Comparison of the national standards of air kerma between the PTB and the CPHR for selected x-ray qualities used in radiation protection, diagnostic radiology and radiation therapy (COOMET.RI(I)-S4)

Abstract

The air kerma calibration coefficients of a set of four transfer ionization chambers and the air kerma-length product calibration coefficients for a set of two transfer pencil-type ionization chambers were compared at the PTB, Germany, and the CPHR, Cuba, for 15 selected radiation qualities as used in mammography, general diagnostic radiology, computed tomography, radiation therapy and radiation protection. The CPHR performed its measurements in the period January to September 2017 and the PTB before (November 2016) and after (December 2017) that period. The comparison results for the selected beam qualities expressed as the ratio of calibration coefficients were in the range (0.98-1.01) and mostly (12 out of 18) consistent within the relative standard uncertainty of the comparison which ranged between 0.6 % and 1 %. Five results were within the extended (k=2) standard uncertainty. One result deviated relatively by 1.9%. A possible reason for the larger deviation is discussed. The results are published in the Key Comparison Data Base (KCDB) of the BIPM as supplementary comparison COOMET.RI(I)-S4.Main textTo 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, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).