Decay data of 123Tem

Abstract

Measurements of coincidences between conversion electrons of the 88 keV transition in the ¹²³Te^m decay and subsequent 159 keV quanta have been made with a 4πβ-γ coincidence system equipped with a pressurized proportional counter (PPC) in the beta channel. With ¹²³Te^m sources prepared for activity determination, a detection probability for conversion electrons, ϵ, very close to ϵ = 1 was achieved. The following data have been derived from the slope of a polynomial fit to n_βn_γ/n_c vs (1 − ϵ)/ϵ by varying ϵ by discrimination and taking into account the γ sensitivity of the PPC (n_β, n_γ, n_c are the counting rates in the β, γ and coincidence channel): the total conversion coefficient of the 159 keV transition α_t = 0.1895(13), the γ-ray emission probability of the 159 keV photons p = 0.8407(9). These data agree with the theoretically calculated values, and with less accurate values determined experimentally by other authors.