Report of the CCRI(II) supplementary international comparison of measurement of activity per unit mass of Cs-134 and Cs-137 in wheat flour (CCRI(II)-S13)

Main text A supplementary international comparison of measurement of activity per unit mass of Cs-134 and Cs-137 in wheat flour (CCRI(II)-S13) was carried out by CCRI in 2018. The matrix of the sample was wheat harvested in 2011 after the Fukushima Daiichi Nuclear Power Plant accident. No spiking was applied to the sample. Twelve institutes reported their results. Averages of the reported results and the associated uncertainties were obtained using the power-moderated mean. This report describes the supplementary comparison reference value, the degrees of equivalence of the results, the procedures of this comparison, and the sample preparation and measurements by the participants. Successful participation in this comparison by a laboratory may provide evidential support for Calibration and Measurement Capability (CMC) claims for Cs-134 and Cs-137 measured using the laboratory's method(s) used in the comparison or methods calibrated by those used for the comparison. 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).