APPLICATION OF CAVITY THEORY TO THE RESPONSE OF VARIOUS TLDS TO CO-60GAMMAS DEGRADED IN WATER

Several types of thermoluminescent dosimeters (LiF:Mg,Ti, Al2O3:Mg,Y a nd CaF2:Mn) were irradiated at different depths in a water phantom pla ced at a distance of 2.5 m from a panoramic Co-60 source. Detectors we re encapsulated in Plexiglas holders with a wall thickness of 0.5 cm. Reference dosimetry was carried out using a Fricke dosimeter and an io nization chamber. The experimental data were compared with the predict ions of the general cavity theory for gamma ray spectra at different d epths of water. The suitability of parameters of the cavity theory pro posed by different authors was evaluated in the analysis of the experi mental results. The results show that there is no need for any modific ation to the original and simple Burlin expression which gives very go od agreement with the experimental values.