Retrospective radon progeny measurements through measurements of 210Po activities on glass objects using stacked LR 115 detectors

A stacked LR 115 detector consisting of two active layers was proposed for determining 210Po activity in glass surfaces after deposition of short-lived radon progeny. The sensitivities of both active layers were calculated. Two glass samples were exposed in a chamber to determine the experimental calibration factors for the radon gas and progeny, which were then compared with the theoretical calibration factors from simulations. The experimental and the simulated calibration factors for radon progeny agreed well. The discrepancy between the calibration factors for radon gas was due to a much higher equilibrium factor used in the experimental calibration than the nominal value assumed in the simulation. A mini-survey of contemporary and retrospective radon progeny concentrations was carried out at 10 residential sites. A relationship between contemporary and retrospective radon progeny concentrations was not readily observable.