Standardization and decay data of 153Sm

The activity concentration of a 153Sm solution was determined by 4πβ–γ coincidence measurements and by liquid scintillation counting (LSC). Both methods yielded results which differ by only 0.1%, the relative standard uncertainty being 0.1 and 0.2%, respectively. X-ray and gamma-ray emission probabilities of several transitions were measured; they were used to calculate beta transition probabilities. The emission probabilities of the 69.7 and the 103.2 keV gamma rays were found to be 0.0465±0.0005 and 0.2923±0.0018, respectively; and the half-life was found to be (46.274±0.007) h.