Decay of 45 sec and 83 sec 136I isomers

Abstract The γ-ray spectra of iodine species rapidly isolated from fission have been studied using Ge(Li) and NaI(Tl) detectors and 4096 channel analyzers. A total of 17 γ-rays are attributed to the decay of 83 sec 136 I. Another species was observed which decayed with 45 sec half-life by emission of 197·3, 220, 370, 381·8, and 1313·3 keV γ-rays. The 1313·3 keV γ-ray, previously attributed only to the decay of 83 sec 136 I, was found to have a 45 sec component. This observation characterizes the 45 sec species as an isomer of 136 I. A decay scheme is constructed for 45 sec 136 I with levels at 1313·3, 1694·1, 1892·4, and 2262·4 keV. A partial decay scheme is proposed for 83 sec 136 I. The nature of the levels is discussed and the results are compared with those from previous decay scheme and nuclear excitation studies.