Evaluation of the 2014 EC measurement comparison on ¹³⁷Cs in air filters

In 2014, the Joint Research Centre organised an interlaboratory comparison of ¹³⁷Cs measurement in air filters. This paper describes the context of the European measurement comparisons, as well as the technical implementation. Furthermore, sample treatment and measurements performed by participating laboratories are discussed and finally the evaluation of comparison results is presented. The intercomparison results are such that 71 out of the 76 laboratories (i.e. 93.4%) reported values within ±33% range of the reference value. - Highlights: • 76 participants from Europe in the EC ILC on the determination of ¹³⁷Cs in air filters. • Spiked air filters prepared individually for each participant. • 93.4% of the laboratories reported within ±33% interval of the reference value. • 70% of the submitted results are compatible on the basis of the E_n numbers. • The problems encountered confirm a permanent need for such comparisons.