The internal alpha dose assessment (ICRP 65, 1994) depends on the value of the equilibrium factor F. This parameter is general- ly not measured and a mean conventional value ranging between 0.4 and 0.6 is assumed, possibly leading to a significant bias in the dose assessments. In this paper, a method for the measurement of F is reported, based on the total aerosol sampling on filters and immediate gross beta counting of 214Pb and 214Bi activities. Measurements are interpreted according to a Raabe–Wrenn and Jacobi simplified room model, leading to an estimate of the individual airborne activities of short-lived radon daughters, the removal parameter and the equilibrium factor. The method was laboratory tested and validated and it is being qualified by field surveys in different indoor environmental conditions.
A simple approach to measure the radon equilibrium factor F from air filter gross beta counting
ARMAN, GIUSEPPINA MARIA;CACCIA, MASSIMO;CAVALLO, DOMENICO MARIA GUIDO;
2014-01-01
Abstract
The internal alpha dose assessment (ICRP 65, 1994) depends on the value of the equilibrium factor F. This parameter is general- ly not measured and a mean conventional value ranging between 0.4 and 0.6 is assumed, possibly leading to a significant bias in the dose assessments. In this paper, a method for the measurement of F is reported, based on the total aerosol sampling on filters and immediate gross beta counting of 214Pb and 214Bi activities. Measurements are interpreted according to a Raabe–Wrenn and Jacobi simplified room model, leading to an estimate of the individual airborne activities of short-lived radon daughters, the removal parameter and the equilibrium factor. The method was laboratory tested and validated and it is being qualified by field surveys in different indoor environmental conditions.
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