Update of the BIPM comparison BIPM.RI(II)-K1.Co-60 of activity measurements of the radionuclide 60Co to include the 2011 result of the CNEA (Argentina), the 2012 results of the BARC (India) and the NRC (Canada), and the 2014 result of the NIM (China)

Since 2010, four national metrology institutes (NMI) have each submitted a sample of known activity of 60Co to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Co-60. The values of the activity submitted were between about 175 kBq and 1600 kBq. The primary standardization results for the CNEA, Argentina and the BARC, India replace their earlier result of 2003 and 2001, respectively. There are now seventeen results in the BIPM.RI(II)-K1.Co-60 comparison. The key comparison reference value (KCRV) has been updated using the power-moderated weighted mean. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text 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 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).