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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Characterization of Partial Charge Collection Induced by Neutron Damage in High-Purity Germanium Detectors

This paper investigates the correlation of damage induced by neutron interactions and degradation in the spectra of HPGe detectors. As neutrons kinetically interact with germanium crystals, they create interstitial and vacancy defects within the lattice. These defects then interfere with the charge migration of electron-hole pairs and reduce resolution in the observed energy spectrum. The partial charge collection produces observable spectral changes by increasing the peak width and reducing resolution (full width half maximum). A detailed characterization using various check sources was performed before and after iterations of neutron exposure in order to observe the effects of the neutron damage. An additional set of measurements was performed along with characterizations to show the detector’s response at discrete locations on the HPGe crystal. This was done to observe how the spectrum changes when the gamma rays are isolated to regions of various thicknesses of germanium. In order to impart damage, the detector was placed inside a californium shuffler with the face of the detector against the guide tube for the 252 Cf source. For irradiation of the HPGe, the source was then positioned in front of the face of the detector using the stepper motor of the shuffler. The neutron exposure time intervals were recorded and increased based on the initial damage observed. An MCNP simulation was performed to estimate the amount of interactions that occurred in the germanium crystal to ensure enough damage had occurred. Studying the effects that neutron damage imparts on a bullet-type HPGe detector can help provide necessary data to estimate total neutron exposure limits, reduce the likelihood of decisions made on suspect data, and aid in diagnostics of a damaged detector.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Extraction, Separation, and Production of High Purity Rare Earth Elements and Critical Minerals from Coal-Based and Related Resources

The general objectives of this project are to develop concepts for rare earth metal and critical mineral production from coal-based and related (minerals associated with coal) resources and incorporate them into a Technical Research Plan with an associated overall flow sheet. The project team has extensive expertise in market evaluation, mineral separation, leaching, chemical separations, alternative metallothermic reaction technology, electrowinning, and electrorefining that was critical to the success of the proposed project. The project included critical industrial partners needed for project success. The project team has extensive expertise in market evaluation, mineral separation, leaching, chemical separations, alternative reduction technology, electrowinning, and electrorefining as well as appropriate pilot-scale facilities to enable this project. The project encompassed broader opportunities for developing domestic resources of REE/CM materials for a more resilient, diverse, and secure supply chain for REE/CM materials with built-in redundancies and appropriate resource stockpiles. The production of REE/CM materials will help to revitalize and rebuild world-class American manufacturing capacity and the related workforce through new jobs and infrastructure. Furthermore, due to the nature and location of the production sites, economic growth in diverse communities of color and economically distressed areas will be cultivated. Finally, this technology can be applied to reuse and remediate coal waste tailings for REE/CM production.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2024

Trace Element Control in Master Alloys and Impact of Feedstock Purity on a Ta-containing Steel during Electroslag Remelting

Advanced materials design often leads to new complex compositions that can bring challenges to manufacturing processes. Melt processing of a novel alloy with a tight chemistry range revealed a 25% Ta loss after manufacturing. Vacuum induction melting (VIM) and electroslag remelting (ESR) were performed using industry practices at a laboratory scale and the loss occurred from the VIM electrode to the ESR ingot. Several tools were used for characterization, including combustion analysis, scanning electron microscopy, and electron probe microanalysis for observation of the precipitate and inclusion phases. Additionally, computational modeling of the ESR process was performed to predict macrosegregation and inclusion travel. It was found that a significant amount of Ta2O5 inclusions formed during VIM and were transferred to the slag during ESR. This led to a 95% decrease in density of inclusions explaining to Ta loss. Pathways to better control advanced alloy chemistries during melt processing will be discussed.

Detrois, Martin↗
DOE OSTI2026

Energy-Efficient Direct Air Capture System for High Purity CO 2 Separation

The primary objective of this project is to demonstrate the University of Cincinnati’s direct air capture (DAC) sorbent technology in a monolithic structure installed in a passive air contactor (PAC). The modified amine-based sorbent technology provides reduced heat of desorption and resistance to thermal and oxidative degradations for robust and long-term performances and cost effective sorbent management. During the project period, additional amine modifications were developed and a U.S./PCT patent application was filed.

42 ENGINEERING↗
DOE OSTI2025

High Purity Germanium Detector Normalization

The presentation summarizes a project completed by our group a couple years ago comparing two detectors and attempting to normalize the results using a mathematical equation and how those results impacted our current operations.

Drumm, Natalie Daphne [Sandia National Laboratorie↗
NASA NTRS1972

Electron beam chemistry produces high purity metals

Application of radiation chemistry for deposition of metals by irradiation of aqueous solutions with high energy electrons is presented. Design of reaction vessel for irradiation of solution is illustrated. Features of radiochemical technique and procedures followed are described.

Philipp, W. H.↗