International intercomparisons of integrating radon detectors at the NIRS radon chamber

Full text: International intercomparisons of integrating detectors were conducted at NIRS (National Institute of Radiological Science, Japan) with a 24.4 m3 inner volume radon chamber. During the first intercomparison (05.2007) 4 groups participated and in the second intercomparison (10.2007) 16 participants were involved from 4 and 10 countries, respectively. Various types of detector, like CR-39, PicoRad and E-Perm were used for this purpose. All the detectors were simultaneously exposed to radon gas in the radon calibration chamber under well controlled conditions of temperature and relative humidity as well as radon concentrations. During the first intercomparison, the participants inter-compared their detectors under 3 exposure conditions (low - 100 kBq h m-3, medium - 500 kBq h m-3 and high - 1000 kBq h m-3 radon exposition). One exposure (medium) condition was used in the second intercomparison. Radon concentration was monitored using AlphaGUARD radon monitor certified by PTB. Most of detectors showed a close correspondence with each other, compared to the radon level provided by the radon chamber. It seems that data qualities are unified among the participants. (author)