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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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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Characterization of the hardened single line of sight camera at the National Ignition Facility

The hardened single line of sight camera has been recently characterized in preparation for its deployment on the National Ignition Facility. The latest creation based on the pulse-dilation technology leads to many new features and improvements over the previous-generation cameras to provide better quality measurements of inertial confinement fusion experiments, including during high neutron yield implosions. Here, we present the characterization data that illustrate the main performance features of this instrument, such as extended dynamic range and adjustable internal magnification, leading to improved spatial resolution.

Trosseille, C. (ORCID:0000000289430482)↗
DOE OSTI2020

Reflectivity and PDE of VUV4 Hamamatsu SiPMs in liquid xenon

Considering reflective properties of materials and photodetection efficiency (PDE) of photodetectors is important for optimizing energy resolution and sensitivity of the next generation neutrinoless double beta decay, direct detection dark matter, and neutrino oscillation experiments that will use noble liquid gases, such as nEXO, DARWIN, DarkSide-20k, and DUNE . Little information is currently available about reflectivity and PDE in liquid noble gases, because such measurements are difficult to conduct in a cryogenic environment and at short enough wavelengths. Here we report a measurement of specular reflectivity and relative PDE of Hamamatsu VUV4 silicon photomultipliers (SiPMs) with 50 μ m micro-cells conducted with xenon scintillation light ( ~ 175 nm) in liquid xenon. The specular reflectivity at 15 o incidence of three samples of VUV4 SiPMs is found to be 30.4 ± 1.4%, 28.6 ± 1.3%, and 28.0 ± 1.3%, respectively. The PDE at normal incidence differs by ± 8% (standard deviation) among the three devices. The angular dependence of the reflectivity and PDE was further measured for one of the SiPMs. Both the reflectivity and PDE decrease as the angle of incidence increases. This is the first measurement of an angular dependence of PDE and reflectivity of a SiPM in liquid xenon.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Reflectance of Silicon Photomultipliers at Vacuum Ultraviolet Wavelengths

Characterization of the vacuum ultraviolet (VUV) reflectance of silicon photomultipliers (SiPMs) is important for large-scale SiPM-based photodetector systems. In this work, we report the angular dependence of the specular reflectance in vacuum of SiPMs manufactured by Fondazionc Bruno Kessler (FBK) and Hamamatsu Photonics K.K. (HPK) over wavelengths ranging from 120 to 280 nm. Refractive index and extinction coefficient of the thin silicon-dioxide film deposited on the surface of the FBK SiPMs are derived from reflectance data of an FBK silicon wafer with the same deposited oxide film as SiPMs. The diffuse reflectance of SiPMs is also measured at 193 nm. We use the VUV spectral dependence of the optical constants to predict the reflectance of the FBK silicon wafer and FBK SiPMs in liquid xenon.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Radioisotope Science and Technology Division FY 2025 Core R&D Summary Report: Competitive Projects, Postdoctoral Researchers, and Student Interns

R&D efforts in support of the Oak Ridge National Laboratory (ORNL) Isotope Program Radioisotope Portfolio are led by the Radioisotope Science and Technology Division (RSTD). In addition to supporting the ORNL Isotope Program Radioisotope Portfolio, RSTD supports a portfolio of research related to fundamental properties of radioisotopes and radioisotope applications, including diagnostic and therapeutic uses of medical radioisotopes, radioisotopes for national security, and the production of 238 Pu for the National Aeronautics and Space Administration (NASA) and US Department of Energy (DOE) Office of Nuclear Energy. RSTD is organized into functional science and engineering groups, with most staff members supporting multiple programs. The goal of this organization is to enable synergy between programs such that R&D advances coming from other programs may provide benefit to the ORNL Isotope Program. R&D within RSTD is focused around addressing five grand challenges, as documented in the strategic plan for the DOE Office of Isotope R&D and Production, or DOE Isotope Program (IP), Radioisotope Production R&D activities at ORNL: 1. Maximizing the scientific output of radioisotope transmutation resources, 2. Maximizing the scientific output of radioisotope processing resources, 3. Minimizing waste and having optimal waste disposition, 4. Focusing on product quality and reliability, and 5. Expanding the use of beneficial isotopes. The ORNL Core R&D program, one of the primary R&D components within the ORNL Isotope Program Radioisotope Portfolio, ranges from benchtop to demonstration activities, with a focus on researching enhanced production techniques, developing emerging isotopes, and developing the talent pipeline for radioisotope science and technology. Projects within the Core R&D Program are led primarily by RSTD staff members. In supporting enhanced production techniques, the Core R&D program presents an opportunity to fund novel R&D that might not be tied to a specific radioisotope product but still presents a high potential for broad applicability in the longer term. In supporting the development of emerging isotopes, the Core R&D program develops high-priority isotopes that are not able to be fully supported through production funds.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2023

Recent Progress in Modulated Photothermal Radiometry

In this review, the emerging work using a technique known as modulated photothermal radiometry (MPTR) is evaluated. As MPTR has matured, the previous discussions on theory and modeling have become increasingly limited in their applicability to the current state of the art. After a brief history of the technique, the currently used thermodynamic theory is explained, highlighting the commonly applied simplifications. The validity of the simplifications is explored via modeling. Various experimental designs are compared, and the differences are explored. New applications, as well as emerging analysis techniques, are presented to emphasize the trajectory of MPTR.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Energy-Efficient Neuromorphic Architectures for Nuclear Radiation Detection Applications

A comprehensive analysis and simulation of two memristor-based neuromorphic architectures for nuclear radiation detection is presented. Both scalable architectures retrofit a locally competitive algorithm to solve overcomplete sparse approximation problems by harnessing memristor crossbar execution of vector–matrix multiplications. The proposed systems demonstrate excellent accuracy and throughput while consuming minimal energy for radionuclide detection. To ensure that the simulation results of our proposed hardware are realistic, the memristor parameters are chosen from our own fabricated memristor devices. Based on these results, we conclude that memristor-based computing is the preeminent technology for a radiation detection platform.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Women in Nuclear Security: The United Arab Emirates Story

Historically in the United Arab Emirates, security personnel stationed at nuclear sites were typically men with military or policing backgrounds. Although these groups bring important, transferrable skills and experience to the nuclear security mission, some Emirati stakeholders recognize the increased benefit of a greater diversity of voices and backgrounds within the nuclear security team hierarchy. By recruiting from a wider range of disciplines and encouraging gender diversity, the security team could develop broader insight into security challenges, and a greater variety of perspectives could bring forth more innovative solutions. When aligning a diverse, multinational workforce with a common mission, all members of a security organization must fundamentally change their individual approaches to the work; the entire staff must be on the same page. This can be particularly challenging for some people who find it difficult to transition from a framework of beliefs because of past experiences based on prescriptive, exclusionary, hierarchical thought. Also, national cultural values are learned early, held deeply, and change slowly over the course of generations, and inherent biases rooted in these values can create barriers to the collective progress of a team. Creating a more open, diverse, and transparent culture for the team by accepting a unique, egalitarian, professional nuclear security culture that all members adhere to can be a challenging task for some. In this article, I share my experiences related to professional roadblocks, personal challenges, and lessons learned, particularly those regarding the empowerment of women in science and engineering, while developing and establishing the United Arab Emirates nuclear security program. I also discuss the support (and underrepresentation) of women, including those currently in critical leadership positions, and their careers in nuclear security.

Barakah Nuclear Power Plant↗