Decay Study of ¹¹⁷In Isomer Pair

Abstract

High purity of a 117 In m and ' 17 In 6 isomer mixture was achieved by a two-step preparation, in which a 98.85% enriched 116 Cd target was irradiated with either thermal neutrons or 12 MeV deuterone and the Cd-fraction was purified in the first step, and then the 117 In-activities accompanying by the beta-decay of 117 Cd were collected. The chemical effect accompanying the internal conversion electron emission at the isomeric transition of 117 In m was utilized in order to separate 117 In g from the interfering isomer 1 ' 7 In m . All the 117 In-activities were complexed with EDTA, and 117 In 8 liberated from the complex at the IC decay of 1 " In m was extracted by an oxine-chloroform solution to obtain a 117 In g sample isolated from the isomer 117 In m . The half-lives of a 117 In isomer-pair were determined to be 116.1 + 0.2 min and 43.1 ± 0.2 min for the m-and g-states, respectively.