Comparison of the standards for air kerma of the BEV and the BIPM for¹³⁷Cs gamma radiation

Abstract

A comparison of the standards for air kerma of the National Institute of Metrology of China and of the Bureau International des Poids et Mesures was carried out in 60 Co gamma radiation at the BIPM in December 2001. The ratio of the NIM and the BIPM standards for air kerma is 0.9992, with a combined standard uncertainty of 0.0018.The degrees of equivalence between the NIM and the other participants in the ongoing key comparison BIPM.RI(I)-K1 have been calculated and the results are presented in the form of a matrix. A graphical presentation is also given.

Key comparison BIPM.RI(I)-K1 of the air-kerma standards of the ININ, Mexico and the BIPM in60Co gamma radiation

“…The correction for stem scatter was assumed to be the same as for the BEV primary standard, both chambers being of the same type and manufacturer; the correction measured at the BEV was 0.9995 (0.0003) and is taken from [7].…”