title: Effects of air exchange property of passive-type radon-thoron discriminative detectors on performance of radon and thoron measurements.
abstract: Pairs of diffusion chambers with different air exchange rates are used in a large-scale survey to determine radon and thoron, separately. When they are enclosed in radon-proof bags for keeping after the exposure, since radon does not escape out immediately from the low-diffusion chamber, it leads to further exposure in the bags and disturbs the estimation of radon and thoron concentrations. In this study, the effects of the different air exchange properties of the radon-thoron discriminative detectors with CR-39 chips on the estimations of radon and thoron concentrations were investigated. The commercially available and frequently used detectors, Raduet, are examined in this study. The result shows that radon escapes out in 10 h. When degassing is not enough after the exposure in a calibration experiment or high-background radiation area, the residual radon causes the overestimation of the radon concentration and increase in the uncertainty in the thoron concentration, i.e. a low-performance quality of radon and thoron measurements.
authors.affiliation: Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan. ys-omori@nirs.go.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Omori
authors.forename: M
authors.initials: M
authors.lastname: Janik
authors.forename: A
authors.initials: A
authors.lastname: Sorimachi
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: S
authors.initials: S
authors.lastname: Tokonami
mesh_terms: D000388:Air; D000396:Air Pollutants, Radioactive / Q000032:analysis*; D016902:Air Pollution, Indoor; D002138:Calibration; D004058:Diffusion; D004781:Environmental Exposure; D004867:Equipment Design; D015233:Models, Statistical; D011092:Polyethylene Glycols; D011834:Radiation Monitoring / Q000379:methods*; D011874:Radiometry / Q000379:methods; D011886:Radon / Q000032:analysis*; D017687:Radon Daughters / Q000032:analysis; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D000396:Air Pollutants, Radioactive; D017687:Radon Daughters; C028827:CR 39; D011092:Polyethylene Glycols; D011886:Radon