MRA calibration and measurement capabilities--radioactivity.

The practical realisation of the Mutual Recognition Arrangement relies on its two main Appendices, B and C. Appendix B relates to the equivalence of national measurement standards. The dissemination of these standards is achieved by the provision of physical standards and measurement services, where the associated measurement values are traceable to the SI. Appendix C specifies the quantities and ranges for which participating institutes recognise the validity of calibration and measurement certificates issued by other participating institutes and these are detailed in the database devoted to these standards and services, commonly referred to as calibration and measurement capabilities. Each participating institute has the opportunity to submit entries, via its Regional Metrology Organisation (RMO), to the database but, in order for users to be able to make informed choices, it is important that the data are entered to a common standard. The Joint Committee of the RMOs and the Bureau International des Poids et Mesures is responsible for the coordination of data provided by the RMOs. It is for individual RMOs to ensure the correctness of their own entries and to review and comment on those from others. This paper details that process and describes the various entries in the tables. It also addresses some of the remaining issues that still need to be resolved, in particular, the magnitudes of uncertainties and the need for supporting comparisons, both of which still present some significant problems.