Radon dosimetry using plastic nuclear track detectors

Although radon and its airborne daughter products are prevalent in our natural environment, they constitute a significant hazard only when concentrated in some enclosure such as a mine, cave, cellar, or house. This paper describes the nature of radon/daughter concentrations occurring in a variety of situations, the resultant biological hazard, and present methods used in the attempt to reduce man's exposure to harmful radiation. Many attempts to perfect environmental and occupational dosimetry have been made. Area monitoring methods are presently used, but can give only approximations of personal exposures. Several personal dosimeters employing track-etch, TLD, and photographic film detectors have been developed and are evaluated here on the basis of tests performed in working uranium-mine conditions. An improved passive track-etch dosimeter for personal use is proposed which has a measurement range of about 30–400 WLH with a 95% confidence interval of ∼25% for the accuracy of individual measurements in relatively stable mine air. The cellulose nitrate plastic used in these measurements is only moderately sensitive (E_c3.5. MeV) and performance can be improved by using a more sensitive detector. Some measurements of these dosimeters adapted to environmental use are also presented.