RADIATION-INDUCED DAMAGE AND ITS RECOVERY TO THERMOLUMINESCENCE SENSITIVITY OF LIF-MG, CU, P CRYSTAL

Lif:Mg, Cu, P polycrystal suffers a serious damage to its thermolumine scence (TL) sensitivity when exposed to high-level dose of Co-60 gamma rays. After an exposure up to 10(6) Gy, the relative TL response of t he peak (210 degrees C) per unit absorbed dose is only 1.40 x 10(-6) a s compared with that exposed to low dose. While the residual peak is e liminated by annealing at 400 degrees C, the thermoluminescent sensiti vity is about 14% of the original one for a test dose of 0.01 Gy. High temperature annealing procedures have been investigated to remove the influence of radiation damage on its sensitivity at low dose. Results show that after annealing at 600 degrees C for 30 min, the TL sensiti vity of the samples exposed to high-level dose can be restored. The pr ocedure of thermal treatment is described in detail. A possible explan ation for the recovery is discussed.