Decay of 2.1-min and 4.1-min ₁₃₂Sb Isomers and 2.3-min ¹³³Sb

Abstract

In an investigation of γ-ray spectra of Sb isotopes rapidly isolated from 235 U fission products, evidence was obtained for the existence of 2.1 and 4.1 min isomers of 132 Sb and for a 133 Sb half-life of 2.3 ± 0.3 min. Intense 7-rays with energies of 103.2, 697.4, and 974.6 keV were found to exhibit complex decay curves that could be resolved into 2.1 ± 0.3 and 4.1 ± 0.4 min components and were assigned to the decay of 132 Sb isomers. Other equally intense 7-rays at 1096.4, 1728.2, and 2751.7 keV showed half lives of 2.3 ± 0.2 min and, as they were found to have no coincidence relationships with the above three 7-rays, were assigned to 133 Sb decay. Observation of γ-γ coincidences permitted the assignment of the 989.3 keV 7-ray to the decay of 2.1 min 132 Sb, the 151.1 and 383.2 keV 7-rays to the decay of 4.