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At least 19 records
All sourcesNASA NTRSDOE OSTI
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 OSTI2020

Activity Estimations for HSA Co-60 targets for Cycles 168A, 168B, and 169A Memo

67 HSA cobalt targets have been irradiated in the ATR, starting back on 2/10/15. Individual HSA cobalt targets may have been moved to different positions and irradiated at different times in the ATR. A tool called the Isotope Production and Activation tool (IPA tool) was developed to capture the changes for different irradiation conditions. The IPA tool uses cross section and flux data, cycle history data, and HSA experiment positioning data to estimate a range of specific activities for each of the HSA cobalt targets to generate SCALE/ORIGENS inputs for each target. The IPA tool also post-processes the results for use in tables and figures. The IPA tool derived results that can be independently verified using an acceptable alternative method. The memo contains the specific activity for all 67 HSA cobalt targets.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Benchmark Experiment of Dose Rate Distributions Around the Gamma Knife Medical Apparatus

Dose rate measurements around a gamma knife apparatus were performed by using an ionization chamber. Analyses have been performed by using the Monte Carlo code MCNP-5. The nuclear library used for the dose rate distribution of {sup 60}Co was MCPLIB04. The calculation model was prepared with a high degree of fidelity, such as the position of each Cobalt source and shielding materials. Comparisons between measured results and calculated ones were performed, and a very good agreement was observed. It is concluded that the Monte Carlo calculation method with its related nuclear data library is very effective for such a complicated radiation oncology apparatus.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Nuclear Data Sheets for A = 52

The nuclear structure data belonging to all nuclei with mass number A=52 have been compiled and evaluated using experimental nuclear reaction data and decay data available before July 10, 2015. This evaluaton supersedes the previous publication for this msss chain (2007Hu08, Nuclear Data Sheets 108, 773 (2007)). The data for the ε decay of {sup 52}Co (104 ms) and the ε decay of {sup 52}Ni (40.8 ms) are both incomplete, so new studies would be useful.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Half-life determination for {sup 108}Ag and {sup 110}Ag

In this work, the half-life of the short-lived silver radionuclides {sup 108}Ag and {sup 110}Ag were measured by following the activity of samples after they were irradiated in the IEA-R1 reactor. The results were then fitted using a non-paralizable dead time correction to the regular exponential decay and the individual half-life values obtained were then analyzed using both the Normalized Residuals and the Rajeval techniques, in order to reach the most exact and precise final values. To check the validity of dead-time correction, a second correction method was also employed by means of counting a long-lived {sup 60}Co radioactive source together with the samples as a livetime chronometer. The final half-live values obtained using both dead-time correction methods were in good agreement, showing that the correction was properly assessed. The results obtained are partially compatible with the literature values, but with a lower uncertainty, and allow a discussion on the last ENSDF compilations' values.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Ab initio calculations on the magnetic properties of transition metal complexes

We present a protocol for the ab initio determination of the magnetic properties of mono- and polynuclear transition metal compounds. First, we obtain the low lying electronic states by multireference methods. Then, we include spin-orbit coupling and an external magnetic field for the determination of zero-field splitting and g-tensors. For the polynuclear complexes the magnetic exchange coupling constants are determined by a modified complete active space self consistent field method. Based on the results of the ab initio calculations, magnetic data such as magnetic susceptibility or magnetization are simulated and compared to experimental data. The results obtained for the polynuclear complexes are further analysed by calculations on model complexes where part of the magnetic centers are substituted by diamagnetic ions. The methods are applied to different Co and Ni containing transition metal complexes.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Nuclear-level densities in the {sup 49}V and {sup 57}Co nuclei on the basis of evaporated-neutron spectra in (p, n) and (d, n) reactions

The spectra of neutrons from the reactions {sup 49}Ti(p, n){sup 49}V and {sup 57}Fe (p, n){sup 57}Co were measured in the range of proton energies between 8 and 11 MeV along with their counterparts from the reactions {sup 48}Ti(d, n){sup 49}V and {sup 56}Fe (d, n){sup 57}Co at the deuteron energies of 2.7 and 3.8 MeV. These measurements were conducted with the aid of a time-of-flight fast-neutron spectrometer on the basis of the EGP-15 pulsed tandem accelerator of the Institute for Physics and Power Engineering (IPPE, Obninsk). An analysis of measured data was performed within the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations based on the Hauser–Feshbach formalism of statistical theory were carried out with nuclear-level densities given by the generalized superfluid model of the nucleus, the backshifted Fermi-gas model, and the Gilbert–Cameron composite formula. The nuclear-level densities of {sup 49}V and {sup 57}Co and their energy dependences were determined. The results were discussed together with available experimental data and data recommended by model systematics.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2013

Development of deformation in the island of inversion at N=40

The A Asymptotically-Equal-To 60-70 mass region of neutron-rich nuclei with Z{<=} 28 presents several interesting properties when approaching N= 40. At this subshell closure a new region of deformation develops. From the experimental side, these nuclei can be populated by means of multi-nucleon and deep inelastic collisions. Recent results on the gamma-ray spectroscopy of the neutron-rich nuclei in this mass region are discussed. In particular, the evolution of the nuclear shape is studied in {sup 65,67}Co isotopes, populated by bombarding a {sup 238}U target with a 460 MeV {sup 70}Zn beam at the Legnaro National Laboratory. A shape-coexistence structure is observed in {sup 67}Co. The experimental results are interpreted within the shell model framework in a very large model space. These calculations are able to describe with good accuracy the excited states observed in {sup 65,67}Co, at the edge of the island of inversion at N=40.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Evaluating Photocatalysts Using Gamma Radiation

A large amount of attention has been given to photocatalysts using UV radiation as the source of excitation; however, little work has been done to study photocatalysis using higher energy excitation sources, such as gamma or x-rays. During excitation, the photocatalyst absorbs light to produce electron-hole pairs (excitons). These excitons can react with absorbed species to yield reactive radical species that can degrade compounds or induce redox (oxidation-reduction) reactions. Common examples of semiconductor photocatalysts include: TiO{sub 2}, ZnO, Fe{sub 2}O{sub 3}, ZrO{sub 2}, and SnS. This project was conducted to investigate the photocatalytic oxidation of iron using gamma irradiation and several different semiconductor photocatalysts. Photometric Measurements: Photometric determination of Fe{sup II} and Fe{sup III} were made using a Cary 60 UV-Vis Spectrometer over a range of 800 - 200 nm at a scan rate of 60 nm/sec. Ferric (Fe{sup III}) ions have no detectable UV-vis spectrum, thus the absence of a peak in iron-based samples was taken as evidence of Fe{sup III} formation. Solution Preparation: Iron II (Fe{sup II}) standards were made by dissolving FeCl{sub 2}.6H{sub 2}O in deionized water using a sonicator. A solution of 1,10- phenanthroline was made by adding 40 mg of 1,10-phenanthroline to 20 mL of deionized water and sonicating for 60 minutes until a clear solution was obtained. Gamma Radiation Tests: Irradiated samples were exposed to Co-60 gamma radiation (1.17 MeV gamma) at a dose rate of ∼1 x 10{sup 5} Rad/hr Co-60. All samples were irradiated in glass scintillation vials. The presence of 30 mg of SnS reduces the amount of Fe{sup II} in solutions under gamma irradiation relative to samples with no SnS added. Fe{sup II} concentration decreases as irradiation time increases. This effect is enhanced when SnS is present. Fe{sup II} appears to decrease linearly with time. We found that the addition of SnS semiconductor, when combined with gamma radiation, oxidized more Fe{sup II} in the FeCl{sub 2} solution than gamma radiation alone. This suggests that SnS can be used as a photocatalyst using gamma radiation as the excitation source, although more detailed experiments are needed to confirm this belief. The next phase of this project would be to refine the preliminary results by determining exact quantities of SnS semiconductor and gamma radiation that induce sufficient redox. Repeated experiments with more samples could also give more data points for a chance at more representative and accurate data with error bars and standard deviations. Also, other semiconductors could possibly be tested to see how their effect on redox chemistry compares to that of SnS. The scope of this project could also be extended to include other metal or organic solutions to see if similar redox could be obtained.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Analysis of SCALE Criticality and Sensitivity Calculations for Reflected HEU Cylinders

The SCALE code package offers multiple nuclear data libraries and sensitivity and uncertainty (S/U) methods supporting and derived from Monte Carlo (MC) transport. The CSAS and TSUNAMI-3D sequences use KENO MC, utilizing either continuous-energy (CE) cross sections or multigroup (MG) cross section libraries. TSUNAMI-3D has two CE calculational methods: the iterated fission probability (IFP) method, and the Contribution-Linked eigenvalue sensitivity/Uncertainty estimation via Tracklength importance CHaracterization (CLUTCH) method. Previous work has shown poor agreement between CLUTCH and confirmatory direct perturbation calculations in specific applications (e.g., fissionable and polyethylene reflectors). The HEU-MET-FAST-084 (HMF-084) International Criticality Safety Benchmark Evaluation Project evaluation consists of 27 cylindrical highly enriched uranium metal cores with 14 unique reflector materials of 0.5 and 1 in. thicknesses. Included in this list of reflector materials are natural uranium and polyethylene. This work utilized SCALE 6.2.4 models of the HMF-084 evaluation, with additional non-physical configurations to test both the MG bias and CLUTCH functionality across a variety of reflector material thicknesses. The evaluation’s use of concentric cylinders allowed for examination of several MG self-shielding methods: infinite homogenous, cylindrical, and spherical. The results indicate that the use of polyethylene reflectors with CLUTCH is not fundamentally impossible but sensitive to geometry. The poor performance of CLUTCH with fissionable reflectors was reaffirmed. The 2 in. and greater polyethylene-reflected calculations demonstrate the necessity of using the 302-group library for fast systems. The nickel MG bias was substantial, as discussed in a companion paper, as were cobalt and iron.

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 OSTI2015

Nuclear Data Matters - The obvious case of a bad mixing ratio for 58 Co

We present results of modeled cross sections for neutron- and proton-induced reactions leading to the final product nucleus 58 Co. In each case the gamma-cascade branching ratios given in the ENSDF database circa 2014 predict modeled nuclear cross sections leading to the ground and first excited metastable state that are incompatible with measured cross sections found in the NNDC experimental cross section database EXFOR. We show that exploring the uncertainty in the mixing ratio used to calculate the gamma-cascade branching ratios for the 53.15 keV 2 nd excited state leads to changes in the predicted partial cross sections by amounts that give good agreement with measured data.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2012

Statistical properties of excited nuclei in the mass range 47 Less-Than-Or-Slanted-Equal-To A Less-Than-Or-Slanted-Equal-To 59

Level densities and their energy dependences for nuclei in the mass range of 47 {<=} A {<=} 59 were determined from the results obtained by measuring neutron-evaporation spectra in respective (p, n) reactions. The spectra of neutrons originating from the (p, n) reactions on {sup 47}Ti, {sup 48}Ti, {sup 49}Ti, {sup 53}Cr, {sup 54}Cr, {sup 57}Fe, and {sup 59}Co nuclei were measured in the proton-energy range of 7-11 MeV. These measurements were performed with the aid of a fast-neutron spectrometer by the time-of-flight method over the base of the EGP-15 pulsed tandem accelerator installed at the Institute for Physics and Power Engineering (Obninsk, Russia). A high resolution of the spectrometer and its stability in the time of flight made it possible to identify reliably discrete low-lying levels along with the continuum part of neutron spectra. Our measured data were analyzed within the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations were performed with the aid of the Hauser-Feshbach formalismof statistical theory supplemented with the generalized model of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for nuclear level densities. Nuclear level densities for {sup 47}V, {sup 48}V, {sup 49}V, {sup 53}Mn, {sup 54}Mn, {sup 57}Co, and {sup 59}Ni and their energy dependences were determined. The results are discussed and compared with available experimental data and with recommendations of model-based systematics.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

NaI Measurements of Plutonium & Other Sources with the INL Coin

This report is a presentation for the NEOD training course at SNL. Its purpose is to summarize the effects of the INL coin on gamma ray spectra for 60 Co, 137 Cs, and plutonium. Spectra recorded with and without the INL Coin illustrate how transmission plays a role in the dose-ratio factors written on the coin.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

Wavelengths, transition probabilities, and oscillator strengths for M-shell transitions in Co-, Ni-, Cu-, Zn-, Ga-, Ge-, and Se-like Au ions

Wavelengths, transition probabilities, and oscillator strengths have been calculated for M-shell electric dipole transitions in Co-, Ni-, Cu-, Zn-, Ga-, Ge-, and Se-like Au ions. The fully relativistic multiconfiguration Dirac–Fock method, taking quantum electrodynamical effects and the Breit correction into account, was used in the calculations. Calculated energy levels of M-shell excited states for Cu-, Zn-, Ga-, Ge-, and Se-like Au ions from the method were compared with available theoretical and experimental results, and good agreement with them was achieved.

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 OSTI2014

Beta Decay Study of the T{sub z}=−2{sup 56}Zn Nucleus and the Determination of the Half-Lives of a Few fp-shell Nuclei

This paper concerns the experimental study of the β decay properties of few proton-rich fp-shell nuclei. The nuclei were produced at GANIL in fragmentation reactions, separated with the LISE spectrometer and stopped in an implantation detector surrounded by Ge detectors. The β-delayed gammas, β-delayed protons and the exotic β-delayed gamma-proton emission have been studied. Preliminary results are presented. The decay of the T{sub z}=−2 nucleus {sup 56}Zn has been studied in detail. Information from the β-delayed protons and β-delayed gammas has been used to deduce the decay scheme. The exotic beta-delayed gamma-proton decay has been observed for the first time in the fp-shell. The interpretation of the data was made possible thanks to the detailed knowledge of the mirror Charge Exchange (CE) process and the gamma de-excitation of the states in {sup 56}Co, the mirror nucleus of {sup 56}Cu.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗