Abstract
A discriminating personnel dosimetry badge system is being developed using the TLD material CaSO4:Dy. The badge system is designed to eliminate effects due to the energy dependence of the TL response of this material for dosimetry measurements, while at the same time utilise this energy dependence to provide discrimination between gamma doses of different energies in a mixed radiation field. The system utilises a multi-element TLD badge containing three filter elements, which allow energy and radiation discrimination in the badge. These filters are designed as follows: (a) a beta shield to filter out 97% of the incident betas; (b) a gamma energy compensation filter to allow direct gamma deep dose determination for photons in the range 15 to 662 keV; and (c) a bias filter to enhance the overall energy discrimination of the badge system for the case of mixed radiation exposures. Doses recorded by the TL element under each filter are compared with the total dose recorded under an open window. Intercomparisons of recorded doses from these four areas then allow both beta-gamma discrimination and gamma energy discrimination. The systems's calibrated response to 137Cs gamma photons and to different NBS qualities of X and fluorescence radiations, as well as to 90Sr-90Y beta radiation, is presented in this paper. Based on these calibrated results the badge system's readout interpretation under theoretical situations of mixed beta-gamma and mixed energy radiation exposure is presented.