Investigation of Thermoluminescence Properties of Gamma- Irradiated Synthetic TL -Compound

Calcium sulphate doped by dysprosium (CaSO4:Dy) has been locally prepared under laboratory controlled condition. Two standard techniques were used during the course of this work to achieve the optimum concentration of the activator (Dy). The obtained samples were thermally treated to improve its sensitivity as well as its stability. The glow curves of the prepared CaSO4:Dy have been taken after gamma irradiation and show three glow peaks at about 140, 225 and 350 degree C. The main dosimetric glow peak is located at 225 degree C. . It is observed also that the dosimetry peak is shifted to lower direction by increasing the dopant concentration from 0.5% up to 3% by about 15 degree C. The experimental results show that the optimum concentration of Dy in CaSO4 could be achieved when 2% by Wt. of the dopant is added to the host lattice. Also maximum sensitization is obtained when the samples are thermally annealed at 600 degree C for 100 minutes. The prepared samples are also sensitized by high dose ?-irradiation (7 kGy) from 60Co source. The rate of fading of these TL detectors is 11% after storage for three months in ambient temperature. These results have been discussed in greater details