High-energy transitions in the decay of 132I

Abstract

A study of the high-energy gamma rays of 132I with a three-crystal pair spectrometer has disclosed the presence of several new transitions. In addition, it has permitted more precise energy assignments for the previously observed gamma rays. Gamma rays having energies greater than the pair production threshold were found at 1.141±0.009, 1.22±0.02, 1.282±0.008, 1.359±0.012, 1.393±0.008, 1.439±0.014, 1.716±0.017, 1.767±0.012, 1.914±0.009, 1.988±0.009, 2.076±0.016, 2.162±0.016, 2.222±0.016, 2.394±0.012, 2.55±0.04 and 2.68±0.04 MeV. The electron spectrum has been examined with a six-gap iron beta-ray spectrometer covering the energy range of 100–2200 keV. Electron lines were observed corresponding to transitions at 147.4±0.9, 263.0±0.9, 285.5±1.1, 523.0±1.2, 631.5±1.4, 669.0±1.2 (complex), 728.8±1.7, 773.8±1.6, 954.9±1.9 and 1395±8 keV. A careful study of the end-point region of the beta spectrum has shown thet the maximum energy beta ray of 132I is at 2118±15 keV.