Key comparison BIPM.RI(I)-K6 of the standards for absorbed dose to water of the NIST, USA and BIPM in accelerator photon beams
Ronald E. Tosh, S Picard, D T. Burns, P Roger, Fred B. Bateman, Huaiyu H. Chen-Mayer
A comparison of the dosimetry for accelerator photon beams was carried out between the National Institute of Standards and Technology (NIST) and the Bureau International des Poids et Mesures (BIPM) in September and October 2010. The comparison was based on the determination of absorbed dose to water for two radiation qualities at the NIST. The comparison result, reported as a ratio of the NIST and the BIPM evaluations, is 1.004 at 6 MV and 0.996 at 18 MV, each with a combined standard uncertainty of 6 parts in 103. This result is the third in the on-going BIPM.RI(I)-K6 series of comparisons.