A diffusion chamber for passive separated measurements of radon/thoron concentration in dwellings

摘要

In this research, a passive diffusion chamber has been developed for separated measurement of radon and thoron. The chamber consists of two volumes which are separated by a fiber glass filter. Two lexan polycarbonate nuclear track detectors (film) are placed inside of the volumes to detect the alpha particles of radon/thorn and/or their progenies. Another lexan polycarbonate detector covered with an optimized thickness of an attenuator is placed outside of the chamber to measure only ~(212)Po which its concentration can be related to that of long-life thoron progeny, ~(212)Pb. The sensitivities have been measured by 2.06 and 0.053 [tracks cm~(-2)(kBq m~(-3) day)~(-1)] values for radon and thoron respectively inside of the chamber, and 7960 [tracks cm~(-2)(kBq m~(-3) day)~(-1)] value for thoron outside of the chamber. So the system can be successfully used for separated measurement of an extended range of radon/thoron concentrations in dwellings.