Performance test for radon measuring instruments using radon chamber at PTB

An intercomparison on radon (222Rn) measuring instruments was carried out at the Physikalisch Technische Bundesanstalt, Germany (PTB). Two types of alpha track detectors based on a passive 222Rn-thoron (220Rn) discriminative measurement technique were used: these were the commercially available Raduet and Radopot detectors that were developed and calibrated by the National Institute of Radiological Sciences, Japan (NIRS). The 222Rn grab sampling and continuous measurement methods were also compared using the PTB pulse ionization chamber. The results using the passive detectors showed that there was a good agreement between the time-integrated 222Rn concentrations obtained from the Raduet detectors and the PTB pulse ionization chamber, as in the case with the Radopot detectors. In the grab sampling measurements, the agreement between the 222Rn concentrations measured using the NIRS gas storage ionization chamber and the PTB pulse ionization chamber was within 5% as in the case with the NIRS scintillation cell measurement. Similar to the measurements of the passive detectors and grab sampling, little distinct difference in the 222Rn concentration was observed for the NIRS continuous electrostatic collection monitor.

► Performance test for radon measuring instruments at PTB was carried out.
► NIRS passive detectors, grab sampling and continuous instrument were used.
► The radon concentrations obtained by NIRS agreed with those from PTB.