An indirect comparison of the standards for air kerma of the National Institute of Standards and Technology (NIST), USA, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in September 2011. The comparison result, based on the calibration coefficients for two transfer standards and expressed as a ratio of the NIST and the BIPM standards for air kerma, is 1.0039 with a combined standard uncertainty of 0.0034. The results are analysed and presented in terms of degrees of equivalence for entry in the BIPM key comparison database.
Pub Type: Journals
air kerma, BIPM, chamber, comparison, Co60