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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Results of experiments devoted to searches for 2K capture on {sup 78}Kr and for the double-beta decay of {sup 136}Xe with the aid of proportional counters

A brief description of two low-background setups deployed at the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) and intended for searches for two types of double-beta decay of inert-gas isotopes-2K capture on {sup 78}Kr and the double-beta decay of {sup 136}Xe-is given. The two setups in question have similar structures and employ identical large high-pressure copper proportional counters as detectors. Upon a treatment of data from measurements with krypton samples differing in the content of the isotope {sup 78}Kr, the spectrum for an enriched sample revealed an excess of events at a statistical-significance level of about two standard deviations (2{sigma}). If one attributes this excess to 2K(2{nu}) capture on {sup 78}Kr, the respective half-life is T{sub 1/2} = 1.4{sub -0.7}{sup +2.3} Multiplication-Sign 10{sup 22} yr at a 90% C.L. A treatment of data from measurements with xenon samples differing in content of the isotope {sup 136}Xe led to the appearance of an excess of events in the spectrum for an enriched sample at a statistical-significance level of about 2.2{sigma}. If one assumes that this excess is due to the two-neutrino double-beta decay of {sup 136}Xe, then the respective half-life is T{sub 1/2} = 5.8{sub -1.8}{sup +4.7} Multiplication-Sign 10{sup 21} yr.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Self-consistent approach to beta decay and delayed neutron emission

A brief overview of the recent self-consistent studies of nuclear beta decay is given including the relativistic quasi-particle random-phase approximation or QRPA and Finite Amplitude Method. The results of our self-consistent continuum QRPA model based on the density functional description of the ground states are presented. They are in a good agreement with the recent experimental beta-decay half-lives and delayed neutron emission branchings for the nuclei approaching (and beyond) the neutron closed shells N = 50 near {sup 78}Ni and N = 82 near {sup 132}Sn. A comparison with the recent calculations from relativistic QRPA model, Finite Amplitude Method and semi-microscopic finite-range droplet model is performed. An importance of the quasi-particle phonon coupling is stressed for the description of the beta decay and delayed multi-neutron emission rates. A strategy of extending our approach to the deformed nuclei and the open problems are discussed.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2016

Search for the Neutrino Less Double Beta Decay

During the past few years our understanding of neutrino properties has reached a new level, with experiments such as Super-K, SNO, KamLAND, and others obtaining exciting results. Major questions such as “Do neutrinos have mass?” and “Do neutrinos oscillate?” now have positive answers. However, an extensive program of neutrino research remains. Undoubtedly, the most important of these is the question pointed out by the National Research Council in its February 2002 report “Connecting Quarks with the Cosmos”, specifically: What are the masses of neutrinos and how have they shaped the evolution of the Universe? The MAJORANA collaboration has proposed to build the world’s most sensitive one-ton scale experiment to search for neutrino less double beta decay to answer this question. In its initial stage, the collaboration is building a prototype MAJORANA DEMONSTRATOR (MJD) experiment consisting of detectors made out of enriched Ge 76 with a total sensitive mass of ~30 kg. This will accomplish two goals. First, it will test not yet confirmed claim for observation of neutrino-less double beta decay. Second, it will establish that the selected technology is capable of extension to a one-ton experiment with sufficient sensitivity to measure neutrino mass m ββ down to 10 meV. To achieve the last goal, collaboration must demonstrate that a background level of 1 count per year per 4 keV per ton of detector is achievable. The University of Tennessee (UT) neutrino group has made a major commitment to the MJD. P.I. accepted the responsibility for one of the major tasks of the experiment, “Materials and Assay Task” which is crucial to the achievement of low background levels required for the experiment. In addition, the UT group is committed to construct, commission, and operate the MJD active veto system. Those activities were supported by NP-DOE via program funding for “Search for the Neutrino Less Double Beta Decay” at the University of Tennessee. We would like to report the results and achievements under this grant for Material and Assay Task and for task to build and deploy veto system for the Majorana Experiment separately.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

In Situ X-ray Radiography and Computational Modeling to Predict Grain Morphology in $\beta$-Titanium during Simulated Additive Manufacturing

The continued development of metal additive manufacturing (AM) has expanded the engineering metallic alloys for which these processes may be applied, including beta-titanium alloys with desirable strength-to-density ratios. To understand the response of beta-titanium alloys to AM processing, solidification and microstructure evolution needs to be investigated. In particular, thermal gradients (Gs) and solidification velocities (Vs) experienced during AM are needed to link processing to microstructure development, including the columnar-to-equiaxed transition (CET). In this work, in situ synchrotron X-ray radiography of the beta-titanium alloy Ti-10V-2Fe-3Al (wt.%) (Ti-1023) during simulated laser-powder bed fusion (L-PBF) was performed at the Advanced Photon Source at Argonne National Laboratory, allowing for direct determination of Vs. Two different computational modeling tools, SYSWELD and FLOW-3D, were utilized to investigate the solidification conditions of spot and raster melt scenarios. The predicted Vs obtained from both pieces of computational software exhibited good agreement with those obtained from in situ synchrotron X-ray radiography measurements. The model that accounted for fluid flow also showed the ability to predict trends unobservable in the in situ synchrotron X-ray radiography, but are known to occur during rapid solidification. A CET model for Ti-1023 was also developed using the Kurz–Giovanola–Trivedi model, which allowed modeled Gs and Vs to be compared in the context of predicted grain morphologies. Both pieces of software were in agreement for morphology predictions of spot-melts, but drastically differed for raster predictions. The discrepancy is attributable to the difference in accounting for fluid flow, resulting in magnitude-different values of Gs for similar Vs.

36 MATERIALS SCIENCE↗
NASA NTRS1998

Blockade of beta-adrenoceptors enhances cAMP signal transduction in vivo

The aim of this study was to determine whether the blockade of beta-adrenoceptors would enhance cAMP-mediated signal transduction processes in vivo. The administration of the membrane permeable cAMP analogue, 8-(4-chlorophenylthiol)-cAMP (8-CPT-cAMP, 10 micromol/kg, i.v.) produced an increase in heart rate (+27 +/- 2%, P < 0.05), a fall in mean arterial blood pressure (-21 +/- 3%, P < 0.05) and falls in hindquarter (-12 +/- 3%, P < 0.05) and mesenteric (-32 +/- 3%, P < 0.05) vascular resistances in pentobarbital-anesthetized rats. The beta-adrenoceptor antagonist, propranolol (1 mg/kg, i.v.) lowered heart rate (-12 +/- 3%, P < 0.05) but did not affect mean arterial blood pressure or vascular resistances. The tachycardia, hypotension and vasodilation produced by 8-CPT-cAMP were exaggerated after administration of propranolol (P < 0.05 for all comparisons). The nitric oxide-donor, sodium nitroprusside (2 microg/kg, i.v.), produced falls in mean arterial blood pressure and vascular resistances of similar magnitude to those produced by 8-CPT-cAMP. These sodium nitroprusside-induced responses were unaffected by propranolol (P < 0.05 for all comparisons). Sodium nitroprusside also produced a minor increase in heart rate (+5 +/- 1%, P < 0.05) which was abolished by propranolol. These findings suggest that 8-CPT-cAMP directly increases heart rate and that blockade of beta-adrenoceptors enhances the potency of cAMP within the heart and vasculature.

Non-NASA Center↗
NASA NTRS1995

Anti-dopamine beta-hydroxylase immunotoxin-induced sympathectomy in adult rats

Anti-dopamine beta-hydroxylase immunotoxin (DHIT) is an antibody-targeted noradrenergic lesioning tool comprised of a monoclonal antibody against the noradrenergic enzyme, dopamine beta-hydroxylase, conjugated to saporin, a ribosome-inactivating protein. Noradrenergic-neuron specificity and completeness and functionality of sympathectomy were assessed. Adult, male Sprague-Dawley rats were given 28.5, 85.7, 142 or 285 micrograms/kg DHIT i.v. Three days after injection, a 6% to 73% decrease in the neurons was found in the superior cervical ganglia of the animals. No loss of sensory, nodose and dorsal root ganglia, neurons was observed at the highest dose of DHIT. In contrast, the immunotoxin, 192-saporin (142 micrograms/kg), lesioned all three ganglia. To assess the sympathectomy, 2 wk after treatment (285 micrograms/kg), rats were anesthetized with urethane (1 g/kg) and cannulated in the femoral artery and vein. DHIT-treated animals' basal systolic blood pressure and heart rate were significantly lower than controls. Basal plasma norepinephrine levels were 41% lower in DHIT-treated animals than controls. Tyramine-stimulated release of norepinephrine in DHIT-treated rats was 27% of controls. Plasma epinephrine levels of DHIT animals were not reduced. DHIT-treated animals exhibited a 2-fold hypersensitivity to the alpha-adrenergic agonist phenylephrine. We conclude that DHIT selectively delivered saporin to noradrenergic neurons resulting in destruction of these neurons. Anti-dopamine beta-hydroxylase immunotoxin administration produces a rapid, irreversible sympathectomy.

NASA Discipline Regulatory Physiology↗
DOE OSTI2011

Theoretical Study of the Mechanism Behind the para-Selective Nitration of Toluene in Zeolite H-Beta

Periodic density functional theory calculations were performed to investigate the origin of the favorable para-selective nitration of toluene exhibited by zeolite H-beta with acetyl nitrate nitration agent. Energy calculations were performed for each of the 32 crystallographically unique Bronsted acid sites of a beta polymorph B zeolite unit cell with multiple Bronsted acid sites of comparable stability. However, one particular aluminum T-site with three favorable Bronsted site oxygens embedded in a straight 12-T channel wall provides multiple favorable proton transfer sites. Transition state searches around this aluminum site were performed to determine the barrier to reaction for both para and ortho nitration of toluene. A three-step process was assumed for the nitration of toluene with two organic intermediates: the pi- and sigma-complexes. The rate limiting step is the proton transfer from the sigma-complex to a zeolite Bronsted site. The barrier for this step in ortho nitration is shown to be nearly 2.5 times that in para nitration. This discrepancy appears to be due to steric constraints imposed by the curvature of the large 12-T pore channels of beta and the toluene methyl group in the ortho approach that are not present in the para approach.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2011

Sensitivity of CUORE to Neutrinoless Double-Beta Decay

In this paper, we study the sensitivity of CUORE, a bolometric double-beta decay experiment under construction at the Laboratori Nazionali del Gran Sasso in Italy. Two approaches to the computation of experimental sensitivity are discussed and compared, and the formulas and parameters used in the sensitivity estimates are provided. Assuming a background rate of 10{sup -2} cts/(keV kg y), we find that, after 5 years of live time, CUORE will have a 1 {sigma} sensitivity to the neutrinoless double-beta decay half-life of {caret T{sup 0{nu}}{sub 1/2}}(1{sigma} ) = 1.6x 10{sup 26} y and thus a potential to probe the effective Majorana neutrino mass down to 41-95 meV; the sensitivity at 1.64{sigma} , which corresponds to 90% C.L., will be {caret T{sup 0{nu}}{sub 1/2}(1.64{sigma} }) = 9.5x10{sup 25} y. This range is compared with the claim of observation of neutrinoless double-beta decay in {sup 76}Ge and the preferred range in the neutrino mass parameter space from oscillation results.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Sensitivity and Discovery Potential of CUORE to Neutrinoless Double-Beta Decay

We present a study of the sensitivity and discovery potential of CUORE, a bolometric double-beta decay experiment under construction at the Laboratori Nazionali del Gran Sasso in Italy. Two approaches to the computation of experimental sensitivity for various background scenarios are presented, and an extension of the sensitivity formulation to the discovery potential case is also discussed. Assuming a background rate of 10 -2 cts/(keV kg y), we find that, after 5 years of live time, CUORE has a 1 sigma sensitivity to the neutrinoless double-beta decay half-life of T$0v\atop{1/2}$(1θ) = 1.6 \times 10 26 y and thus a potential to probe the effective Majorana neutrino mass down to 40-100 meV; the sensitivity at 1.64 sigma, which corresponds to 90% C.L., will be T$0v\atop{1/2}$(1.64θ) = 9.5 \times 10 25 y. This range is compared with the claim of observation of neutrinoless double-beta decay in 76 Ge and the preferred range of the neutrino mass parameter space from oscillation results.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2010

{beta} and Isomeric Decay of Nuclei in the {sup 100}Sn Region

The decay properties of rp-process nuclei in the vicinity of {sup 100}Sn have been studied at the National Superconducting Cyclotron Laboratory (NSCL). The measured {beta}-decay half-life for {sup 100}Sn is 0.55{sub -0.31}{sup +0.70} s, in agreement with a previous measurement. In {sup 98}In, the {beta}-decay of the ground state plus that of a long lived isomer were observed with half-lives of 47(13) ms and 0.66(40) s respectively. The half-life of {sup 96}Cd, measured for the first time, is 1.03{sub -0.21}{sup +0.24} s; however, the existence of a predicted isomeric state in this nucleus could not be confirmed. Additionally, a gamma cascade de-exciting a {mu}-isomer in the odd-odd nucleus {sup 96}Ag was observed. The implications of the measured half-life of {sup 96}Cd on the calculated rp-process final abundances are discussed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Simulations of Bunch Merging in a Beta Beam Decay Ring

To further study neutrino oscillation properties a Beta Beam facility has been proposed. Beta decaying ions with high kinetic energy are stored in a storage ring (''Decay Ring'') with straight sections to create pure focused (anti) electron neutrino beams. However to reach high sensitivity to neutrino oscillation parameters in the experiment the bunched beam intensity and duty cycle in the DR have to be optimized. The first CERN-based scenario, using {sup 6}He and {sup 18}Ne as neutrino sources, has been studied using a bunch merging RF scheme. Two RF cavities at different frequencies are used to capture newly injected bunches and then merge them into the stored bunches. It was shown that this scheme could satisfy the requirements on intensity and duty cycle set by the experiment. This merging scheme has now been revised with new simulation software providing new results for {sup 6}He and {sup 18}Ne. Furthermore bunch merging has been studied for the second CERN-based scenario using {sup 8}Li and {sup 8}B.

43 PARTICLE ACCELERATORS↗
DOE OSTI2010

Beta Neutrino Correlation Measurement with Trapped Radioactive Ions

The beta-neutrino angular correlation coefficient provides a sensitive observable to search for physics beyond the standard electroweak model in nuclear beta decay. We address here the measurement of this parameter in the pure Gamow-Teller transition of {sup 6}He. A deviation from the standard model prediction would indicate the existence of tensor like couplings, possibly mediated by new bosons like leptoquarks. The aim of the LPCTrap experiment is to measure this coefficient with a statistical uncertainty of 0.5% using a novel transparent Paul trap. The status of the experiment is briefly presented along with the work in progress.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Introduction to Double Beta Decay

While the neutrino oscillation experiments have measured non-zero square mass differences between neutrino flavors, the double beta decay is the most sensitive process to the absolute mass of the neutrinos and the only that can distinguish whether neutrino is a Dirac or a Majorana particle. These are a few but not the only reasons that many efforts, both theoretically and experimentally, are dedicated to the study of this process. In this lecture I'll give a short introduction to the double beta decay process. Different decay modes and mechanisms, a short history, decay rates and extraction of the neutrino mass parameter are presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Role of short range correlations on nuclear matrix elements of neutrinoless double beta decay

Employing four different parametrization of the pairing plus multipolar type of effective two-body interaction and three different parametrizations of Jastrow-type of short range correlations, the uncertainties in the nuclear transition matrix elements due to the exchange of light as well as heavy Majorana neutrino for the 0{sup +}{yields}0{sup +} transition of neutrinoless positron {beta}{beta} decay are estimated in the PHFB model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Theoretical mean-field and experimental occupation probabilities in the double-beta decay system {sup 76}Ge to {sup 76}Se

Usual Woods-Saxon single-particle levels with BCS pairing are not able to reproduce the experimental occupation probabilities of the proton and neutron levels 1p{sub 3/2}, 1p{sub 1/2}, 0f{sub 5/2}, and 0g{sub 9/2} in the double-beta decay system {sup 76}Ge to {sup 76}Se. Shifting down the 0g{sub 9/2} level by hand can explain the data, but it is not satisfactory. Here it is shown that a self-consistent Hartree-Fock+BCS approach with experimental deformations for {sup 76}Ge and {sup 76}Se may decisively improve the agreement with the recent data on occupation probabilities by J. P. Schiffer et al. [Phys. Rev. Lett. 100, 112501 (2008)] and B. P. Kay et al. [Phys. Rev. C 79, 021301(R) (2009)]. Best agreement with available data on {sup 76}Ge and {sup 76}Se, as well as on neighbor isotopes, is obtained when the spin-orbit strength for neutrons is allowed to be larger than that for protons. The two-neutrino double-beta decay matrix element is also shown to agree with the data.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2010

Experimental study of the beta-delayed proton decays of {sup 145,147}Er

The beta-delayed proton decays of {sup 145,147}Er have been studied experimentally using the {sup 58}Ni+{sup 92}Mo reaction at beam energy of 383 MeV. On the basis of a He-jet apparatus coupled with a tape transport system, the beta-delayed proton radioactivities both from the nus{sub 1/2} ground state and the nuh{sub 11/2} isomer in {sup 145,147}Er were observed by proton-gamma coincidence measurements. By analyzing the time distributions of the 4{sup +}->2{sup +}gamma transitions in the granddaughter nuclei {sup 144,146}Dy, the half-lives of 1.0+-0.3 s and 1.6+-0.2 s have been deduced for the nuh{sub 11/2} isomers in {sup 145,147}Er, respectively.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2010

Toward precise Q{sub EC} values for the superallowed 0{sup +}->0{sup +} beta decays of T=2 nuclides: The masses of {sup 20}Na, {sup 24}Al, {sup 28}P, and {sup 32}Cl

High-precision measurements of superallowed 0{sup +}->0{sup +} beta decays of T=2 nuclides such as {sup 20}Mg, {sup 24}Si, {sup 28}S, and {sup 32}Ar can contribute to searches for physics beyond the standard model of particle physics if the Q{sub EC} values are accurate to a few keV or better. As a step toward providing precise Q{sub EC} values for these decays, the ground-state masses of the respective daughter nuclei {sup 20}Na, {sup 24}Al, {sup 28}P, and {sup 32}Cl have been determined by measuring the ({sup 3}He,t) reactions leading to them with the {sup 36}Ar({sup 3}He,t){sup 36}K reaction as a calibration. A quadrupole-dipole-dipole-dipole (Q3D) magnetic spectrograph was used together with thin ion-implanted carbon-foil targets of {sup 20}Ne, {sup 24}Mg, {sup 28}Si, {sup 32}S, and {sup 36}Ar. The masses of {sup 20}Na and {sup 32}Cl are found to be in good agreement with the values from the 2003 Atomic Mass Evaluation (AME03) [G. Audi, A. H. Wapstra, and C. Thibault, Nucl. Phys. A 729, 337 (2003)], and the precision has been improved by a factor of 6 in both cases. The masses of {sup 24}Al and {sup 28}P are found to be higher than the values from AME03 by 9.5 keV (3.2sigma) and 11.5 keV (3.6sigma), respectively, and the precision has been improved by a factor of 2.5 in both cases. The new {sup 32}Cl mass is used together with the excitation energy of its lowest T=2 level and the mass of {sup 32}Ar to derive an improved superallowed Q{sub EC} value of 6087.3(22) keV for this case. The effects on quantities related to standard-model tests including the beta-nu correlation coefficient a and the isospin-symmetry-breaking correction delta{sub C} are examined for the A=32 case.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2010

Double-{beta} decay Q value of {sup 150}Nd

The double-{beta} decay Q value of {sup 150}Nd was determined by using the JYFLTRAP Penning trap mass spectrometer. The measured mass difference between {sup 150}Nd and {sup 150}Sm is 3371.38(20) keV. This new value deviates by 3.7 keV from the previously adopted value of 3367.7(22) keV and is a factor of 10 more precise. Accurate knowledge of this Q value is important because {sup 150}Nd is a primary candidate to be used in the search for neutrinoless double-{beta} decay modes in several experiments.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗