CIPM MRA COMPARISON REPORTS
SUPPLEMENTARY COMPARISON
EURAMET.RI(I)-S19
Air kerma in Am-241 and Co-60 radiation protection beams
Published on 20/02/2026 - © 2026 L. Persson et al
Citation L. Persson et al 2026 CIPM MRA Comparison reports 06003
Authors
L. Persson Swedish Radiation Safety Authority (SSM) Sweden 
J. Lillhök Swedish Radiation Safety Authority (SSM) Sweden
N. A. Cornejo Díaz Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT) Spain
M. Kelly National Physical Laboratory (NPL) United Kingdom
E. L. Hansen Norwegian Radiation and Nuclear Safety Authority (DSA) Norway
P. O. Hetland Norwegian Radiation and Nuclear Safety Authority (DSA) Norway
R. Nylund Radiation and Nuclear Safety Authority (STUK) Finland
J. Huikari Radiation and Nuclear Safety Authority (STUK) Finland
Abstract
A supplementary comparison of air kerma standards of five participating laboratories was carried out in 241 Am and 60 Co radiation beams at radiation protection level, from June 2024 to January 2025. Three of the participating laboratories are secondary standards laboratories (DSA, STUK, and SSM) and NPL and CIEMAT are primary standards laboratories, with NPL providing the reference values for the comparison. The comparison results are published in the BIPM key comparison database (KCDB) under the reference EURAMET.RI(I)-S19. The comparison was made indirectly using two ionization chambers as transfer instruments. The results are analysed and presented in terms of ratios of the calibration coefficients provided by the participants with respect to the comparison reference values.