DECAY OF SR-89 AND THE EMISSION PROBABILITY OF THE 909.12 KEV GAMMA-RAY TRANSITION

Gamma-ray emission rates have been measured for highly pure sources of Sr-89. These sources were prepared with relative Sr-85 activity ratio s that ranged from less than 0.606% to undetectable, and had been prev iously standardized for radioactive concentration. Three such source m aterials were measured using Ge spectrometers, and the probability per decay of the 909.12 keV gamma ray was found to be 9.555 x 10(-5) with a relative expanded uncertainty of 1.26%. This result and other repor ted probabilities per decay have been evaluated according to the proto col of the International Atomic Energy Agency Coordinated Research Pro gram on the Measurement and Evaluation of X-ray and Gamma-ray Standard s for Detector Efficiency Calibration. This evaluation yielded a recom mended value of 9.559 x 10(-5) with a relative standard uncertainty 0. 47% for the probability per decay of the 909.12 keV gamma ray. (C) 199 8 Elsevier Science Ltd. All rights reserved.