Investigation of thermoluminescence properties of calcite

ABSTRACTInvestigation of ThermoluminescenceProperties of Calcite (CaCO3)GÜN EsenM.Sc., in Physics EngineeringSupervisor: Assist. Prof. Dr. R.Güler YILDIRIMFebruary 2006, 65 pagesThe thermoluminescence characteristics of calcite samples of annealedand unannealed has been studied that were beta irradiated at different dose levelsin this study. The additive dose (AD), variable heating rate (VHR), initial rise(IR), computer glow curves deconvolution (CGCD) and peak shape (PS) methodshave been used for the evolution of TL glow peaks. These methods were used todetermine the number of peaks and kinetic parameters (activation energy E,attempt-to-escape frequency factor s and kinetic orders b). The calcite samplesthat were collected from Gaziantep city exhibit two main TL peaks following βirradiation between the dose levels 0.9 Gy and 864 Gy. The results indicate thatkinetic parameters that obtained vary fairly from the different methods. The glowcurves of annealed and unannealed sample irradiated with beta dose show mainpeaks at (115 and 254 0C). The enhancement in TL sensitivity was found to bedepending on the annealing temperature and time. The measurement of the doseresponses and fading process are very useful in radiation dosimetry andarcheological dating. The dose response of all peaks have shown a similar pattern.First they follow strong linearity and then saturate at different dose levels. Afterthe storage at room temperature for four weeks, peak 1 was completelydisappeared from the glow curves, but peak 2 was not affected during this period.Peak 1 is reduced to typically 36% of its original value at the end of 2 hours and70% its original value at the end of 6.5 hours. The glow curve structure of calcitewas also studied by additive dose method in this study and it was observed that itsglow curve is the superposition of at least two first order glow peaks.Keywords: thermoluminescence, annealing, unannealing, kinetic parameters,calcite.