A REVIEW OF DATA OBTAINED IN A SERIES OF RADIOACTIVITY MEASUREMENT INTERCOMPARISON EXERCISES IN THE UK - GAMMA-RAY EMITTERS 1989-1994

During the past 5 years, the National Physical Laboratory (NPL) has co nducted a series of four intercomparison exercises directed at the env ironmental radioactivity measurement community in the UK. In general, the results have been encouraging but some problems have been highligh ted, such as cascade summing and the sources of nuclear data. The inte rcomparisons are reviewed and the changes and improvements observed ov er time are discussed. The implications for the UK National Measuremen t Accreditation Service (NAMAS) are also addressed.