The particle size dependent attachment of radon daughters to a carrier aerosol.

Most of the airborne radon-222 daughters are attached to aerosol particles. An experimental set-up for measuring the radon daughter activity as a function of the aerosol particle size is described. An electrostatic classifier selects particles of a certain size range from the indoor or natural aerosol. An arrangement of a filter and an alpha detector registers the radioactivity of the particles. Simultaneously the aerosol concentration is measured by an aerosol electrometer which is upgraded for two particle concentrations.Most of the airborne radon-222 daughters are attached to aerosol particles. An experimental set-up for measuring the radon daughter activity as a function of the aerosol particle size is described. An electrostatic classifier selects particles of a certain size range from the indoor or natural aerosol. An arrangement of a filter and an alpha detector registers the radioactivity of the particles. Simultaneously the aerosol concentration is measured by an aerosol electrometer which is upgraded for low particle concentrations