Abstract
Neutron-activated sources of and both share the isomeric first-excited state in as a daughter product. From independent measurements of both decays, we have measured the shell and total internal-conversion coefficients, and , for the 39.8-keV transition, which de-excites that state in , to be 141.1(23) and 1428(13), respectively. When compared with Dirac-Fock calculations, our new results disagree with the version of the theory that ignores the -shell atomic vacancy, which is consistent with our conclusion drawn from a series of measurements on high multipolarity transitions in nuclei with higher . Calculations that include the atomic vacancy indicate that the transition actually has a small component with mixing ratio (5).
- Received 3 October 2018
DOI:https://doi.org/10.1103/PhysRevC.98.054321
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