High spin isomers in129Snand130Sb

Abstract

In this work, microsecond isomers of the three neutron hole nuclei ${}^{129}\mathrm{Sn}$ and ${}^{130}\mathrm{Sb}$ were investigated. These nuclei were produced by the thermal neutron induced fission of ${}^{239}\mathrm{Pu}$ and ${}^{241}\mathrm{Pu}.$ The detection is based on time correlation between fission fragments selected by the LOHENGRIN spectrometer at ILL (Grenoble) and the $\ensuremath{\gamma}$ rays or conversion electrons from the isomers. The results include the identification of the $\ensuremath{\nu}{(h}_{11/2}^{\ensuremath{-}2}{d}_{3/2}^{\ensuremath{-}1}{)23/2}^{+}$ aligned isomer in the odd ${}^{129}\mathrm{Sn}$ and the $[\ensuremath{\pi}{g}_{7/2}\ensuremath{\nu}{(h}_{11/2}^{\ensuremath{-}2}{d}_{3/2}^{\ensuremath{-}1})]{13}^{+}$ isomer in the odd-odd ${}^{130}\mathrm{Sb}$ and their decay schemes. The interpretation of the level schemes is mainly based on a truncated shell model calculation using empirical two-body interactions. Several new $B(E2)$ strengths of isomeric transitions were measured and are discussed in the paper.