Beta-Gamma and Beta-Delayed Neutron-Gamma Decay of Neutron-Rich Copper Isotopes
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Korgul, A.↗
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Results for “copper isotopics”
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Measurement and microscopic description of odd–even staggering of charge radii of exotic copper isotopes
Nuclear charge radii globally scale with atomic mass number A as A 1/3 , and isotopes with an odd number of neutrons are usually slightly smaller in size than their even-neutron neighbours. This odd–even staggering, ubiquitous throughout the nuclear landscape1, varies with the number of protons and neutrons, and poses a substantial challenge for nuclear theory. Here, we report measurements of the charge radii of short-lived copper isotopes up to the very exotic 78 Cu (with proton number Z = 29 and neutron number N = 49), produced at only 20 ions s –1 , using the collinear resonance ionization spectroscopy method at the Isotope Mass Separator On-Line Device facility (ISOLDE) at CERN. We observe an unexpected reduction in the odd–even staggering for isotopes approaching the N = 50 shell gap. To describe the data, we applied models based on nuclear density functional theory and A-body valence-space in-medium similarity renormalization group theory. Through these comparisons, we demonstrate a relation between the global behaviour of charge radii and the saturation density of nuclear matter, and show that the local charge radii variations, which reflect the many-body polarization effects, naturally emerge from A-body calculations fitted to properties of A ≤ 4 nuclei.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Updates to Improve the Evaluated Nuclear Data of Copper Isotopes in the Resolved and Unresolved Resonance Regions
The evaluated nuclear data of the 63,65 Cu isotopes have been updated in the resolved and unresolved resonance energy regions with the goal of improving the fidelity between calculated and measured critical benchmarks. Particular focus was devoted to the 63 Cu(n, γ) cross sections because of their large sensitivity to the reactivity in the benchmark calculations. By focusing on these cross sections, the set of parameters in both resolved and unresolved resonance regions were fitted to available experimental data. The newly updated evaluations were compared to the currently available ENDF/B-VIII.0 evaluations in reactivity calculations for copper-sensitive integral benchmarks. An initial study of the sensitivity of the benchmarks to the angular distributions was performed, finding it necessary to describe the angular distributions more accurately above 100 keV. This investigation uncovered the need for more accurate data for the 63 Cu(n, γ) cross section above 100 keV. An increase in the capture cross section was found to improve agreement for the considered benchmarks.
07 ISOTOPE AND RADIATION SOURCES↗
Metal-binding amino acid ligands commonly found in metalloproteins differentially fractionate copper isotopes
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Corday R. Selden↗
Surface and material analytics based on Dresden-EBIS platform technology
Nowadays widely used mass spectrometry systems utilize energetic ions hitting a sample and sputter material from the surface of a specimen. The generated secondary ions are separated and detected with high mass resolution to determine the target materials constitution. Based on this principle, we present an alternative approach implementing a compact Electron Beam Ion Source (EBIS) in combination with a Liquid Metal Ion Source (LMIS). An LMIS can deliver heavy elements which generate high sputter yields on a target surface. More than 90% of this sputtered material consists of mono- and polyatomic neutrals. These particles are able to penetrate the magnetic field of an EBIS and they will be ionized within the electron beam. A broad spectrum of singly up to highly charged ions can be extracted depending on the operation conditions. Polyatomic ions will decay during the charge-up process. A standard bending magnet or a Wien filter is used to separate the different ion species due to their mass-to-charge ratio. Using different charge states of ions as it is common with EBIS it is also possible to resolve interfering charge-to-mass ratios of only singly charged ions. Different setups for the realization of feeding the electron beam with sputtered atoms of solids will be presented and discussed. As an example the analysis of a copper surface is used to show high-resolution spectra with low background noise. Individual copper isotopes and clusters with different isotope compositions can be resolved at equal atomic numbers. These results are a first step for the development of a new compact low-cost and high-resolution mass spectrometry system. In a more general context, the described technique demonstrates an efficient method for feeding an EBIS with atoms of nearly all solid elements from various solid target materials. The new straightforward design of the presented setup should be of high interest for a broad range of applications in materials research as well as for applications connected to analyzing the biosphere, hydrosphere, lithosphere, cosmosphere and technosphere.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Routine production of copper-64 using 11.7MeV protons
Reliable production of copper-64 ({sup 64}Cu) was achieved by irradiating enriched nickel-64 ({sup 64}Ni, >94.8%) in an IBA 18/9 cyclotron. Nickel-64 (19.1 {+-} 3.0 mg) was electroplated onto an Au disc (125{mu}m Multiplication-Sign 15mm). Targets were irradiated with 11.7 MeV protons for 2 hours at 40{mu}A. Copper isotopes ({sup 60,61,62,64}Cu) were separated from target nickel and cobalt isotopes ({sup 55,57,61}Co) using a single ion exchange column, eluted with varying concentration of low HCl alcohol solutions. The {sup 64}Ni target material was recovered and reused. The {sup 64}Cu production rate was 1.46{+-}0.3MBq/{mu}A.hr/mg{sup 64}Ni(n = 10) (with a maximum of 2.6GBq of {sup 64}Cu isolated after 2hr irradiation at 40uA. Radionuclidic purity of the {sup 64}Cu was 98.7 {+-} 1.6 % at end of separation. Cu content was < 6mg/L (n = 21). The specific activity of {sup 64}Cu was determined by ICP-MS and by titration with Diamsar to be 28.9{+-}13.0GBq/{mu}mol[0.70{+-}0.35Ci/{mu}mol]/({mu}A.hr/mg{sup 64}Ni)(n = 10) and 13.1{+-}12.0GBq/{mu}mol[0.35{+-}0.32Ci/{mu}mol]/({mu}A.hr/mg{sup 64}Ni)(n 9), respectively; which are in agreement, however, further work is required.
07 ISOTOPE AND RADIATION SOURCES↗
Contribution of Ryugu-like material to Earth’s volatile inventory by Cu and Zn isotopic analysis
We report initial analyses showed that asteroid Ryugu’s composition is close to CI (Ivuna-like) carbonaceous chondrites (CCs) – the chemically most primitive meteorites, characterized by near-solar abundances for most elements. However, some isotopic signatures (for example, Ti, Cr) overlap with other CC groups, so the details of the link between Ryugu and the CI chondrites are not yet fully clear. Here we show that Ryugu and CI chondrites have the same zinc and copper isotopic composition. As the various chondrite groups have very distinct Zn and Cu isotopic signatures, our results point at a common genetic heritage between Ryugu and CI chondrites, ruling out any affinity with other CC groups. Since Ryugu’s pristine samples match the solar elemental composition for many elements, their Zn and Cu isotopic compositions likely represent the best estimates of the solar composition. Earth’s mass-independent Zn isotopic composition is intermediate between Ryugu/CC and non-carbonaceous chondrites (NCs), suggesting a contribution of Ryugu-like material to Earth’s budgets of Zn and other moderately volatile elements.
58 GEOSCIENCES↗
NUCLEOSYNTHESIS IN THE OUTFLOWS ASSOCIATED WITH ACCRETION DISKS OF TYPE II COLLAPSARS
We investigate nucleosynthesis inside the outflows from gamma-ray burst (GRB) accretion disks formed by the Type II collapsars. In these collapsars, massive stars undergo core collapse to form a proto-neutron star initially, and a mild supernova (SN) explosion is driven. The SN ejecta lack momentum, and subsequently this newly formed neutron star gets transformed to a stellar mass black hole via massive fallback. The hydrodynamics and the nucleosynthesis in these accretion disks have been studied extensively in the past. Several heavy elements are synthesized in the disk, and much of these heavy elements are ejected from the disk via winds and outflows. We study nucleosynthesis in the outflows launched from these disks by using an adiabatic, spherically expanding outflow model, to understand which of these elements thus synthesized in the disk survive in the outflow. While studying this, we find that many new elements like isotopes of titanium, copper, zinc, etc., are present in the outflows. {sup 56}Ni is abundantly synthesized in most of the cases in the outflow, which implies that the outflows from these disks in a majority of cases will lead to an observable SN explosion. It is mainly present when outflow is considered from the He-rich, {sup 56}Ni/{sup 54}Fe-rich zones of the disks. However, outflow from the Si-rich zone of the disk remains rich in silicon. Although emission lines of many of these heavy elements have been observed in the X-ray afterglows of several GRBs by Chandra, BeppoSAX, XMM-Newton, etc., Swift seems to have not yet detected these lines.
79 ASTRONOMY AND ASTROPHYSICS↗
Finalizing the {sup 63}Cu and {sup 65}Cu Resonance Evaluations for the ENDF/B-VIII Release
The resolved resonance region evaluation for the only two natural isotopes of copper ({sup 63}Cu and {sup 65}Cu) was carried out at the Oak Ridge National Laboratory (ORNL) in support of the US Department of Energy (DOE) Nuclear Criticality Safety Program (NCSP). The particular interest in the isotope of copper arose because it was linked with poor performance of the Zeus series of integral benchmarks from the International Criticality Safety Benchmark Evaluation Project (ICSBEP). Good agreement between the calculated and experimentally measured values for the ICSBEP benchmarks is essential to the NCSP because the ICSBEP benchmarks are used for validation purposes of criticality safety calculations. The particular set of four Zeus experiments had a highly-enriched uranium core with a thick copper-reflector resulting in a large sensitivity of the criticality of these systems to the cross section of copper in the intermediate energy range. Sobes et al. presented the effect of the newly resolved resonance region evaluations for the two isotopes of copper on the Zeus integral benchmarks, as well as 23 other benchmarks from the ICSBEP during the 2016 ANS Annual Meeting. The results presented in Ref. were calculated with the ENDF/B-VII.1 cross section libraries used for all other materials. However, it is suggested that the resolved resonance region evaluations for the isotopes of copper should not be judged only on their performance in the integral benchmark calculations especially when the ENDF/B-VII.1 cross sections are used for all of the other isotopes. Three reasons are provided for this. First and foremost, a new evaluation is an assessment of the physics of the nucleus of the particular isotope, and the goal of an application agnostic nuclear data evaluation is to improve evaluation by fitting state-of-the art R-Matrix formalism to highly precise experimental cross section measurements. The improved performance in the integral benchmarks should only come as a consequence of the improvement in the physics of the evaluation. Secondly, there is some uncertainty in the nuclear data evaluation of the cross section of all isotopes, so there could be some error in evaluating another isotope used in calculating the integral benchmark experiment. Such an error may have been having a compensating effect, in combination with the previous evaluations for the isotopes of copper. Thirdly, with the two isotopes of copper proposed for inclusion in the upcoming release of the ENDF/B-VIII library, performance of the new resonance evaluation for copper should be evaluated based on the calculation of the integral benchmarks with all of the evaluations proposed for inclusion in the ENDF/B-VIII release. These benchmarking results using the ENDF/B-VIII evaluations as they converge closer to their final form will be presented at the conference. This summary stresses the importance of the physics of the evaluation and reviews some of the steps taken in finalizing a resolved resonance region evaluation. (authors)
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
A Flow-Through Reaction Cell that Couples Time - Resolved Analysis
A non-metallic flow-through reaction cell is described, designed for in situ time-resolved X-ray diffraction coupled with stable isotope analysis. The experimental setup allows the correlation of Cu isotope fractionation with changes in crystal structure during copper sulfide dissolution. This flow-through cell can be applied to many classes of fluid-mineral reactions that involve dissolution or ion exchange.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Benchmarking of the Updated Resolved Resonance Region Evaluations of Copper
A new resolved resonance region (RRR) evaluation for the two naturally occurring isotopes of copper, {sup 63}Cu and {sup 65}Cu was performed at Oak Ridge National Laboratory (ORNL), and the benchmarking results based on the four highly enriched uranium (HEU), intermediate spectrum, copper-reflected Zeus experiments were presented in June 2014. Since then, two significant updates to the evaluations have been performed: first, the data for the experimental measurement of the capture cross section between 220 keV and 300 keV were renormalized and the resonance parameters were refitted. Second, the angular distribution of elastic scattering initially reported in point-wise form in File 4 of the ENDF file format with high fidelity was significantly reduced in size to allow for better computer storage. Twenty-seven criticality safety benchmarks from the International Criticality Safety Benchmark Evaluation Project (ICSBEP) were calculated using these updated resolved resonance region evaluations for the two isotopes of copper. (authors)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NID Copper Sample Analysis
The current focal point of the nuclear physics program at PNNL is the MAJORANA DEMONSTRATOR, and the follow-on Tonne-Scale experiment, a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay (0νββ). This experiment requires the use of germanium isotopically enriched in 76Ge. The MAJORANA DEMONSTRATOR is a DOE and NSF funded project with a major science impact. The DEMONSTRATOR will utilize 76Ge from Russia, but for the Tonne-Scale experiment it is hoped that an alternate technology, possibly one under development at Nonlinear Ion Dynamics (NID), will be a viable, US-based, lower-cost source of separated material. Samples of separated material from NID require analysis to determine the isotopic distribution and impurities. DOE is funding NID through an SBIR grant for development of their separation technology for application to the Tonne-Scale experiment. The Environmental Molecular Sciences facility (EMSL), a DOE user facility at PNNL, has the required mass spectroscopy instruments for making isotopic measurements that are essential to the quality assurance for the MAJORANA DEMONSTRATOR and for the development of the future separation technology required for the Tonne-Scale experiment. A sample of isotopically separated copper was provided by NID to PNNL in January 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are reported here. A second sample of isotopically separated copper was provided by NID to PNNL in August 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are also reported here.
copper isotopics↗
Counting the number of correlated pairs in a nucleus
We suggest that the number of correlated nucleon pairs in an arbitrary nucleus can be estimated by counting the number of proton-neutron, proton-proton, and neutron-neutron pairs residing in a relative S state. We present numerical calculations of those amounts for the nuclei {sup 4}He, {sup 9}Be, {sup 12}C, {sup 27}Al, {sup 40}Ca, {sup 48}Ca, {sup 56}Fe, {sup 63}Cu, {sup 108}Ag, and {sup 197}Au. The results are used to predict the values of the ratios of the per-nucleon electron-nucleus inelastic scattering cross section to the deuteron in the kinematic regime where correlations dominate.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Finalizing the 63 Cu and 65 Cu Resonance Evaluations for the ENDF/B-VIII Release
The resolved resonance region evaluation for the only two natural isotopes of copper ( 63 Cu and 65 Cu) was carried out at the Oak Ridge National Laboratory (ORNL) in support of the US Department of Energy (DOE) Nuclear Criticality Safety Program (NCSP). The particular interest in the isotope of copper arose because it was linked with poor performance of the Zeus series of integral benchmarks from the International Criticality Safety Benchmark Evaluation Project (ICSBEP). Good agreement between the calculated and experimentally measured values for the ICSBEP benchmarks is essential to the NCSP because the ICSBEP benchmarks are used for validation purposes of criticality safety calculations.
07 ISOTOPE AND RADIATION SOURCES↗
Hydrogen Adsorption and Isotope Mixing on Copper-Functionalized Activated Carbons
Not Available
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Colloid Rates of Radionuclides in Cooling Water of the 120-GeV Proton Accelerator Facilities at Fermilab - Paper 58
Cooling water systems for high-energy accelerators are typically equipped with a deionizer to keep water pure for accelerator materials and to remove radionuclides for radioactivity control. Although the deionizers are expected to collect the entire radionuclides, more radioactivity than expected remains in the cooling water in typical cooling water operations at J-PARC and the Tsukuba Campus of High Energy Accelerator Research Organization (KEK), Japan. For example, specific activity of {sup 7}Be in the cooling water for magnetic horns at the J-PARC Neutrino Experimental Facility was observed to be comparable to the limit of {sup 7}Be activity for drain (30 Bq/mL) after enough deionization duration. Removing this activity from the cooling water is an important problem that must be solved before the water can be released into the environment. In our previous study, it was found that some radionuclides had weak retention on ion-exchange resins in the cooling water deionizer system for the K2K target and magnetic horns at the 12-GeV proton accelerator in KEK, Japan. Incomplete adsorption in the deionizer was attributed to colloid formation. Therefore, understanding the colloid formation of radionuclides in cooling water is important for understanding the activity remaining in the cooling water. Colloid formation in water under high-intensity radiation fields has been investigated by previous irradiation experiments. Under 120-GeV proton irradiation of Cu foils in water, it was found that the colloid formation rates of Mg, Mn, Co, Ni, and Cu isotopes and those of {sup 7}Be, {sup 24}Na, {sup 42}K, and {sup 43}K were approximately 30% and 1.8-3.9%, respectively. Sc, Cr, and Fe isotopes were missing from the water. In the photon irradiation of water in a Cu tube using Bremsstrahlung from an electron linear accelerator and a {sup 60}Co γ-ray source at Kyoto University Research Reactor Institute, we observed Cu colloid formation in consequence of the corrosion of Cu. It is possible that radionuclides attach to the colloids formed by the corrosion of accelerator materials and pass through the deionizer. To enhance the understanding of the behavior of radionuclides in cooling water in a high-energy accelerator environment, we investigated the colloid formation of radionuclides in cooling waters at the 120-GeV proton accelerator facilities at Fermilab, USA. We have already reported the previous results of specific activities of γemitting radionuclides and {sup 3}H in water samples collected from eight cooling water systems. Following the previous study, this paper is concerned with the measurement of colloid formation rates of radionuclides in cooling waters. (authors)
43 PARTICLE ACCELERATORS↗
A Nuclear Family: A Race for Peace
Episode 3 reveals how Y-12 helped win the Cold War.
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗