procedure is then generalized for application to a set of real cosmic ray data and thereby makes this approach applicable to existing cosmic ray data sets. Several other important results, such as the relationship between collecting power and detector energy resolution, as well as inclusion of a non-Gaussian detector response function, are presented. These results have many practical benefits in the design phase of a cosmic ray detector because they permit instrument developers to make important trade studies in design parameters as a function of one of the science objectives, which is particularly important for space-based detectors where physical parameters, such as dimension and weight, impose practical limits to the design envelope.

Howell, Leonard W.↗
DOE OSTI2023

A novel integrated time-resolved array avalanche photodiode detection system for nuclear resonant scattering measurements

Here, the nuclear resonant scattering (NRS) experiment requires photon-counting detectors with high time resolution, short dead time, large dynamic range, low noise, and large detection area. An 8-channel avalanche photodiode (APD) array detector system with high integrity, flexibility, and reliability has been developed to adapt to the demands of NRS experiments. The detector system mainly consists of four key parts: (i) an array-APD sensor, (ii) 8-channel integrated fast preamplifiers, (iii) the time-to-digital converter readout electronics, and (iv) a data acquisition system and EPICS support software. Remarkably, the system exhibits a time resolution of better than 500 ps and has a sufficiently low noise level, allowing for the lowest detection energy threshold of 4 keV. The performance of the new array-APD system as well as its real application in nuclear forward scattering (NFS) and nuclear resonant inelastic x-ray scattering (NRIXS) experiments was tested in two synchrotron facilities. With the new system, the NFS signal very close to the prompt electronic scattering signal can be extracted. Thanks to the customized EPICS-areaDetector-based control software, NRIXS spectra can be readily measured with time and energy information of the NRIXS signal stored in the raw data, which is promising for developing NRIXS data analysis in the time domain. The array-APD detector can be deployed for nuclear resonant scattering experiments at various synchrotron radiation facilities.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Performance of a ton-scale water-based liquid scintillator detector

This study reports the performance and light yield of 1% concentration water-based liquid scintillator (WbLS) deployed in a 1000-liter detector. A light yield of 99± 15 photons per MeV is determined by comparing data with simulation. This result aligns with our previous light yield determination using smaller detectors, thus establishing a solid foundation for the ongoing development and deployment of WbLS in larger-scale detectors. In conclusion, the feasibility of in situ preparation and the stability of light yield in WbLS are demonstrated, reinforcing its suitability for long-term experimental endeavors.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1984

Miniature triaxial metastable ionization detector for gas chromatographic trace analysis of extraterrestrial volatiles

The present investigation is concerned with a miniature metastable ionization detector featuring an unconventional electrode configuration, whose performance characteristics parallel those of traditional design. The ionization detector is to be incorporated in a flight gas chromatograph (GC) for use in the Space Shuttle. The design of the detector is discussed, taking into account studies which verified the sensitivity of the detector. The triaxial design of the detector is compared with a flat-plate style. The obtained results show that the principal goal of developing a miniature, highly sensitive ionization detector for flight applications was achieved. Improved fabrication techniques will utilize glass-to-metal seals and brazing procedures.

Woeller, F. H.↗
NASA NTRS2005

III-V Compound Detectors for CO2 DIAL Measurements

Profiling of atmospheric carbon dioxide (CO2) is important for understanding the natural carbon cycle on Earth and its influence on global warming and climate change. Differential absorption lidar is a powerful remote sensing technique used for profiling and monitoring atmospheric constituents. Recently there has been an interest to apply this technique, at the 2 m wavelength, for investigating atmospheric CO2. This drives the need for high quality detectors at this wavelength. Although 2 m detectors are commercially available, the quest for a better detector is still on. The detector performance, regarding quantum efficiency, gain and associated noise, affects the DIAL signal-to-noise ratio and background signal, thereby influencing the instrument sensitivity and dynamic range. Detectors based on the III-V based compound materials shows a strong potential for such application. In this paper the detector requirements for a long range CO2 DIAL profiles will be discussed. These requirements were compared to newly developed III-V compound infrared detectors. The performance of ternary InGaSb pn junction devices will be presented using different substrates, as well as quaternary InGaAsSb npn structure. The performance study was based on experimental characterization of the devices dark current, spectral response, gain and noise. The final results are compared to the current state-of-the-art InGaAs technology. Npn phototransistor structure showed the best performance, regarding the internal gain and therefore the device signal-to-noise ratio. 2-micrometers detectivity as high as 3.9 x 10(exp 11) cmHz(sup 1/2)/W was obtained at a temperature of -20 C and 4 V bias voltage. This corresponds to a responsivity of 2650 A/W with about 60% quantum efficiency.

Refaat, Tamer F.↗
DOE OSTI2023

DRiFT - Release 2.1.0: Organic Scintillators and Gas Detectors

DRiFT (a Detector Response Function Toolkit) is LANL-developed software that post-processes output from the extensively validated radiation transport code, MCNP, and generates realistic nuclear instrumentation response. DRiFT is designed to be flexible, enabling users to specify detector type and many experimental settings, as well as accommodating the addition of their own desired features. The focus of this release is on organic scintillator, gas detector, and associated capabilities, while semiconductor features are still under development. Organic scintillators are widely used in the areas of nuclear safeguards and nuclear non-proliferation efforts. DRiFT has several diagnostic and detector physics features relevant to detailed scintillator simulations including: tracking source particle information, scintillation light production, the effects of PMT quantum efficiency and gain, and digitizer settings. Users can select responses from many scintillator and PMT types supported natively by DRiFT, or add their own by following the instructions in this document. DRiFT also has several diagnostic and detector physics features relevant to neutron gas detector simulations including: gas detector wall effects, inactive areas at the end of detector tubes, and effects of a preamplifier. We acknowledge that DRiFT is under active development, bug reports and general questions and comments should be directed to Madison Andrews, madison@lanl.gov. This manual is divided into four parts: I) An overview of DRiFT, including how to obtain and install the executable, II) A description of the detector physics related to scintillators available, III) a description of more general DRiFT features the user may find useful, and IV) a description of the test suite and examples made available with the code release.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRSDate not supplied

Parallel plate capacitor TiN KID array development for the Balloon Experiment for Galactic Infrared Science

The Balloon Experiment for Galactic Infrared Science (BEGINS) will map dust spectral energy distributions (SEDs) between 25 and 250 microns near high-mass star regions, characterizing the radiation fields and dust properties of a variety of stellar environments. To accomplish these goals, BEGINS will be outfitted with roughly 1,800 titanium nitride (TiN), superconducting kinetic inductance detectors (KIDs). A parallel plate capacitor KID design is used to achieve high pixel density arrays. A cryogenic, silicon-based, metal-mesh linear variable filter will define detector band passes across the KID array. Optical coupling to the filters and telescope will be accomplished using silicon microlenses. Here we present laboratory characterization of prototype BEGINS detector arrays, describe future array development plans, and describe the testbed used to characterize the arrays.

Nicholas F. Cothard↗
NASA NTRS1989

Pulse shape discrimination for background rejection in germanium gamma-ray detectors

A pulse-shape discrimination (PSD) technique is developed to reject the beta-decay background resulting from activation of Ge gamma-ray detectors by cosmic-ray secondaries. These beta decays are a major source of background at 0.2-2 MeV energies in well shielded Ge detector systems. The technique exploits the difference between the detected current pulse shapes of single- and multiple-site energy depositions within the detector: beta decays are primarily single-site events, while photons at these energies typically Compton scatter before being photoelectrically absorbed to produce multiple-site events. Depending upon the amount of background due to sources other than beta decay, PSD can more than double the detector sensitivity.

Feffer, P. T.↗
NASA NTRS1979

Hydrogen chloride partitioning in a Titan III exhaust cloud diluted with ambient air

Measurements and analysis are presented of the partitioning of HCl between hydrochloric acid aerosol and gaseous HCl in a Titan III exhaust cloud, as the cloud is diluted with humid ambient air. Partitioning was determined by measuring the gaseous HCl concentration with a recently developed airborne Gas Filter Correlation detector and simultaneously with a chemiluminescence detector which measures total HCl. Although equilibrium predictions for HCl aerosol formation indicated that no HCl aerosol should exist in the exhaust cloud for the meteorological conditions of this launch, the measurements indicated significant HCl aerosol formation. These measurements will provide verification for advanced modeling programs now under development.

Sebacher, D. I.↗
NASA NTRS1992

Observations of winds with an incoherent lidar detector

A Fabry-Perot interferometer and image-plane detector system to be used as a receiver for a Doppler lidar have been developed. This system incorporates the latest technology in multichannel detectors, and it is an important step toward the development of operational wind profiler systems for the atmosphere. The instrumentation includes a stable high-resolution optically contacted plane etalon and a multiring anode detector to scan the image plane of the Fabry-Perot interferometer spatially. The high wavelength resolution provided by the interferometer permits the aerosol and molecular components of the backscattered signal to be distinguished, and the Doppler shift of either component can then be used to determine the wind altitude profile. The receiver performance has been tested by measuring the wind profile in the boundary layer. The Fabry-Perot interferometer and image-plane detector characteristics are described and sample measurements are presented. The potential of the system as a wind profiler in the troposphere, the stratosphere, and the mesosphere is also considered.

Abreu, Vincent J.↗
DOE OSTI2020

Development of Improved Noble Liquid Purity Measurements (Final Technical Report)

The main goal of the Detector R&D project supported by this grant, “Development of Improved Noble Liquid Purity Measurements”, was to perform a scoping study of the feasibility of trapping ions in a liquid argon medium using a radiofrequency (RF) quadrupole trap, and to subsequently use the population of trapped ions to make measurements of the properties of the liquid medium. Using RF quadrupole traps immersed in a noble liquid to trap ions may yield new capabilities to detect and quantify the presence of impurities, as well as enabling other measurements of the microphysics in a noble liquid environment. The major activities undertaken during this project include: the development of a simulation of ions in a liquid argon medium; the designing of a prototype RF quadrupole trap; and the setup of hardware to be used in testing the prototype in vacuum and gas conditions. The summary of these major activities is reported here.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

TexAT detector upgrade for 14 O($α$, $p$) 17 F cross section measurement

A direct cross-section measurement of the 14 O($α$, $p$) 17 F reaction is important to understand the light curves of x-ray bursts. The measurement will be performed using the Texas Active Target TPC version 2 (TexAT_v2). The TexAT_v2 aims at measuring lower energy protons from the reaction than the original TexAT. Newly developed silicon and CsI(Tl) detector arrays are added at the left, right and bottom of a modified field cage to increase its detection efficiency. Furthermore, this paper describes the overall specifications and two commissioning experiments performed at Texas A&M University.

14O(α, p)17F↗
NASA NTRS1990

Status of LWIR HgCdTe infrared detector technology

The performance requirements that today's advanced Long Wavelength Infrared (LWIR) focal plane arrays place on the HgCdTe photovoltaic detector array are summarized. The theoretical performance limits for intrinsic LWIR HgCdTe detectors are reviewed as functions of cutoff wavelength and operating temperature. The status of LWIR HgCdTe photovoltaic detectors is reviewed and compared to the focal plane array (FPA) requirements and to the theoretical limits. Emphasis is placed on recent data for two-layer HgCdTe PLE heterojunction photodiodes grown at Loral with cutoff wavelengths ranging between 10 and 19 microns at temperatures of 70 to 80 K. Development trends in LWIR HgCdTe detector technology are outlined, and conclusions are drawn about the ability for photovoltaic HgCdTe detector arrays to satisfy a wide variety of advanced FPA array applications.

Reine, M. B.↗
NASA NTRS1982

Multispectral Linear Array (MLA) science and technology program

A Goddard Space Flight Center program of science studies and technology development to provide the basis for future earth observation sensors employing multispectral linear array (MLA) technology is described. Establishment of MLA performance parameters and performance modeling make up the primary science activities. Critical technologies being developed include: short-wave infrared (SWIR) detector arrays, visible/and near infrared detector arrays, and passive cryogenic coolers. Supporting activities include: test and field instrument development, focal plane research and assessment laboratory, system simulation laboratory, calibration sources and techniques, optics, and thermal infrared arrays.

Barnes, W. L.↗
NASA NTRS1973

Metal-oxide-metal point contact junction detectors

The detection mechanism(s) and design of a mechanically stable metal-oxide-metal point contact junction detector are considered. A prototype for a mechanically stable device has been constructed and tested. A technique has been developed which accurately predicts microwave video detector and heterodyne mixer SIM (semiconductor-insulator-metal) diode performance from low dc frequency volt-ampere curves. The difference in contact potential between the two metals and geometrically induced rectification constitute the detection mechanisms.

Baird, J.↗