The importance of the beta spectrum calculation for accurate activity determination of 63 Ni by means of liquid scintillation counting

International audienceThe activity concentration of a Ni-63 solution was determined by means of two liquid scintillation counting techniques: the TDCR method and the CIEMAT/NIST efficiency tracing technique. The results of both methods are in excellent agreement, provided that the Ni-63 beta spectrum calculation accounts for the atomic exchange effect. Thus, new beta spectrum calculations resolve a discrepancy that has been found in previous analyses. The influence of the computed beta spectrum on the final uncertainty of the activity concentration is discussed