Environmental radioactivity measurement: intercomparison exercise

In a recent national intercomparison exercise, about 100 laboratories involved in making environmental radioactivity measurements were invited to analyse samples suppled by the National Physical Laboratory (NPL). In total, 70 samples were sent out with most laboratories confining themselves to gamma spectrometry measurements. The exercise was successful in terms of the number of participants and the data generated. For most participants in this simple exercise, the results were very satisfactory. There were, however, a few laboratories whose results gave cause for concern. A follow up meeting was held to discuss matters arising from the exercise and its report [1], including those which gave rise to problems. In the view of NPL, intercomparisons of this type should be carried out on a regular basis in support of Quality Assurance programmes.