Update of the BIPM comparison BIPM.RI(II)-K1.¹³³Ba of activity measurements of the radionuclide ¹³³Ba to include the 2009 result of the IRA (Switzerland) and the 2012 results of the LNE-LNHB (France) and BEV (Austria)

Since 2009, 3 national metrology institutes (NMI) have submitted 3 samples of known activity of ¹³³Ba 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.Ba-133, to update their earlier result dating more than 15 years ago. The values of the activity submitted were between about 2 MBq and 3 MBq. There are now nine results in the BIPM.RI(II)-K1.Ba-133 comparison. The degrees of equivalence between each equivalent activity measured in the SIR and the key comparison reference value (KCRV) have been calculated and the results are given in the form of a table. A graphical presentation is also given. (authors)