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 (C₁ + C₃)/C₀ where C₀, C₁ and C ₃ are the concentrations of ²²²Rn, and the airborne concentrations of ²¹⁸Po and ²¹⁸Po (or ²¹⁴Bi), respectively. The studied Jacobi room model parameters included the ventilation rate λ_v, the aerosol attachment rate λ_a, the deposition rate λ_d^u of unattached progeny and the deposition rate λ_d^a 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. © 2011 Elsevier Ltd. All rights reserved.