Long-term determination of airborne radon progeny concentrations using LR 115 solid-state nuclear track detectors

This paper described the establishment of lognormal distributions for the Jacobi room model parameters with a view to improve an existing method for long-term passive measurements of the equilibrium factor using LR 115 solid-state nuclear track detectors, namely, through the proxy equilibrium factor (F-p) method. F-p is defined as (C-1 + C-3)/C-0 where C-0, C-1 and C-3 are the concentrations of Rn-222, and the airborne r..s, concentrations of Po-218 and (218)po (or (214)isi) respectively. The studied Jacobi room model parameters included the ventilation rate lambda(v), the aerosol attachment rate lambda(a), the deposition rate lambda(u)(d) of unattached progeny and the deposition rate lambda(d) of attached progeny. The lognormal distributions generated more realistic distributions for the equilibrium factor F and the unattached fraction f(p) of the potential alpha energy concentration, and a much tighter relationship between F and F-p, when compared with the traditionally used uniform distributions. With the new relationship between F and F-p, the accuracy of the F-p method to determine F from F-p is significantly improved. (C) 2011 Elsevier Ltd. All rights reserved.