ALPHA-SPECTROSCOPY ON CR-39 TRACK DETECTORS FOR THE DOSIMETRY OF RADON DAUGHTERS

Long-term radon daughter concentration detection is of great interest in lung dose studies. An automatic image analysis system to carry out alpha-spectroscopy by tracks analysis on CR-39 (allyl diglycol carbona te) detectors was developed. Identification and separation of Rn-222, Po-218, and Po-214 contributions to the alpha-tracks in CR-39 exposed inside an open dosimeter were possible using the system. The calibrati on of the dosimeters with regard to Po-218, and Po-214 was performed t hrough an exposure in the National Radiological Protection Board (U.K. ) radon chamber. In four houses, long-term Po-218 and Po-214 concentra tions were measured by means of open dosimeters; Rn-222 levels were si multaneously assessed with permeation dosimeters. Estimates of the equ ilibrium factor, F, were made using theoretical equations giving F val ues as a function of radon daughters to radon gas concentrations ratio s. Based on the most sensitive of those relations, F values varying be tween 0.2 and 0.5 were obtained, in good agreement with data recorded by an active Equilibrium Equivalent Concentration (EEC) detection inst rument used for comparison. Copyright (C) 1996 Elsevier Science Ltd.