Spectrometer studies of the radiations of neutron deficient isotopes of cesium and of the E3 isomers, Xe^127m and Xe^125m

Abstract

Cesium isotopes produced by I¹²⁷(α, xn) type reactions in the 60-inch and 184-inch cyclotrons were studied in Geiger counters, a mass spectrometer, beta-ray spectrometers, a sodium iodide crystal scintillation spectrometer, and a gamma-gamma coincidence spectrometer. The mass assignment of 30-minute Cs¹³⁰ was verified. The 6.25-hour Cs¹²⁷ was shown to decay predominantly by electron capture but also by the emission of positrons of 1.063-Mev and 0.685-Mev energy. Prominent gamma rays of 125 and 406 kev are observed. Cs¹²⁷ exhibits branching decay to 75-second Xe^127m in about one disintegration in 10⁴. This isomer was isolated and studied in a scintillation spectrometer. E3 radiation of 175 kev connecting h_11/2 and d_5/2 levels is followed by 125-kev M1 radiation corresponding to a d_5/2-d_3/2 transition to the ground state. Forty-five minute Cs¹²⁵ is shown to decay predominantly by electron capture and also by the emission of positrons of 2.05-Mev energy. Other lower energy positron groups are present. A prominent gamma ray of 112 kev is observed. In one disintegration in about 10³, Cs¹²⁵ decays to a 55-second Xe^125m. This isomer emits gamma rays of 75 and 110 kev which are believed to be E3 h_11/2-d_5/2 and M1 d_5/2-d_3/2 transitions, respectively. An incomplete study of Cs¹²³ shows it to be a 6-minute positron emitter.