Field spectroscopic method for the determination of the degree of equilibrium between radon 222 and its daughters in the atmosphere

After a short review of the significance of the equilibrium fraction between radon and its short lived decay products for working level determinations in uranium mines as well as for the aerosol dynamics in the atmosphere, the use of solid state track detectors for measuring this fraction is demonstrated: the concentration of RaA relative to RaC' obtained after etching a collimated cellulose nitrate film simply added to a field radiometer equipment has been found to practically coincide with the corresponding ratio simultaneously measured with a surface barrier silicon detector. The simplicity of the equipment and the properties of the plastic detectors recommend the method for the adverse uranium mine conditions