60Co in cast steel matrix: A European interlaboratory comparison for the characterisation of new activity standards for calibration of gamma-ray spectrometers in metallurgy

Two series of activity standards of 60Co in cast steel matrix, developed for the calibration of gamma-ray spectrometry systems in the metallurgical sector, were characterised using a European interlaboratory comparison among twelve National Metrology Institutes and one international organisation. The first standard, consisting of 14 disc shaped samples, was cast from steel contaminated during production (“originally”), and the second, consisting of 15 similar discs, from artificially-contaminated (“spiked”) steel. The reference activity concentrations of 60Co in the cast steel standards were (1.077±0.019) Bq g−1 on 1 January 2013 12h00 UT and (1.483±0.022) Bq g−1 on 1 June 2013 12h00 UT, respectively.