Determination of gamma-ray emission probabilities in the decay of 235U and 231Th

Abstract

The emission probabilities for the most prominent γ-ray transitions in the energy range from 25 to 206 keV accompanying the decay of 235U and its radioactive daughter 231Th were determined using calibrated Si(Li)_and high purity Ge detectors. The results are: P γ (25.65) = (0.145 ± 0.003), P γ (84.16) = (0.066 ± 0.003), P γ (143.8) = (0.109 ± 0.002), P γ (163.4) = (0.050 ± 0.001), P γ (185.7) = (0.575 ± 0.009) , P γ (205.3) = (0.050 ± 0.002). The quoted uncertainties, corresponding to a 1σ confidence level, take into account random and systematic uncertainties.