Final Report for BEV – 2010 / 01 / 14 Comparison of the standards for air kerma of the BEV and the BIPM for 137 Cs gamma radiation

A direct comparison of the standards for air kerma of the Bundesamt für Eichund Vermessungswesen (BEV), Austria, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the Cs radiation beam of the BIPM in March 2009. The result,expressed as ratios of the BEV and the BIPM standards for air kerma, is 1.0041 with a combined standard uncertainty of 3.1 × 10. The result of the earlier direct comparison in Cs γ rays, made in 1995, was 0.9961(28); taking into account the changes made recently to both standards, the 1995 result becomes 1.0035 (24), in agreement with the present comparison result.