Dosimetric characteristics of muscovite mineral studied under different annealing conditions

Abstract

The annealing effect on the thermoluminescence (TL) characteristics of x-ray irradiated muscovite mineral relevant to dosimetry has been studied. For un-annealed and 473 K annealed samples an isolated TL peak has been observed at around 347 K; however, annealing at 573, 673 and 773 K two composite peaks have been recorded at around 347 and 408 K. Kinetic analysis reveals that there is a trap level at a depth of 0.71 eV, and due to annealing at 573 K (or above), a new trap level generates at 1.23 eV. The dosimetric characteristics, such as dose response, fading and reproducibility, have been studied in detail for all types of samples. The highest linear dose response has been observed from 10 to 2000 mGy in the 773 K annealed sample. Due to generation of the deep trap level, fading is found to reduce significantly just after annealing above 573 K. Reproducibility analysis shows that after 10 cycles of reuse the coefficient of variations in the results for 60, 180 and 1000 mGy dose irradiated 773 K annealed samples are found to be 1.78%, 1.37% and 1.58%, respectively. These analyses demand that after proper annealing muscovite shows important dosimetric features that are essentially required for a thermoluminescence dosimeter (TLD).