Primary Standardization of Eu-152 by 4 pi beta(LS) -gamma (NaI) coincidence counting and CIEMAT-NIST method

The 4 pi beta-gamma coincidence counting and CIEMAT/NIST liquid scintillation method were used in the standardization of a solution of Eu-152. In CIEMAT/NIST method, measurements were performed in a Liquid Scintillation Counter model Wallac 1414. In the 4 pi beta-gamma coincidence counting, the solution was standardized using a coincidence method with "beta-efficiency extrapolation". A simple 4 pi beta-gamma coincidence system was used, with acrylic scintillation cell coupled to two coincident photomultipliers at 180 degrees each other and NaI(Tl) detector. The activity concentrations obtained were 156.934 +/- 0.722 and 157.403 +/- 0.113 kBq/g, respectively, for CIEMAT/NIST and 4 pi beta-gamma coincidence counting measurement methods.