Key comparison BIPM.RI(I)-K5 of the air-kerma standards of the KRISS, Korea and the BIPM in ¹³⁷Cs gamma radiation

Main text A new indirect comparison of the standards for air kerma of the Korea Research Institute of Standards and Science (KRISS), Korea, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 137 Cs radiation beam using the radiation protection facility of the International Atomic Energy Agency (IAEA) in Seibersdorf, Austria, in June 2025. The comparison result, based on the calibration coefficients for two transfer chambers and expressed as a ratio of the KRISS and the BIPM standards for air kerma, is 0.9992 with a combined standard uncertainty of 2.0 parts in 10 3 . The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database, to update the 2010 comparison result. 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 https://www.bipm.org/kcdb/ . 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).