Characterization of isomers produced by the spontaneous fission of 252Cf with the VESPA setup

Abstract

Isomers produced by spontaneous fission of \( ^{252}\)Cf were measured with the VESPA setup, composed of \(\hbox {LaBr}_3\)(Ce) detectors for fast \(\gamma \)-ray spectroscopy and an ionization chamber for detecting fission fragments. Identification of the isomers was derived from fission fragment-\(\gamma \)-\(\gamma \) coincidences. This paper presents the half-lives of 41 isomeric states measured with this setup, from less than a nanosecond up to tens of microseconds. Short-lived isomers in \( ^{94}\)Rb, \( ^{108}\)Tc, and \( ^{147}\)Ce are reported for the first time. In addition to this half-life analysis, the isomers are used to develop and test a nuclear charge calibration of the ionization chamber.