Detector Wall Research for Fast Gamma Signal Detection in Neutron-Diagnosed Subcritical Experiment Applications Project #: LAO-026-20 Year 3 of 3
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Baker, Stuart A↗
Engineering topics
Schwellenbach, David D
Publications and source records attributed to Schwellenbach, David D.
Nevada National Security Site, Multi-pulse Soft X-ray Source, Experimental Diagnostic Design Report
Milestone report produced for the NNSA, NA-113 Office of Experimental Science by the Advanced Diagnostics program in the NNSS Stockpile Experimentation and Operations group with the Radiography and Advanced Imaging Development project.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Gamma single-hit detector for NDSE
2021 annual project report for SDRD Program. Edited and approved by author. Will be made available on SDRD website in future. An associated abstract/summary for this longer report will be submitted to STIP as well.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Accelerated Beta Radiation Aging of Interlayer Titanium Nitride in Gallium Nitride Contacts
Research conducted under the Laboratory Directed Research and Development Program at Pacific Northwest National Laboratory, a multiprogram national laboratory operated by Battelle for the U.S. Department of Energy. An NNSS author co-authored this paper, and portions of this work were supported by the Mission Support and Test Services, LLC, under Contract No. DE-NA0003624 with the U.S. Department of Energy, National Nuclear Security Administration, NA-10 USDOE NA Office of Defense Programs (NA-10). PNNL-SA-163618 Currently, there is no good way to determine the influence of radiation on the aging of betavoltaic electrical contacts. This work tested a method to accelerate the aging of the contacts inside a betavoltaic by enhancing energy deposition within the interfacial region of interest. An electrical contact of gold-titanium on gallium nitride was aged by exposure to tritium betas and electrons in a beamline. The interface stoichiometry was compared to the electrical performance of the contact. The method to age the betavoltaic component could help predict the lifetime performance of the internal electrical contacts and provide assurance of deployment reliability.
36 MATERIALS SCIENCE↗
Comparison of Simulated and Experimentally Measured Detector Impulse Responses to Pulsed X-rays
The Gamma Array Simulation Toolkit (GAST) is a multi-physics software stack comprised of Geant4, MATLAB, and experimentally measured photomultiplier tube (PMT) impulse response waveforms that is used to model and inform the end-to-end performance of radiation detector systems. In order to validate the ability of GAST to predict the impulse response of a modeled detector configuration operated in current mode, experimental measurements using the Nevada National Security Site Transformational Diagnostics and Imaging 2 MeV endpoint energy electron linear accelerator (linac) with a tungsten target were performed. Seven different detector configurations consisting of unique combinations of scintillator material, size, reflectivity conditions, presence or absence of light guide, and PMT were evaluated. The resultant impulse response of each detector configuration was recorded and compared to a GAST simulation that emulated the respective linac experiment conditions. The comparison of the experimental and simulated detector impulse responses indicated that GAST can reliably predict detector impulse responses.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
X-Ray Phase Contrast Imaging for Dynamic Material Mix Experiments, LAO-003-17, Year 3 of 3
X-ray phase contrast imaging with transmission gratings for density profile measurements has been developed and tested for dynamic experimental applications. Talbot-Lau x-ray deflectometry is a new method of measuring x-ray refraction in addition to attenuation and ultrasmall-angle scattering that has recently been developed for static imaging, primarily for medical and industrial applications. To obtain density profiles from fast-evolving systems, we must use a flash x-ray source with a spot size much larger than the continuous microfocus sources of static imaging systems, and we can obtain only a single exposure. The challenges to measuring electron density profiles of two mixed elements from a single-image, low spatial resolution system are addressed, and initial results from the first dynamic experiments with one such system, conducted on a gas launcher at the end of FY 2018 and beginning of FY 2019, are presented. In FY 2019, we designed and built a new deflectometer designed for detonator experiments to test new techniques to improve the sensitivity and reliability of the diagnostic.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗