64Ga spin from β-γ(CP) correlation data and decay to 64Zn levels☆
Abstract
The decay of 2.6 min 64Ga produced by the reaction 64Zn(p, n)64Ga has been studied by Ge(Li) γ-ray spectroscopy, NaI(TI) crystals both singly and in coincidence, and β-γ(CP) correlation measurements. A transmission type of polarimeter was used in the correlation measurements to give good discrimination against lower energy γ-rays. The decay was found to populate excited states in 64Zn at 991.3, 1799.2, 1909.8, 2608.5, 3186.2, 3261.7, 3365.9 3425.0, 3795.0, 4453.5 keV, and possibly 3623 keV. The decay properties of these states were generally found to agree well with the (p, p′γ) work of Van Patter and co-workers. Beta-gamma (CP) correlation measurements were made on β rays in coincidence with strong ground state γ-ray transitions from the states at 3365.9 and 3425.0 keV. The combined asymmetry parameter of −1.00±0.05 strongly favours a spin of 0 for the 64Ga ground state; a spin of 1 would be possible only if the mixing into the 64Ga ground state involves a very large Coulomb matrix element of . Possible explanations of the unusualy large Coulomb matrix element (35 keV) between the analogue of the 64Zn ground state and the 64Ga ground state are discussed.
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Cited by (17)
Nuclear Data Sheets for A=64
2021, Nuclear Data SheetsThe evaluated experimental data are presented and evaluated for 13 known nuclides of mass 64 (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se). For each nuclide, the best values combining all available data are recommended for spectroscopic properties. No excited states have been identified in 64Ti, 64As, and 64Se. Only one excited state in 64V as an isomer, and three in 64Cr have been identified. Data for excited states in 64Mn, 64Fe, and 64Co remain limited. 64Ni, 64Cu, and 64Zn are the most studied nuclides through various reactions and decays, followed by 64Ga and 64Ge. In the opinion of the evaluators, there are several incomplete or discrepant aspects of the high-spin portion of the level scheme for 64Zn above ≈5 MeV excitation which need to be resolved in further experiments using large γ-detector arrays. The decay schemes of 64Ti β−, 64As ε and 64Se ε are unknown, while very little information is available for 64V β− and 64Cr β−. The decay schemes of 64Mn β−, 64Fe β−, 64Co β− and 64Ge ε are somewhat better known, but still considered incomplete by evaluators. The decay scheme of 64Ga ε decay is known in detail, however there is the possibility of additional levels populated above 4713 keV, as the Q(ε) value is 7171 keV. The β−, β+ and ε decay modes of 64Cu are well known, as this radionuclide is of great importance in applications, for example, as a dosimeter for neutron flux determination in nuclear reactors, and as a radiopharmaceutical for positron emission tomography (PET). This work supersedes earlier full evaluations of A=64 by 2007Si04, 1996Si12, 1991Si03, 1979Ha35 and 1974Au04.
Nuclear Data Sheets for A = 64
2007, Nuclear Data SheetsThe evaluated spectroscopic data are presented for known nuclides of mass 64 (V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Ga,Ge,As,Se). Excited-state data are nonexistent for 64V, 64Cr, 64As and 64Se. Except for half-lives, no other radioactive decay data are available for the decay of 64V, 64As and 64Se; and those for the decays of 64Cr, 64Mn, 64Fe, 64Co and 64Ge are not considered as definitive. There are several high-spin studies for 64Zn nuclide, but many inconsistencies are noted in this evaluation and complete details of data in these studies are generally lacking in the published literature. This work supersedes earlier full evaluations of A = 64 by 1996Si12, 1979Ha35, 1974Au04 and 1967Ve09; and a mid-strem evaluation by 1991Si03 published in an 'update' mode.
Nuclear Data Sheets for A = 64
1996, Nuclear Data SheetsAbstract:The evaluated spectroscopic data are presented for known nuclides of mass 64 (Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge). Excited-state data are nonexistent for64Mn and64Fe. Radioactive decay data for64Mn are not available and those for64Fe,64Co and64Ge are not considered definitive.
The following nuclides have not yet been identified but, amongst other nuclides, have been included in theoretical calculations:64Ca (92Ma60,91To03,91Hi10);64Cr (95Re20,95Ri05,95Au04);64As (95Au04);64Se (93Sh11).
The literature available up to June 25, 1996 has been consulted. This work supersedes earlier evaluations of A=64 published in Nuclear Data Sheets (91Si03,79Ha35,74Au04,67Ve09).
Cutoff Date:Literature available up to June 25, 1996 has been consulted.
General Policies and Organization of Material:See the January issue of Nuclear Data Sheets.
Acknowledgments:The evaluator thanks Alfredo Galindo-Uribarri at Chalk River for discussions and communicating results of his recent in-beam experiment on64Zn, prior to publication.
General Comments:The statistical analysis of γ-ray data and deduced level schemes is carried out through computer codes available at Isotopes Project, Berkeley and Nuclear Data Center, Brookhaven. The methodology and procedures for some of these codes are described by 86BrZQ and 86Br21. A general 3% uncertainty is assumed in quoted theoretical internal conversion coefficients taken mainly from 68Ha53.
The values of μ and Q are from compilation by 89Ra17, when available.
Nuclear data sheets update for A = 108
1991, Nuclear Data SheetsThe 1982 evaluation of A=108 (82Ha61) has been revised. New Level schemes were obtained for 108In, 108Sn.
A semiempirical intrinsic-germanium detector response for beta rays from 4 to 8 MeV
1980, Nuclear Instruments and MethodsA semiempirical Ge(HP) detector response function for electron having kinetic energies between 4 and 8 MeV is presented. This detector response provides a mechanism for the correction of beta spectra which were obtained with a beta spectrometer consisting of a hyperpure germanium detector mounted in the bore of a superconducting solenoid. While a simplified response function consisting of a full-energy peak and a flat low-energy tail was an adequate approximation for the response function at energies below 4 MeV, the response at higher beta-ray energies could not be suitably approximated with a flat, low-energy tail below the full-energy peak. A significant fraction of the response-function strength is concentrated in a region of several-MeV width, lying below and near the full-energy peak. This feature of the response arises primarily from the production and subsequent partial absorption of bremsstrahlung photons in the detector.
The true detector response is not yet known to high precision. The present simplified approximation to the true response is designed to allow parameter extraction (endpoint energies, etc.) from raw data without excessive computer execution time and memory being devoted to the generation of more detailed approximations to the true detector response.
A simple triangular approximation to the effect of bremsstrahlung absorption on the low-energy tail of the response function was adopted. Further details of the response were then determined by the study of spectra from 10 nuclei having endpoints above 5 MeV. Two of these nuclei have accurately known endpoint energies (64Ga, with E0 = 6154 keV, and 58Cu, with E0 = 7541 keV). Results from the analysis of spectra from these two nuclei, using the semiempirical response, are presented.
Nuclear data sheets for A = 64
1979, Nuclear Data SheetsNuclear structure data available through March 15, 1979, are evaluated, and adopted level and gamma properties are given. The bulk of the data is presented pictorially for easy comparison. Experimental details, references, comments, and additional data are given in the text. All drawings, tables, and comments are reproduced from the computerized Evaluated Nuclear Structure Data File (ENSDF). Any additions or corrections desired by the users should be addressed to the evaluators for maintenance and updating of the computer file.
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Work performed under the auspices of the U.S. Atomic Energy Commission.