Dependence of electrostatic diffusion of Rn progeny on environmental parameters

In previous work it was established that electrostatic diffusion of Rn progeny attached to aerosols can be used for passive dosimetry by replacing the pump-filter assembly in an active dosimeter by an electret. In the present work, results are presented on the dependence of activity collected by an electret on aerosol concentration, aerosol diameter, attachment rate of Rn progeny to aerosols, unattached fraction of Rn progeny, and Rn progeny concentrations. The electrostatic flow rate of Rn progeny is defined and all relationships analyzed in terms of this flow rate. The electrostatic flow rate is found to be reasonably constant for 0.03 micron less than particle diameter less than 0.09 micron, unattached fraction of 218Po less than 0.40 and 70,000/cm3 less than aerosol concentration less than 180,000/cm3; experimentally obtained data outside these limits are too few to draw any definite conclusions. The results are useful from a practical point of view because typical U mine conditions are described by these limits.