Analysis of intercomparison results for radon-thoron discriminative detector / 中华放射医学与防护杂志

ABSTRACT

Objective To increase the cumulative measurement level of 222 Rn and 220 Rn and ensure the accuracy and reliability of the measurement result . Methods By using improved 222 Rn-220 Rn discriminative detectors ( LD-P detectors) , the radon research group of National Institute for Radiological Protection Chinese Center for Disease Control and Prevention participated with the intercomparison organized by National Institute of Radiological Science ( NIRS) , Japan. Specifically, with the 222 Rn-220 Rn discriminative detectors being sent to Japan, the comparison was completed under different conditions in the 222 Rn chamber and 220 Rn chamber in NIRS. After exposure, the detectors were sent back to our laboratory for etching and analysis, and then measurement result were informed to NIRS. Finally, NIRS returned the exposure reference values of 222 Rn and 220 Rn to our laboratory. Results Under the conditions of high and low levels of 222 Rn, the relative percentage differences ( RPD ) between the measured values and the reference value provided by the NIRS were -12. 0％ and -11. 8％, respectively, while coefficients of variation ( COV) were 3. 0％ and 6. 2％, respectively. Under the conditions of high level and low levels of 220Rn, the relative percentage differences (RPD) between the measured value and the reference value provided by the NIRS were -0. 8％ and -8. 0％, respectively; coefficients of variation ( COV ) were 6. 7％ and 4. 5％, respectively. Conclusions This intercomparison result were categorized by NIRS ( PRD<10％) , with the satisfactory result of LD-P detectors available.