title: An instrument for measuring the unattached fraction of radon progeny with etched track detectors.
abstract: To measure the unattached fraction of radon progeny, a new type of portable, low cost, reusable integrating monitor with etched track detector (CR-39) was developed. This monitor simultaneously gives the average equilibrium-equivalent concentrations of unattached (222)Rn progeny (EEC(Rn)(u)), attached (222)Rn progeny (EEC(Rn)(a)) and also (220)Rn progeny (EEC(Tn)). It was calculated, according to the detection efficiencies which were derived by the Monte Carlo method, that the lower detection limits for EEC(Rn)(u), EEC(Rn)(a) and EEC(Tn) are 0.03  Bq m(-3), 0.12  Bq m(-3) and 0.07 Bq m(-3), respectively for 24 h integrating sampling at a flow rate of 2.92  l min(-1). The validity of the new monitor was confirmed through a series of intercomparison experiments.
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Weihai
authors.initials: W
authors.lastname: Zhuo
authors.forename: Qiuju
authors.initials: Q
authors.lastname: Guo
authors.forename: Lu
authors.initials: L
authors.lastname: Guo
authors.forename: Bing
authors.initials: B
authors.lastname: Shang
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation*; D017687:Radon Daughters / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000396:Air Pollutants, Radioactive; D017687:Radon Daughters