Comparison of 14C liquid scintillation counting at NIST and NRC Canada

Abstract

An informal bilateral comparison of 14C liquid scintillation (LS) counting at the National Research Council of Canada (NRC) and the National Institute of Standards and Technology (NIST) has been completed. Two solutions, one containing 14C-labeled sodium benzoate and one containing 14C-labeled n-hexadecane, were measured at both laboratories. Despite observed LS cocktail instabilities, the two laboratories achieved accord in their standardizations of both solutions. At the conclusion of the comparison, the beta spectrum used for efficiency calculations was identified as inadequate and the data were reanalyzed with different inputs, improving accord.

Standardization of 64Cu activity

“…Kossert and Mougeot (2015) demonstrated the potential importance of screening and exchange corrections very clearly in the case of 63 Ni, and Kossert et al (2014) suggested they may also be important in the 64 Cu case. We have previously noted that when this problem arises, it is more pronounced at lower counting efficiencies (Bergeron et al, 2016), which is consistent with our current results.…”