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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Cosmic diffuse gamma rays from 2 to 25 MeV

Results are reported for measurements of cosmic diffuse gamma rays performed with a double Compton scatter gamma-ray telescope flows aboard a balloon at 3.5-g/sq cm residual atmosphere. The operation and calibration of the telescope are briefly reviewed, unwanted backgrounds are identified, and the only significant background for the telescope used is shown to arise from the interaction of albedo neutrons with hydrogen and carbon in one of the liquid scintillators. The fluxes of cosmic diffuse gamma rays with energies of 2 to 3, 3 to 5, 5 to 7, 7.5 to 10 MeV are listed, and upper limits are provided for energies of 10 to 15 and 15 to 25 MeV. These data are compared with numerous previous measurements, and no indication is found that the diffuse radiation is statistically different from isotropic. Upper limits are placed on the gamma-ray fluxes (mainly 3 to 25 MeV) from various localized sources.

White, R. S.↗
NASA NTRS1978

Evidence that cosmic gamma-ray bursts are galactic

Balloon observations registering scatter angles in a liquid scintillator have revealed gamma-ray bursts having energies as low as 10 to the -7th ergs per square cm. The burst distribution is graphed according to energy and frequency. The hypothesis that the bursts are galactic in origin is in good agreement with their small recorded energies and their predicted distribution on the graph.

White, R. S.↗
NASA NTRS1979

Atmospheric gamma ray angle and energy distributions from sea level to 3.5 g/sq cm and 2 to 25 MeV

Differential fluxes of gamma rays were calculated for energies of 2-25 MeV, zenith angles of 0-50 deg and 180-130 deg, and atmospheric depths from nominal sea level, 1000 g/sq cm, to float altitude, 3.5 g/sq cm residual atmosphere. Above 100 g/sq cm growth curves were constructed to estimate the contribution of the extraterrestrial gamma ray flux to the total downward-moving flux, while the upward-moving gamma rays were taken to be strictly of atmospheric origin. Below 100 g/sq cm, all gamma rays originate in the atmosphere. The downward atmospheric flux increases by almost two orders of magnitude between float altitude and the Pfotzer maximum, while the extraterrestrial flux is attenuated exponentially. Gamma rays produced by neutron interactions with the carbon in the scintillator liquid are eliminated by constructing growth curves for downward-moving gamma rays at high altitudes and are negligible compared with downward-moving gamma rays at lower altitudes and upward-moving gamma rays at all altitudes.

Ryan, J. M.↗
NASA NTRS1980

In vitro Ca-45/++/ uptake and exchange by otoconial complexes in high and low K/+/Na/+/ fluids

Recently, data have been accumulating to indicate that saccular and utricular otoconial complexes of the gravity receptor organs are dynamic and interact constantly with their environment. This study investigates the possibility that the ionic composition of the surrounding fluid influences calcium ion binding and release, and explores the importance of the K(+)/Na(+) ratio. Two in-vitro methods were developed, the first of which employed artificial endolymph and perilymph while ionically balanced fluids in which only the K(+)/Na(+) was altered were used in the second. The ability of rat complexes to take up Ca-45(++) during incubation with these fluids was assessed using liquid scintillation spectrometry. In vitro uptake of Ca-45(++) was greater in fluids with a high K(+)/Na(+) ratio than in fluids in which the ratio was low. The ability of the complexes to take up Ca-45(++) appeared to decline with age.

Ross, M. D.↗
NASA NTRS1985

Average features of the muon component of EAS or = 10(17) eV

Three 10 sq m liquid scintillators were situated at approximately 0 m, 150 m and 250 m from the center of the Haverah Park array. The detectors were shielded by lead/barytes giving muon detection thresholds of 317 MeV, 431 MeV and 488 MeV respectively. During part of the operational period the 431 MeV threshold was lowered to 313 MeV for comparison purposes. For risetime measurement fast phototubes were used and the 10% to 70% amplitude time interval was parameterized by T sub 70. A muon lateral density distribution of the form rho mu (R theta) = krho(500)0.94 1/R(1 + R/490)-eta has been fitted to the data for 120 m R 600 m and 0.27 (500) 2.55. The shower size parameter (500) is the water Cerenkov response at 500 m from the core of the extensive air showers (EAS) and is relatable to the primary energy. The results show general consistency.

Blake, P. R.↗
NASA NTRS1985

The spectrum of neutrons at 60 hg m(-2)

The rate of neutron interactions was measured for the energy range 7.5 to 60 MeV, using a 3.85 kg cell of liquid scintillator. The neutrons are selected by pulse shape discrimination, with anticoincidence counters used to reduce interference from muons transversing the scintillator. The observed flux is interpreted in terms of neutrons produced from environmental uranium and thorium, those resulting from the capture of negative muons in nuclei and those from fast muon interactions.

Barton, J. C.↗
NASA NTRS1985

Modular detector for deep underwater registration of muons and muon groups

Registration and identification of muons and muon groups penetrating into the ocean depth, can be performed using a modular multilayer detector with high resolution bidimensional readout - deep underwater calorimeter (project NADIR). Laboratory testing of a prototype sensor cell with liquid scintillator in light-tight casing, testifies to the practicability of the full-scale experiment within reasonable expences.

Demianov, A. I.↗
NASA NTRS1990

HgI2 low energy beta particle detector

An HgI2 device structure was designed and tested which allows HgI2 to be used to make low-energy beta-particle detectors. The devices detected tritium beta particles with an efficiency of about 25 percent. A protective encapsulant has been developed which should protect the devices for up to 20 years and will attenuate only a small fraction of the beta particles. It is noted that the devices hold significant promise to provide a practical alternative to liquid scintillation counters and gas flow-through proportional counters.

Shah, K. S.↗
NASA NTRS1995

Neutron measurements in near-Earth orbit with COMPTEL

The fast neutron flux in near-Earth orbit has been measured with the COMPTEL instrument on the Compton Gamma Ray Observatory (CGRO). For this measurement one of COMPTEL's seven liquid scintillator modules was used as an uncollimated neutron detector with threshold of 12.8 MeV. The measurements cover a range of 4.8 to 15.5 GV in vertical cutoff rigidity and 3 deg to 177 deg in spacecraft geocenter zenith angle. One of the measurements occurred near the minimum of the deepest Forbush decrease ever observed by ground-level neutron monitors. After correction for solar modulation, the total flux is well fitted by separable functions in rigidity and zenith angle. With the spacecraft pointed near the nadir the flux is consistent with balloon measurements of the atmospheric neutron albedo. The flux varies by about a factor of 4 between the extremes of rigidity and a factor of 2 between the extremes of zenith angle. The effect of the spacecraft mass in shielding the detector from the atmospheric neutron albedo is much more important than its role as a source of additional secondary neutrons. The neutron spectral hardness varies little with rigidity or zenith angle and lies in the range spanned by earlier atmospheric neutron albedo measurements.

Morris, D. J.↗
NASA NTRS1982

Communicable Disease Research

The COSMIC program FITLOS is used regularly by the Centers for Disease Control (CDC), for analyzing data from radioimmunoassays, which involve testing human body substances to provide information on how deficits or excesses of those substances affect a body's ability to ward off disease. A liquid scintillation counter's data is analyzed by the FITLOS program. FITLOS data, then aids in establishing reference methods for hospitals and other health laboratories in their radioimmunoassays. CDC's use of this program enabled them to avoid the cost of designing and developing a new program.

Source record↗
NASA NTRS2017

Investigation of Deuterium Loaded Materials Subject to X-Ray Exposure

Results are presented from an exploratory study involving x-ray irradiation of select deuterated materials. Titanium deuteride plus deuterated polyethylene, deuterated polyethylene alone, and for control, hydrogen-based polyethylene samples and nondeuterated titanium samples were exposed to x-ray irradiation. These samples were exposed to various energy levels from 65 to 280 kV with prescribed electron flux from 500 to 9000 μA impinging on a tungsten braking target, with total exposure times ranging from 55 to 280 min. Gamma activity was measured using a high-purity germanium (HPGe) detector, and for all samples no gamma activity above background was detected. Alpha and beta activities were measured using a gas proportional counter, and for select samples beta activity was measured with a liquid scintillator spectrometer. The majority of the deuterated materials subjected to the microfocus x-ray irradiation exhibited postexposure beta activity above background and several showed short-lived alpha activity. The HPE and nondeuterated titanium control samples exposed to the x-ray irradiation showed no postexposure alpha or beta activities above background. Several of the samples (SL10A, SL16, SL17A) showed beta activity above background with a greater than 4σ confidence level, months after exposure. Portions of SL10A, SL16, and SL17A samples were also scanned using a beta scintillator and found to have beta activity in the tritium energy band, continuing without noticeable decay for over 12 months. Beta scintillation investigation of as-received materials (before x-ray exposure) showed no beta activity in the tritium energy band, indicating the beta emitters were not in the starting materials.

x-ray irradiation↗
NASA NTRSDate not supplied

Contamination, Transportation or Transmutation in LENR Material Analyses

LENR experiments using various loading and triggering mechanisms rely on a variety of elemental and isotopic assays to determine LENR effects. These assays include optical microscopy, Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis (SEM/EDX), X-Ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). All of these methods observe the surface of a material. By dissolving or vaporizing the sample, Inductively Coupled Plasma Optical Element Spectroscopy (ICP-OES) can determine elemental composition (ppb) or with mass spectroscopy, isotopes (ICP/MS). One can use a focused ion beam (FIB) to cut open a sample and observe the “cut” with either SEM/EDX, or Time-of-Flight Secondary Ion Mass Spectroscopy (TOF-SIMS). High Purity Gamma Ray Spectroscopy (HPGe) and alpha/ beta Liquid Scintillator spectroscopy can be used. We’ve employed these assay methods in our NASA GRC research under both the Advanced Energy Conversion and Lattice Confinement Fusion Projects. However, there are limitations associated with each of these methods ranging from handling contamination, instrumental limitations including sensitivity and field of view, and sample preparation.

Low Energy Nuclear Reactions↗
DOE OSTI2021

NOvA as a Supernova Observatory

Extra-solar system neutrino astronomy was born in February 1987 when a supernova in a nearby satellite galaxy deposited a couple dozen neutrino events across three solar neutrino and nucleon decay experiments. This marked the first-ever observation of supernova neutrinos, as well as the first supernova in our galactic neighborhood visible to the naked eye in nearly 400 years. There is still much we do not know about the dynamics of these powerful explosions, but one thing is certain: neutrinos play a central role in driving a supernova. They also provide a unique opportunity for probing the interior conditions of a collapsing stellar core. Since 1987, the number of neutrino detectors around the world has grown. When the next supernova occurs, detectors must be ready to seize the moment and record data from this rare event that only happens a couple times per century. The NOvA experiment has been prepared for this for some time, but it has been unclear how well NOvA will be ab le to se parate supernova-like events from the large cosmogenic backgrounds and extract meaningful physical insight. In this thesis, I show that the cosmic-induced backgrounds in the NOvA detectors---especially the far detector---can be reduced to an acceptable level for core-collapse supernovae within $\sim$15 kpc and that a determination of the neutrino mass ordering can be made for nearby supernovae under certain conditions. This thesis paves the way for future sensitivity studies and eventual analyses of real supernova data, and shows that NOvA's liquid scintillator neutrino detectors are a capable supernova observatory.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Standard Analytical Methods for Pyrolysis Bio-Oils

There has been significant recent interest in the production of renewable fuels and chemicals from biomass and waste feedstocks. Pyrolysis pathways produce a liquid bio-oil product, which must be processed further, or upgraded, to yield fuel or chemical products. Bio-oils are very complex and often unstable samples, and research and development on upgrading processes needs reliable analytical information. In particular, chemical characterization techniques are needed to quantify both functional groups and individual compounds present in bio-oils. Reliable analytics are also needed to enable the bioenergy industry, as industrial facilities often have different analytical needs and capabilities than research facilities. In this presentation, we will discuss the development of a suite of standard analytical methods for pyrolysis bio-oils. Analytical methods to be discussed include: Determination of Carbon, Hydrogen, Nitrogen, and Oxygen in bio-oils; Accelerated Aging of Fast Pyrolysis Bio-oil using Carbonyl Titration; Determination of Water Content in Bio-oils by Volumetric Karl Fischer Titration; Determination of Carbon Functional Groups; Elemental Analysis of Bio-oils by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) - Na, K, Mg, Ca, S, P, and Fe; Determination of Phenolic Groups in Bio-oils using Revised Folin-Ciocalteu Methods: Single Cuvette and Plate Reader; Corrosivity of Bio-oils: Screening Test using Metal Leaching; Determination of Biogenic Content by 14C Measurement using Liquid Scintillation Counter. These new analytical methods are publicly available as Laboratory Analytical Procedures (https://www.nrel.gov/bioenergy/bio-oil-analysis.html), along with previously developed standard methods: GC-MS, Acid Titration, Carbonyl Titration, and 31P NMR. Additionally, the development of diffusion ordered NMR for characterization of bio-oil molecular weight will be discussed. Collectively, this suite of analytical methods represents the most comprehensive set of standard methods available for pyrolysis bio-oils. These standard methods are commonly used by the bioenergy community, and provide reliable information that enables research, scaleup, and industrial processing of biomass to produce renewable fuels and chemicals.

analytical↗
DOE OSTI2021

NOvA as a Supernova Observatory

Extra-solar system neutrino astronomy was born in February 1987 when a supernova in a nearby satellite galaxy deposited a couple dozen neutrino events across three solar neutrino and nucleon decay experiments. This marked the first-ever observation of supernova neutrinos, as well as the first supernova in our galactic neighborhood visible to the naked eye in nearly 400 years. There is still much we do not know about the dynamics of these powerful explosions, but one thing is certain: neutrinos play a central role in driving a supernova. They also provide a unique opportunity for probing the interior conditions of a collapsing stellar core. Since 1987, the number of neutrino detectors around the world has grown. When the next supernova occurs, detectors must be ready to seize the moment and record data from this rare event that only happens a couple times per century. The NOvA experiment has been prepared for this for some time, but it has been unclear how well NOvA will be ab le to se parate supernova-like events from the large cosmogenic backgrounds and extract meaningful physical insight. In this thesis, I show that the cosmic-induced backgrounds in the NOvA detectors---especially the far detector---can be reduced to an acceptable level for core-collapse supernovae within $\sim$15 kpc and that a determination of the neutrino mass ordering can be made for nearby supernovae under certain conditions. This thesis paves the way for future sensitivity studies and eventual analyses of real supernova data, and shows that NOvA's liquid scintillator neutrino detectors are a capable supernova observatory.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Comparison of AGR-3/4 Fission Product Transport Model to Measurements and Extraction of Diffusivities via Analytical Fits

A one-dimensional finite-element model based on the MOOSE framework has been constructed, and overall transport estimates are predicted based on available diffusivities and sorption isotherms in the extant literature. The predicted transport profiles are compared to experimental results, where such results are available, including total inventory analysis of gamma emitters, liquid scintillation results for Sr-90 concentrations, radial deconsolidation leach-burn-leach within compacts, tomographic reconstructions based on detailed gamma scanning and destructive physical sampling of several rings. The magnitude of expected transport to the sink ring is generally predicted by the model for silver and cesium, however, modeled detailed concentration profiles are not consistent with experimental results. Strontium and europium transport is not well characterized by model results.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2022

Towards a neutron multiplicity measurement with the Accelerator Neutrino Neutron Interaction Experiment

The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) is a 26 ton Gadolinium (Gd)-loaded water Cherenkov detector located on the Booster Neutrino Beam line at Fermilab. Its main goals are the measurement of the neutron multiplicity in neutrino-nucleus interactions as well as the cross-section of Charged Current Quasi-Elastic (CCQE) neutrino interactions on water. Besides the physics goals, the experiment also aims to be a testbed for new technologies such as Large Area Picosecond Photodetectors (LAPPDs) and Water-based Liquid Scintillators (WbLS). This thesis presents a preliminary measurement of the neutron multiplicity with {ANNIE}, using an analysis conducted on a fraction of the 2021 beam year. As preparatory measures, the efficiency of ANNIE's Front Muon Veto (FMV) was determined to be {$\bar{\varepsilon}_{\mathrm{FMV}} = (95.6 \pm 1.6)\%$} while the average efficiency for active scintillator paddles in the Muon Range Detector (MRD) was found to be {$\bar{\varepsilon}_ {\mathrm{MRD}} = (92.1 \pm 7.9)\%$}. Furthermore, the simulation framework used for ANNIE was validated and adapted to reproduce the experimental data by comparing the detector response for samples of Michel electrons, Americium Beryllium neutrons, and through-going muons. The analysis finds average neutron yields of {$\bar{n}_{\mathrm{data}} (\mathrm{beam}) = (0.272 \pm 0.010_{\mathrm{stat}})$} for an inclusive set of all identified muon neutrino candidates and {$\bar{n}_{\mathrm{data}} (\mathrm{beam,FV}) = (0.287 \pm 0.044_{\mathrm{stat}})$ for interactions which happened inside of the Fiducial Volume of ANNIE, which was optimized to increase the neutron detection acceptance. The presented neutron multiplicity values represent the number of detected neutrons after all event selection cuts and are not yet corrected for the neutron detection efficiency. An equivalent analysis on a simulated beam sample predicts neutron yields of $\bar{n}_{\mathrm{MC}}(\mathrm{beam}) = (0.515 \pm 0.0 07_{\mathrm{stat}})$ and $\bar{n}_{\mathrm{MC}}(\mathrm{beam,FV}) = (0.627 \pm 0.031_{\mathrm{stat}})$, indicating that the models tend to overpredict the number of neutrons produced in such interactions. Systematic errors have been briefly considered to contribute {$\sigma_{\mathrm{sys,FMV}} \sim 0.01\,$neutrons/$\nu$-interaction} due to the slight FMV inefficiency and {$\sigma_{\mathrm{sys,n}} \sim 0.05\,$neutrons/$\nu$-interaction} due to the neutron detection efficiency. Simulation studies further highlighted the importance of neutron detection in Diffuse Supernova Background (DSNB) searches. A combination of neutron tagging and Convolutional Neural Networks was found to reduce the most relevant Neutral Current Quasi-Elastic (NCQE) interaction background below the signal level, achieving a Signal-to-Background ratio of 4:1. In a further study, we investigated the positive impact of a deployment of a WbLS target on the energy reconstruction in ANNIE. WbLS provides a scintillation signal from hadronic recoils in addition to the charged lepton that can be included in neutrino energy reconstruction. It was found that a deployed WbLS volume in ANNIE improves the neutrino energy reconstruction from 14\% to 12\%, with the potential of going beyond this if more sophisticated reconstruction algorithms are developed in the future.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Future of the MUSiC Experiment Data

The Measurements of Uranium Subcritical and Critical (MUSiC) experiment was a highly enriched uranium (HEU) experiment performed at the National Criticality Experiments Research Center (NCERC) executed between December 2020 and April 2021. The experiment intended to measure criticality and reactor kinetics parameters in a bare HEU system. The experiment concurrently measured radiation signatures from the system while utilizing different neutron source types. This was an attempt to benchmark both detectors and analysis techniques against one another for identical measurements. The experiment consisted of the Rocky Flats HEU hemi-shells constructed into ten configurations spanning between deeply subcritical (about 14 kgs) to supercritical (about 60 kgs). Two of the ten configurations were supercritical and the other eight were subcritical. The two supercritical configurations, often referred to as the critical configurations, were documented into an International Criticality Safety Benchmark Evaluation Project (ICSBEP) benchmark evaluation and submitted to the technical review group (TRG). The subcritical configurations of the MUSiC experiment were examined using three different detection systems. The systems include: the NoMAD He-3 neutron detector which consists of 15 He-3 tubes surrounded by a polyethylene matrix, a liquid scintillator system called the Rossi-α Measurement Rapid Organic Discriminating Detector (RAM-RODD), and a trans-stilbene organic scintillator array (OSCAR) provided by the University of Michigan. The NoMAD and RAM-RODD data are planned to be evaluated in two separate ICSBEP evaluations utilizing neutron noise methods such as Feynman Variance-to-Mean, Rossi-α and the pulsed neutron source method. Each of the subcritical configurations were examined using three different source types including: a Cf-252 source in the center, with only the intrinsic neutron source in the HEU, and with an external D-T neutron generator.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗