Author/Authors :
Madcour, W. E. Atomic Energy Authority - Nuclear Research Centre (NRC) - Radiation Protection Department, Egypt , El-Kolaly, M. A. Atomic Energy Authority - Nuclear Research Centre (NRC) - Radiation Protection Department, Egypt , Hanaish, B. A. Atomic Energy Authority - Nuclear Research Centre (NRC) - Radiation Protection Department, Egypt , Abo-Zeid, Hosnia M. Ain Shames University - Faculty of Women for Arts, Science and Educational, Egypt , Afifi, Sofia Y. Nuclear Materials Authority, Egypt , Abd Al-Maksoud, Thanaa M. Ain Shames University - Faculty of Women for Arts, Science and Educational, Egypt
Abstract :
Thermoluminescence (TL) studies of some natural calcium fluoride (CaF2) are presented in this work. The glow curves of the materials under investigation show 4 main glow peaks. The third one (P3) at 180 °C is considered as dosimetry peak with calculated activation energy 1.5 eV. The optimum heat treatment annealing at 450 °C for 30 minutes is found to obtain maximum TL intensity with low zero dose response (i.e. B.G. of TLD). The dose response with the TL intensity (TL area at each glow peak) is evaluated and found linear at the beginning of build up with gamma radiation dose to certain limit, then start to show supralinear trend. The fading effect at ambient temperature up to 120 days storage time is evaluated. In the first few days high fading is noted and farther become less. For high temperature peaks this effect does not exceed 5%. It is also concluded that the peak shifts to higher direction by about 5oC due to storage for about 4 months. Also the heating rate effects as well as the grain size of the powder of the sample particles have been studied in some details.
Keywords :
Thermoluminescence , natural CaF2 , heat treatment , TL traps , activation energy.
