CIPM MRA COMPARISON REPORTS
EURAMET.RI(I)-K5.2
Air kerma in Cs-137 radiation protection beams
Published on 20/02/2026 - © 2026 L. Persson et al
Citation L. Persson et al 2026 CIPM MRA Comparison reports
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
EL Hansen Norwegian Radiation and Nuclear Safety Authority (DSA) Norway
PO 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 key comparison of air kerma standards of five participating laboratories was carried out in 137 Cs 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 CIEMAT acting as the linking laboratory to the BIPM key comparison, BIPM.RI(I)-K5. The comparison results are published in the BIPM key comparison database (KCDB) under the reference EURAMET.RI(I)-K5.2. The comparison was made indirectly using one ionization chamber as transfer instrument. The results are analysed and presented in terms of degrees of equivalence suitable for entry in the BIPM key comparison database.