Thirty-two laboratories submitted 38 sets of passive detectors for the 2006 intercomparison. The exercise included three exposures to radon and its decay products at different equilibrium factors. After exposure, the detectors were returned to their originating laboratories for assessment.
Participants reported the estimated exposure for each detector before they were notified of the exposures given to the detectors. The results obtained by participating laboratories were classified according to the spread of results from detectors exposed together and by the difference between the mean result of each group and the actual exposure given.
Forty-seven per cent of the laboratories achieved the highest classification for accuracy, while 27% were in the lowest category. The proportion of laboratories achieving very good results was broadly in line with that seen in recent intercomparisons.