A review of data obtained in a series of radioactivity measurement intercomparison exercises in the UK: γ-ray emitters 1989–1994

During the past 5 years, the National Physical Laboratory (NPL) has conducted a series of four intercomparison exercises directed at the environmental radioactivity measurement community in the UK. In general, the results have been encouraging but some problems have been highlighted, such as cascade summing and the sources of nuclear data. The intercomparisons are reviewed and the changes and improvements observed over time are discussed. The implications for the UK National Measurement Accreditation Service (NAMAS) are also addressed.