Absolute transition rates in 188Ir

Abstract

Half-lives of several excited levels in 188Ir have been measured using an electron-electron delayed coincidence spectrometer. Active 188Pt sources were prepared from spallation products using the ISOLDE on-line mass separator facility at CERN. The following half-lives were obtained: T 1 2 (54.8 keV level) = 1.93 ± 0.10 nsec; T 1 2 (96.7 keV level) = 1.59 ± 0.12 nsec; T 1 2 (187.6 keV level) = 0.056±0.013 nsec; T 1 2 (195.1 keV level) = 0.051 ±0.010 nsec; T 1 2 (478.3 keV level) ≦ 0.15 nsec . The 54.8 keV transition was found to have an enhanced E2 transition probability indicating a collective character for this transition.