Comparison of the standards for air kerma of the NPL and the BIPM for60Co γ rays

An indirect comparison of the standards for air kerma of the National Physical Laboratory (NPL), United Kingdom and of the Bureau International des Poids et Mesures (BIPM) was made in 60Co gamma radiation in September 2007. The comparison result, based on the calibration coefficients for two transfer chambers and expressed as a ratio of the NPL and the BIPM standards for air kerma, is 1.0011 (0.0038). The degrees of equivalence between the NPL 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. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section I, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).