A NEW APPROACH TO ESTIMATING THE EQUILIBRIUM FACTOR BETWEEN RADON ANDITS DAUGHTERS

The estimation of the radiation exposure of the public in living rooms requires long-term measurements of the potential alpha energy concent ration of radon daughters during periods of some months. Because such measurements are quite difficult to perform, in most cases the radon c oncentration is therefore measured, from which the potential alpha ene rgy concentration can be calculated assuming an appropriate equilibriu m factor. Equilibrium factors resulting from short-term measurements o f the radon daughter concentrations are not representative for longer periods of time. Long-term measurements by means of the difference met hod, using, for instance, bare and filtered solid state etched track d etectors, are characterised by an unsatisfactory uncertainty in the me asurement of the derived equilibrium factor. Therefore, a new approach is proposed to estimate the equilibrium factor based on the calculate d relationship between the equilibrium factor and the activity concent rations of the different radon decay products. In comparison with the common difference method this concept indicates an improvement, provid ed the activity concentration of Po-214 is detected separately.