The decay of 12.3 h 130gI, 9.2 min 1 30mI and 6.5 d 132Cs

Abstract

The decay of 12.3 h 130gI and 9.2 min 130mI has been investigated by βγ and γγ coincidence studies using a plastic scintillator and large size Ge(Li) detectors. In the decay of 130gI, three β-ray groups and 18 γ-transitions were observed. A decay scheme allowing placement of 13 of the emitted γ-rays has been constructed and the following excited levels of 130Xe deduced: 536.0 (2 +), 1122.0 (2 +), 1204.5 (4 +), 1632.8 (4 +), 1808.0 (4 +), 1944.0 (5 +), 2170.5 and 2362.0 (6 +) keV. The 9.2 min 130mI decays 84% by a highly converted isomeric transition to 130gI and 16% by independent β-branching to levels of 130Xe. Two β-ray groups and four γ-rays have been observed. A partial decay scheme of this isomer is suggested. The 536.0 (2 +) and 1122.0 (2 +) levels of 130Xe are populated directly by the two β-groups from 130mI. Extensive γγ coincidence measurements on 6.5 d 132Cs have also been carried out. A decay scheme is suggested which permits incorporation of all of the observed 12 γ-transitions. In the electron capture and positon decay of this isotope 132Xe is formed, the excited levels of which have been adduced to be at 667.5 (2 +), 1297.5 (2 +), 1440.0 (4 +), 1803.0 (2, 3) and 1985.5 (2) keV. The first three excited states in 132Ba at 464.5 (2 +), 1031.5 (2 +) and 1129.0 (4 +) keV are populated in the negaton decay of 132Cs.