Comparison of the standards for air kerma of the BEV and the BIPM for 137Cs gamma radiation

A direct comparison of the standards for air kerma of the Bundesamt fur Eich- und Vermessungswesen (BEV), Austria, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the Co-60 radiation beam of the BIPM in March 2009. The result, expressed as a ratio of the BEV and the BIPM standards for air kerma, is 1.0034 with a combined standard uncertainty of 2.1 x 10(-3). The result of the previous direct comparison in Co-60 gamma rays, made in 1995, was 1.0055 (25). The degrees of equivalence between the BEV and the other participants in the key comparison have been calculated and the results are presented in the form of a matrix. A graphical presentation is also given.