Properties of γ -decaying isomers and isomeric ratios in the Sn 100 region

J. Park et al.-- 10 pags., 10 figs., 2 tabs. -- Publisher's Note / Erratum: Phys. Rev. C 96, 049901 (2017)
Half-lives and energies of γ rays emitted in the decay of isomeric states of nuclei in the vicinity of the doubly magic Sn100 were measured in a decay spectroscopy experiment at Rikagaku Kenkyusho (The Institute of Physical and Chemical Research) of Japan Nishina Center. The measured half-lives, some with improved precision, are consistent with literature values. Three new results include a 55-keV E2γ ray from a new (4+) isomer with T1/2=0.23(6)μs in Rh92, a 44-keV E2γ ray from the (15+) isomer in Ag96, and T1/2(6+)=13(2) ns in Cd98. Shell-model calculations of electromagnetic transition strengths in the (p1/2,g9/2) model space agree with the experimental results. In addition, experimental isomeric ratios were compared to the theoretical predictions derived with an abrasion-ablation model and the sharp cutoff model. The results agreed within a factor of 2 for most isomers. From the nonobservation of time-delayed γ rays in Sn100, new constraints on the T1/2, γ-ray energy, and internal conversion coefficients are proposed for the hypothetical isomer in Sn100.
The authors would like to thank the personnel at the RIKEN Nishina Center for providing the exotic radioactive isotope beam with record intensities. This experiment was performed at RI Beam Factory operated by RIKEN Nishina Center and CNS, University of Tokyo.We acknowledge the EUROBALL Owners Committee for loaning the germanium detectors and the PreSpec Collaboration for the readout electronics of the cluster detectors of EURICA. Support for the WAS3ABi setup was provided by the Rare Isotope Science Project, funded by the Ministry of Education, Science and Technology (MEST) and National Research Foundation (NRF) of Korea, as well as KAKENHI (Grant No. 25247045) of Japan Society for the Promotion of Science (JSPS). The authors acknowledge the support of the DFG cluster of excellence “Origin and Structure of the Universe,” German BMBF under Contract No. 05P15PKFNA and the Spanish Ministerio de Economía y Competitividad via Project No. FPA2014-57196-C5-4-P. Part of the research was funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada and also supported by FJNSP LIA (French-Japanese International Associated Laboratory for Nuclear Structure Problems).