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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Impact of Consolidation Radiation Therapy in Stage III-IV Diffuse Large B-cell Lymphoma With Negative Post-Chemotherapy Radiologic Imaging

Purpose: While consolidation radiation therapy (i.e., RT administered after chemotherapy) is routine treatment for patients with early-stage diffuse large B-cell lymphoma (DLBCL), the role of consolidation RT in stage III-IV DLBCL is controversial. Methods and Materials: Cases of patients with stage III-IV DLBCL treated from 1991 to 2009 at Duke University, who achieved a complete response to chemotherapy were reviewed. Clinical outcomes were calculated using the Kaplan-Meier method and were compared between patients who did and did not receive RT, using the log-rank test. A multivariate analysis was performed using Cox proportional hazards model. Results: Seventy-nine patients were identified. Chemotherapy (median, 6 cycles) consisted of anti-CD20 antibody rituximab combined with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP; 65%); cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP; 22%); or other (13%). Post-chemotherapy imaging consisted of positron emission tomography (PET)/computed tomography (CT) (73%); gallium with CT (14%); or CT only (13%). Consolidation RT (median, 25 Gy) was given to involved sites of disease in 38 (48%) patients. Receipt of consolidation RT was associated with improved in-field control (92% vs. 69%, respectively, p = 0.028) and event-free survival (85% vs. 65%, respectively, p = 0.014) but no difference in overall survival (85% vs. 78%, respectively, p = 0.15) when compared to patients who did not receive consolidation RT. On multivariate analysis, no RT was predictive of increased risk of in-field failure (hazard ratio [HR], 8.01, p = 0.014) and worse event-free survival (HR, 4.3, p = 0.014). Conclusions: Patients with stage III-IV DLBCL who achieve negative post-chemotherapy imaging have improved in-field control and event-free survival with low-dose consolidation RT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Nuclear Data Sheets for A=73☆

Experimental nuclear structure data for the known A=73 isobaric nuclides (Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Kr, Rb and Sr) have been evaluated, and presented together with Adopted properties of level energies, and associated γ rays. The decay data for these nuclides have also been evaluated, providing Adopted values of γ and β radiations, and log ft values. For {sup 73}Mn, only the isotopic identification has been established, with no knowledge of its g.s. half-life. For {sup 73}Fe, {sup 73}Co and {sup 73}Sr, only the ground states and their half-lives are known with no information about the excited states. For {sup 73}Ni, {sup 73}Cu, {sup 73}Zn and {sup 73}Rb, little data are available for excited states. The half-life and decay modes of possibly proton-unbound {sup 73}Rb need firmly established. {sup 73}Ga structure presents a special challenge in that the 1/2{sup −} ground state and the first 3/2{sup −} state have recently been proposed, in a Coulomb excitation experiment by 2010Di14, to form an almost degenerate doublet with an estimated spacing of 229 Th with its first excited state at 7.8 eV, and {sup 235}U with its first excited state at 76 eV. Ultra-high resolution gamma-ray spectroscopic studies are warranted to search for the low-lying (73 Ga, and to determine its half-life. Level structures of {sup 73}Ga, {sup 73}Ge, {sup 73}As, {sup 73}Se, {sup 73}Br and {sup 73}Kr are quite well known, although decay schemes of radioactive ground states of {sup 73}Co, {sup 73}Cu and {sup 73}Br are considered incomplete. The reactions and decays for which no new experimental information has become available since the 2003 update have undergone revisions to incorporate conversion coefficients from BrIcc code, and evaluated Q values from 2017Wa10, but essential content of such datasets may have remained the same as in previous evaluations. In this respect the present work greatly benefited from all the previous NDS evaluations (2004Si08,1993Ki25,1987Ki13, 1980Ek01,1974Al33), but at the same time data presented herein supersede all the previous published evaluations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2012

Discovery of gallium, germanium, lutetium, and hafnium isotopes

Currently, twenty-eight gallium, thirty-one germanium, thirty-five lutetium, and thirty-six hafnium isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Photocurrent from Single Collision 14 MeV Neutrons in GaN and GaAs

Accurate predictions of device performance in 14 MeV neutron environments relies upon understanding the recoil cascades that may be produced. Recoils from 14 MeV neutrons impinging on both gallium nitride (GaN) and gallium arsenide (GaAs) devices were modeled and compared to the recoil spectra of devices exposed to 14 MeV neutrons. Recoil spectra were generated using nuclear reaction modeling programs and converted into an ionizing energy loss (IEL) spectrum. We measured the recoil IEL spectra by capturing the photocurrent pulses produced by single neutron interactions with the device. Good agreement, with a factor of two, was found between the model and experiment under strongly-depleted conditions. However, this range of agreement between model and experiment decreased significantly when the bias was removed, indicating partial energy deposition due to cascades that escape the active volume of the device not captured by the model. Consistent event rates across multiple detectors confirm the reliability of our neutron recoil detection method.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Application of a Focused, Pulsed X-Ray Beam to the Investigation of Single-Event Transients in Al 0.3 Ga 0.7 N/GaN HEMTs

A focused, pulsed x-ray beam was used to compare SET characteristics in pristine and proton-irradiated Al 0.3 Ga 0.7 N/GaN HEMTs. Measured SET amplitudes and trailing-edge decay times were analyzed as was the collected charge, obtained by integrating the SET pulses over time. SETs generated in proton-irradiated HEMTs differed significantly from those in pristine HEMTs with regard to the decay times and collected charge. The decay times have previously been shown to be attributed to charge trapping by defect states that are caused either by imperfect material growth conditions or by protoninduced displacement damage. The longer decay times observed for proton-irradiated HEMTs are attributed to the presence of additional deep traps created when protons lose energy as they collide with the nuclei of constituent atoms. Comparison of electrical parameters measured before and immediately following exposure to the focused x-ray beam showed little change, confirming the absence of significant charge buildup in passivation layers by the x-rays themselves. In conclusion, a major advantage of the pulsed x-ray technique is that the region under the metal gate can be probed for single-event transients from the top side, an approach incompatible with pulsed-laser SEE testing that involves the use of visible light.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2012

Low-lying isomeric state in {sup 80}Ga from the {beta}{sup -} decay of {sup 80}Zn

A new level scheme was constructed for {sup 80}Ga which is significantly different from the one previously reported. The excitation energy of a new low-lying state recently reported in [2] was identified at 22.4 keV. Properties of the level scheme suggest that the ground state has spin J = 6 and the first excited state has spin J = 3. The spin assignments are in agreement with laser spectroscopy values previously measured. Our work provides the first evidence for the J = 6 being the ground state.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Nuclear Data Sheets for A=85

Evaluated experimental data are presented for 13 known nuclides of mass 85 (Zn, Ga, Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo). Since the previous 1990 evaluation of A=85, {sup 85}Zn, {sup 85}Ga, {sup 85}Ge and {sup 85}nuclides are newly added here. Excited state data for {sup 85}Se, {sup 85}Zr have become available from radioactive decay and in–beam γ–ray studies. New and improved high–spin data are available for {sup 85}Br, {sup 85}Kr, {sup 85}Rb, {sup 85}Y, {sup 85}Nb and {sup 85}Mo. New direct and precise measurement of atomic masses of {sup 85}Ge, {sup 85}As, {sup 85}Se, {sup 85}Br, {sup 85}Rb, {sup 85}Zr, {sup 85}Nb and {sup 85}Mo have greatly improved the landscape of β decay–Q values and separation energies in this mass region. In spite of extensive experimental work on the isobaric nuclei of this mass chain several deficiencies remain. No excited states are known in {sup 85}Zn, {sup 85}Ga, {sup 85}As. Only a few excited state are assigned in {sup 85}Ge from {sup 85}Ga β– decay. From radioactivity studies, the decay schemes of {sup 85}Zn and {sup 85}Mo are not known, and those for {sup 85}Ga, {sup 85}Ge, {sup 85}As and 10.9–s isomer of {sup 85}Zr are incomplete. Level lifetimes are not known for excited states in {sup 85}Se, {sup 85}Br, {sup 85}Nb and {sup 85}Mo. The {sup 85}Tc nuclide has not been detected in fragmentation experiments at GANIL, alluding to its unbound nature for proton emission. The {sup 85}Kr, {sup 85}Rb, {sup 85}Sr, and {sup 85}Y nuclides remain the most extensively studied from many different reactions and decays. The evaluation of A=85 nuclides has been done after a span of 23 years, thus includes an extensive amount of new data for almost each nuclide. This work supersedes the data for A=85 nuclides presented in earlier full NDS publication by J. Tepel in 1980Te04 and a later one published in an update mode by H. Sievers in 1991Si01.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Nuclear Data Sheets for A = 86

The experimental nuclear spectroscopic data for known nuclides of mass number 86 (Ga, Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo, Tc) have been evaluated and presented together with Adopted properties for levels and γ rays. New high-spin data are available for {sup 86}Se, {sup 86}Br, {sup 86}Kr, {sup 86}Sr, {sup 86}Y, {sup 86}Zr and {sup 86}Mo; and lifetime data for high-spin states in {sup 86}Y and {sup 86}Zr. No significant new data since the 2001 NDS for A=86 have been reported for {sup 86}Rb and {sup 86}Nb. No data are yet available for excited states in {sup 86}Ga and {sup 86}As. The decay scheme of radioactive {sup 86}Ge is unknown, while those for {sup 86}Ga, {sup 86}As, 47.4 min isomer of {sup 86}Y, {sup 86}Nb and {sup 86}Tc are deemed as incomplete. Isomerism in {sup 86}Nb remains unconfirmed. This work supersedes the data presented in the previous NDS evaluation of A=86 published by 2001Si43.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Nuclear Data Sheets for A=82☆

The evaluators present in this publication spectroscopic data and level schemes from radioactive decay and nuclear reactions studies for all isobars, Z=28(Ni) to Z=42(Mo), with mass number A=82. For {sup 82}Ni not much is known other than its identification. Most of the new data, i.e., after the last NDS (2003Tu03), are based on compilations included in XUNDL. Contributions of the various compilers in XUNDL are gratefully acknowledged.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2013

Nuclear Data Sheets for A = 75

The experimental nuclear spectroscopic data for known nuclides of mass number 75 (Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Kr, Rb, Sr) have been evaluated and presented together with Adopted properties for levels and γ rays. New high-spin data are available for {sup 75}Ga, and {sup 75}Rb; and lifetime data for high-spin states in {sup 75}Br and {sup 75}Kr. For ΔJ =1, M1+E2 transitions in two rotational bands in {sup 75}Kr, several B(E2)(W.u.) values are anomalously high, deviating by 2–3 σ values from currently accepted RUL(E2) = 300. In the opinion of the evaluators, there is need to remeasure level lifetimes and multipole mixing ratios in {sup 75}Kr to resolve this serious discrepancy. New precise single-particle transfer cross section data are available for {sup 75}Ga, {sup 75}Ge, {sup 75}As and {sup 75}Se from several different reactions (2009Ka06,2008Sc03); these data give information for occupancy of valence neutron orbitals in the ground states of target nuclides: {sup 76}Ge, {sup 76}Se and {sup 78}Se. No significant new data since the 1999 NDS for A = 75 have been reported for {sup 75}As and {sup 75}Se. No data are yet available for excited states in {sup 75}Co, {sup 75}Ni and {sup 75}Sr. For {sup 75}Fe, only the isotopic identification is made with one observed event. The radioactive decay schemes of {sup 75}Co and {sup 75}Ni are unknown while those for {sup 75}Rb and {sup 75}Sr are incomplete. This work supersedes the data presented in the previous NDS evaluation of A = 75 published by 1999Fa05.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Nuclear Data Sheets for A = 61

The evaluated spectroscopic data are presented for known nuclides of mass 61 (Sc,Ti,V,Cr,Mn,Fe,Co,Ni, Cu,Zn,Ga,Ge). Excited-state data are nonexistent for {sup 61}Sc, {sup 61}Ti, {sup 61}V, and {sup 61}Ge. Significant amounts of new data have been added since the previous NDS evaluation of A=61 nuclides (1999Bh04). {sup 61}Sc nuclide is now experimentally known, but without any knowledge of its half-life. The ground state half-lives of {sup 61}Ti and {sup 61}V are now determined. Excited-state data have become available for {sup 61}Cr, {sup 61}Mn and {sup 61}Ga, while for {sup 61}Ge, five excited states were erroneously assigned in the previous evaluation, these have been omitted here. Improved and extensive high-spin excitations are available for {sup 61}Fe, {sup 61}Cu and {sup 61}Zn, including several new superdeformed structures in {sup 61}Cu and {sup 61}Zn. Thermal neutron capture γ-ray data are available in detail from 2004Ra23. The radioactive decay schemes of {sup 61}Sc and {sup 61}Ti are not known, while those for {sup 61}V, {sup 61}Fe and {sup 61}Ge are poorly known. This work benefited from the earlier full evaluations of A=61 published by 1999Bh04, 1983Ek01 and 1975Au05 and the one published in an ‘update’ mode by 1992Zh31. The data and conclusions presented in the current work supersede those in all the previous evaluations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2013

Structure of {sup 81}Ga populated from the {beta}{sup -} decay of {sup 81}Zn

We report on the results of the {beta}-decay of {sup 81}Zn. The experiment was performed at the CERN ISOLDE facility in the framework of a systematic ultra-fast timing investigation of neutron-rich nuclei populated in the decay of Zn. The present analysis included {beta}-gated {gamma}-ray singles and {gamma}-{gamma} coincidences from the decay of {sup 81}Zn to {sup 81}Ga and leads to a new and much more extensive level scheme of {sup 81}Ga. A new half-life of {sup 81}Zn is provided.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2018

Nuclear Data Sheets for A=59☆

-- Abstract: Evaluated spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented for {sup 59}Sc, {sup 59}Ti, {sup 59}V, {sup 59}Cr, {sup 59}Mn, {sup 59}Fe, {sup 59}Co, {sup 59}Ni, {sup 59}Cu, {sup 59}Zn, {sup 59}Ga, and {sup 59}Ge. This evaluation for A=59 supersedes the earlier one by C. M. Baglin (2002Ba42) and updates for some nuclides in the ENSDF database. Highlights: of this evaluation are the following: In {sup 59}Fe, a new level at 568.45 keV (3/2{sup −}) has been added. This resolves a doublet at 570 keV, which was reflected in earlier evaluations (1983An22, 1993Ba85, 2002Ba42) and literature as well. Conflicting spin assignments for 2153.62 keV level of {sup 59}Co [9/2,13/2 in (α,pγ); (13/2) in ({sup 15}N,4nγ); 15/2 in (p,p′γ), (7/2{sup −}) in (n,n′γ)] exist in the literature and additional experimental work is needed to resolve the issue.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2012

Mode structure in the far field radiation of a leaky-wave multiple quantum well laser

The radiation patterns of a leaky-wave InGaAs/GaAs/InGaP laser are studied. In the subthreshold regime, several peaks are found, corresponding to the emission of fundamental and excited modes. The dependences of the amplitude, position and width of the peaks on the pump current are investigated and explained. (measurement of laser radiation parameters)

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2013

The influence of pairing correlations on the isospin symmetry breaking corrections of superallowed Fermi beta decays

Within the framework of quasi-particle random phase approximation, the isospin breaking correction of superallowed 0{sup +} {yields} 0{sup +} beta decay and unitarity of Cabibbo-Kobayashi-Maskawa mixing matrix have been investigated. The broken isotopic symmetry of nuclear part of Hamiltonian has been restored by Pyatov's method. The isospin symmetry breaking correction with pairing correlations has been compared with the previous results without pairing. The effect of pairing interactions has been examined for nine superallowed Fermi beta decays; their parent nuclei are {sup 26}Al, {sup 34}Cl, {sup 38}K, {sup 42}Sc, {sup 46}V, {sup 50}Mn, {sup 54}Co, {sup 62}Ga, {sup 74}Rb.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2012

FIRST DETECTION OF KRYPTON AND XENON IN A WHITE DWARF

We report on the first detection of the noble gases krypton (Z = 36) and xenon (54) in a white dwarf. About 20 Kr VI- VII and Xe VI- VII lines were discovered in the ultraviolet spectrum of the hot DO-type white dwarf RE 0503-289. The observations, performed with the Far Ultraviolet Spectroscopic Explorer, also reveal highly ionized photospheric lines from other trans-iron group elements, namely Ga (31), Ge (32), As (33), Se (34), Mo (42), Sn (50), Te (52), and I (53), from which gallium and molybdenum are new discoveries in white dwarfs, too. For Kr and Xe, we performed an NLTE analysis and derived mass fractions of log Kr = -4.3 {+-} 0.5 and log Xe = -4.2 {+-} 0.6, corresponding to an enrichment by factors of 450 and 3800, respectively, relative to the Sun. The origin of the large overabundances is unclear. We discuss the roles of neutron-capture nucleosynthesis in the precursor star and radiation-driven diffusion. It is possible that diffusion is insignificant and that the observed metal abundances constrain the evolutionary history of the star. Its hydrogen deficiency may be the consequence of a late helium-shell flash or a binary white dwarf merger.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Gallium oxide semiconductor-based large volume ultrafast radiation hard spectroscopic scintillators

We report on the development of the first-ever inorganic radiation-hard moisture-insensitive large volume spectroscopic semiconductor-based scintillator with less than 2 ns decay time and light yields as high as 8000 ph/MeV. Despite extensive research into scintillator materials, the quest for an ideal scintillator combining ultrafast decay times (akin to BaF 2 and Yb-doped scintillators such as Lu 2 O 3 :Yb), high light yields (exceeding 2000 photons per MeV), spectroscopic capabilities, and exceptional radiation hardness remain unfulfilled. In this study, we demonstrate and report for the first time the viability of large-volume (up to 20 mm thickness) gallium oxide (β-Ga 2 O 3 ) semiconductor-based scintillators for applications requiring these properties. These β-Ga 2 O 3 scintillators were grown using the fast turnaround (~2 days) crucible-free optical float zone (FZ) technique. The high light yield and ultrafast decay time of these high-purity n-type semiconductors with free carrier concentration of 6 × 10 17 cm –3 are attributed to native defects, specifically oxygen vacancies (V O ) and gallium–oxygen vacancy pairs (V Ga –V O ), generated during optimized FZ growth. The ultrafast decay, along with high light yield, enables excellent timing resolution and high count rate detection for applications like time-of-flight positron emission tomography, physics experiments, and nuclear safety. The radiation hardness of these devices has been documented in a separate publication.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗