Measurement of the potential alpha energy concentration in air by separate registration of the radon decay product 214-Po using nuclear track etched detectors

Long-term measurements of the activity concentration of 222Rn in air can be easily performed using a solid state nuclear track detector within a diffusion chamber. The radiation exposure of the human respiratory tract is, however, mainly characterised by the potential alpha energy concentration Wp of the radon daughters. The measurement of this quantity over the same period of time is very difficult. Some authors applied the double chamber method, using one detector within a chamber closed by a diffusion filter and another detector within an analogous chamber, but without the filter. The results found from the relationship between Wp and the activity concentration of both alpha active decay products (218Po and 214Po) depend strongly on the exposure conditions, e.g. on the equilibrium factor and the fraction of unattached radon daughters. The aim of our studies was to find a new approach to estimating the potential alpha energy concentration on the basis of its relation to the activity concentration of 214Po only. (author)