Implications of new correction factors on primary air kerma standards inSUP60/SUPCo-beams

摘要

Comparisons of primary standards for air kerma in60Co-beams are re-analysed taking into account the recently developed formalism that defines uniquely the various correction factors and the development of analytic and Monte Carlo methods to quantify these corrections. After a brief historical review of air kerma comparisons and ion chamber calculations, the new corrections are applied in a re-analysis of previously published comparison data. An independent Monte Carlo verification of the analytic point-source non-uniformity correction factor is presented. The combination of new proposed correction factors imply that some national standards should increase by as much as 1 and that the global increase is of the order of 0.6.