Comparison of the air kerma standards for 137Cs and 60Co gamma-ray beams between the IAEA and the NIST

Abstract

A comparison of the air kerma standards for 137Cs and 60Co gamma-ray beams was performed between the NIST and the IAEA. Two reference class ionization chambers owned by the IAEA were used as part of this comparison and were calibrated at each facility. The calibration coefficients, NK, were determined for both chambers and in both gamma-ray beams. The measurements were performed at the IAEA and NIST facilities starting in the fall of 2009 and were completed in 2010. The comparison ratio of the calibration coefficients for each chamber, NK,IAEA/NK,NIST, between the IAEA and NIST was 0.999 and 0.997 for the 137Cs and 60Co gamma-ray beams respectively. The relative standard uncertainty for each of these ratios is 0.5%.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 SIM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).