Estimation of EEC, unattached fraction and equilibrium factor for the assessment of radiological dose using pin-hole cup dosimeters and deposition based progeny sensors

High concentration of radon (Rn-222) thoron (Rn-220) and their decay products in environment may increase the risk of radiological exposure to the mankind. The Rn-222, Rn-220 concentration and their separate attached and unattached progeny concentration in units of EEC have been measured in the dwellings of Muktsar and Mansa districts of Punjab (India), using Pin-hole cup dosimeters and deposition based progeny sensors (DTPS/DRPS). The indoor Rn-222 and Rn-220 concentration was found to vary from 21 Bqm(-3) to 94 Bqm-3 and 17 Bqm-3 to 125 Bqm-3. The average EEC (attached + unattached) of Rn-222 and Rn-220 was 25 Bqm(-3) and 1.8 Bqm(-3). The equilibrium factor for Rn-222 and Rn-220 in studied area was 0.47 +/- 0.13 and 0.05 +/- 0.03. The equilibrium factor and unattached fraction of Rn-222 and Rn-220 has been calculated separately. Dose conversion factors (DCFs) of different models have been calculated from unattached fraction for the estimation of annual effective dose in the studied area. From the experimental data a correlation relationship has been observed between unattached fraction (f(p)(Rn)) and equilibrium factor (FRO. The present work also aims to evaluate an accurate expression among available expression in literature for the estimation of f(p)(Rn). (C) 2015 Elsevier Ltd. All rights reserved.