James-Birchall model

Then the unattached fraction was calculated in each measurement and was found to be between. 05 and. 15 without aerosol sources in the room and below. 05 in the presence of aerosol sources. The effective dose equivalent was computed with the Jacobi-Eisfeld model and with the James-Birchall model and was more related to the radon concentration than to the equilibrium equivalent radon concentration. On the basis of our analysis a constant conversion factor per unit radon concentration of 5.6 (nSv/h)/(Bq/m ) or 50 (ySv/y)/(Bq/m3) was estimated. 

The fraction of unattached daughters (fp), the equilibrium factor (F) and the activity median diameter (AMD) are plotted in Figure 6 for all the measurements. The AMD is derived from the aerosol measurements. These three parameters are important in the dosimetric models. At the top of Figure 6 the effective dose equivalent is plotted, computed with two models called the J-E (Jacobi-Eisfeld) and J-B (James-Birchall) models in the NEA-report (1983, table 2.9, linear interpolation between AMD=0.1 and 0.2 ym). The figure also shows the effective dose equivalent calculated from the equilibrium equivalent radon concentrations with the NEA dose conversion factor (NEA,1983, table 2.11). 

James, A.C., Greenhalgh, J.R., and A. Birchall, A Dosimetric Model for Tissues of the Human Respiratory Tract at Risk from Inhaled Radon and Radon Daughters - A Systematic Approach to Safety, Proc. 5th Cong. IRPA, Jerusalem 1980, Perg. Press, Oxford, vol 2, 1045-1048, (1980). 

Birchall, A., James, A.C., Jarvis, N.S., Bailey, M.R. and Dorrian, M-D., Implementation of the new ICRP human respiratory tract model LUDEP 1.0. Chilton, NRPB-R264. 

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