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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Innovative Safety Ideas for Fusion Experimental Machines

Throughout the early stages of design of fusion experimental devices, such as ITER, safety experts have worked with designers to incorporate safety features into the design. Recent efforts have focused on passive safety features. Although designs of near-term fusion machines may appear consistent with expected regulatory requirements, the safety characteristics can potentially be more attractive. Here, a variety of suggestions that appear promising in terms of improving safety are given. These include new concepts, innovative technologies, further support of past concepts, and possible modification to operating scenarios. Some technical discussion on the feasibility of the proposals is provided. The ideas are generally conceptual at this stage and require further assessment and development work. However, each has the potential for enhancing the safety of experimental devices.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2014

Nuclear Data Sheets for A = 54

The 2005 evaluation for A=54 (2006Hu08) has been updated. Detailed experimental nuclear structure data and decay data for all nuclei with mass chain A=54 are presented in this current evaluation. The new data and information are given in following datasets: {sup 54}Ca: {sup 9}Be({sup 76}Ge, X) and Be({sup 55}Sc, p), ({sup 56}Ti, 2p) {sup 54}Sc: {sup 54}Ca β{sup −} decay and {sup 54}Sc IT decay {sup 54}Ti: {sup 54}Sc β{sup −} decay {sup 54}Cr: {sup 54}Mn ε decay, {sup 56}Fe(μ, nupng), and {sup 238}U({sup 64}Ni, Xγ) {sup 54}Mn: {sup 51}V({sup 20}Ne, Xγ), {sup 55}Mn(p, pn), and {sup 56}Fe(μ, nu2ng) {sup 54}Fe: {sup 58}Ni α decay, {sup 9}Be({sup 55}Co, Xγ), {sup 54}Fe(e, e'), {sup 54}Fe(p, p'), and Coulomb Excitation {sup 54}Co: {sup 54}Ni ε decay, {sup 55}Cu εp decay, {sup 28}Si({sup 32}S, αpnγ), {sup 54}Fe(p,n), and {sup 54}Fe({sup 3}He, t) {sup 54}Ni: {sup 54}Ni IT decay, {sup 55}Zn εp decay, {sup 9}Be({sup 55}Ni, Xγ), and {sup 24}Mg({sup 32}S, Xγ) {sup 54}Zn: Ni({sup 58}Ni, X)

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Final scientific and technical report: New experiments to measure the neutrino mass scale

In this work, we made material progress towards future measurements of the mass of the neutrino. The neutrino is a fundamental particle, first observed in the 1950s and subjected to particularly intense study over the past 20 years. It is now known to have some, non-zero mass, but we are in an unusual situation of knowing the mass exists but not knowing what value it takes. The mass may be determined by precise measurements of certain radioactive decay distributions, particularly the beta decay of tritium. The KATRIN experiment is an international project which is nearing the beginning of a tritium measurement campaign using a large electrostatic spectrumeter. This research included participation in KATRIN, including construction and delivery of a key calibration subsystem, the ``Rear Section''. To obtain sensitivity beyond KATRIN's, new techniques are required; this work included R&D on a new technique we call CRES (Cyclotron Resonance Electron Spectroscopy) which has promise to enable even more sensitive tritium decay measurements. We successfully carried out CRES spectroscopy in a model system in 2014, making an important step towards the design of a next-generation tritium experiment with new neutrino mass measurement abilities.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Uncertainties in Astrophysical β-decay Rates from the FRDM

β{sup −}-decay rates are of crucial importance in stellar evolution and nucleosynthesis, as they are a key component in stellar processes. Tabulated values of the decay rates as functions of both temperature T and density ρ are necessary input to stellar evolution codes such as MESA, or largescale nucleosynthesis simulations such as those performed by the NuGrid collaboration. Therefore, it is interesting to know the uncertainties in these rates and the effects of these uncertainties on stellar structure and isotopic yields. We have calculated β-strength functions and reaction rates for nuclei ranging from {sup 16}O to {sup 339}136, extending from the proton drip line to the neutron drip line based on a quasi-particle random-phase approximation (QRPA) in a deformed folded-Yukawa single-particle model. Q values are determined from the finite-range droplet mass model (FRDM). We have investigated the effect of model uncertainty on astrophysical β{sup −}-decay rates calculated by the FRDM. The sources of uncertainty considered are Q values and deformation. The rates and their uncertainties are generated for a variety of temperature and density ranges, corresponding to key stellar processes. We demonstrate the effects of these rate uncertainties on isotopic abundances using the NuGrid network calculations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Fundamental Neutron Physics: Theory and Analysis

The goal of the proposal was to study the possibility of searching for manifestations of new physics beyond the Standard model in fundamental neutron physics experiments. This involves detailed theoretical analyses of parity- and time reversal invariance-violating processes in neutron-induced reactions, properties of neutron β-decay, and the precise description of properties of neutron interactions with nuclei. To describe neutron-nuclear interactions, we use both the effective field theory approach and the theory of nuclear reaction with phenomenological nucleon potentials for the systematic description of parity- and time reversal-violating effects in the consistent way. A major emphasis of our research during the funding period has been the study of parity violation (PV) and time reversal invariance violation (TRIV) in few-body systems. We studied PV effects in non-elastic processes in three-nucleon system using both ”DDH-like” and effective field theory (EFT) approaches. The wave functions were obtained by solving three-body Faddeev equations in configuration space for a number of realistic strong potentials. The observed model dependence for the DDH approach indicates intrinsic difficulty in the description of nuclear PV effects, and it could be the reason for the observed discrepancies in the nuclear PV data analysis. It shows that the DDH approach could be a reasonable approach for analysis of PV effects only if exactly the same strong and weak potentials are used in calculating all PV observables in all nuclei. However, the existing calculations of nuclear PV effects were performed using different potentials; therefore, strictly speaking, one cannot compare the existing results of these calculations among themselves.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

First Compilation and Evaluation of Beta-Delayed Neutron Emission Probabilities and Associated Half-Lives for A ≤ 72 Nuclei

A comprehensive compilation and evaluation of beta-delayed neutron (β{sup −}n) emission probabilities, P{sub n}, and associated half-lives for A ≤ 72 nuclei has been performed for the first time. The recommended values have been used to analyze the systematics of β{sup −}n emission in this region. The ratio P{sub n}/T{sub 1/2} is better correlated with the Q-value of the β{sup −}n decay mode than the previously proposed Kratz-Herrmann Formula (KHF). The recommended values are also compared with theoretical quasi-particle random phase approximation (QRPA) calculations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

R-matrix Analysis of Reactions in the {sup 9}B Compound System

Recent activity in solving the ‘lithium problem’ in big bang nucleosynthesis has focused on the role that putative resonances may play in resonance-enhanced destruction of {sup 7}Li. Particular attention has been paid to the reactions involving the {sup 9}B compound nuclear system, d+{sup 7}Be→{sup 9}B. These reactions are analyzed via the multichannel, two-body unitary R-matrix method using the code EDA developed by Hale and collaborators. We employ much of the known elastic and reaction data, in a four-channel treatment. The data include elastic {sup 3}He+{sup 6}Li differential cross sections from 0.7 to 2.0 MeV, integrated reaction cross sections for energies from 0.7 to 5.0 MeV for {sup 6}Li({sup 3}He,p){sup 8}Be{sup *} and from 0.4 to 5.0 MeV for the {sup 6}Li({sup 3}He,d){sup 7}Be reaction. Capture data have been added to an earlier analysis with integrated cross section measurements from 0.7 to 0.825 MeV for {sup 6}Li({sup 3}He,γ){sup 9}B. The resulting resonance parameters are compared with tabulated values, and previously unidentified resonances are noted. Our results show that there are no near d+{sup 7}Be threshold resonances with widths that are 10's of keV and reduce the likelihood that a resonance-enhanced mass-7 destruction mechanism, as suggested in recently published work, can explain the {sup 7}Li problem.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

SU-E-I-80: Beta-Minus Emitting Radiotracers Improves Molecular Endoscopy

Purpose: Molecular Endoscopy using Cerenkov Luminescence can be used to monitor the distribution of many clinically-available PET and SPECT probes for endoscopic applications. A main limitation of Cerenkov is its limited sensitivity to small concentrations of radiotracer when using light guides s. Herein we demonstrate that the use of a high energy beta emitting radioisotope, exemplified here with 90Y provides superior sensitivity to 18F because of its higher light output and its lack of corresponding gamma emission. Methods: A series of phantom experiments were performed to compare the sensitivity and noise of the CLE system for imaging 90Y and 18F. Three vials of known concentrations of 90Y (0.008 μCi, 0.08 μCi, 1 μCi) were placed in centrifuge tubes and isolated from each other. One vial of 18F (100 μCi) was placed in the imaging chamber and imaged over the course of decay (19 hours, 43 minutes, or ∼10 half-lives). Image time-points were formed from 5-minute integrations. Results: Using an SNR of 10 to define the noise-floor, the 90Y minimum detectable activity was 0.056 μCi. To the contrast, the minimum detectable activity for 18F was 11.63 μCi. These data demonstrate a 207-fold improvement in SNR of 90Y compared to 18F, when controlled for activity. Conclusion: This study demonstrated that a pure β- radionuclide such as 90Y be used is superior to 18F for Cerenkov Endoscopy. Further study is needed to demonstrate its utility in preclinical studies, endoscopic applications, intraoperative, and radiotherapy applications.

07 ISOTOPE AND RADIATION SOURCES↗