Standardization and decay data of Sm-153

The activity concentration of a Sm-153 solution was determined by 4 pi beta -gamma coincidence measurements and by liquid scintillation counting (LSC). Both methods yielded results which differ by only 0.1%, the relative stand ard uncertainty being 0.1 and 0.2%, respectively. X-ray and gamma-ray emiss ion probabilities of several transitions were measured; they were used to c alculate beta transition probabilities. The emission probabilities of the 6 9.7 and the 103.2 keV gamma rays were found to be 0.0465 +/- 0.0005 and 0.2 923 +/- 0.0018, respectively; and the half-life was found to be (46.274 +/- 0.007) h. (C) 1999 Elsevier Science Ltd. All rights reserved.