CaF2:Dy kristalinin kinetik parametrelerinin termolüminesans metodlarla belirlenmesi

The field of thermoluminescence dosimetry has rapidly expanded during recent years. Especially in environmental and personnel monitoring applications the use of phosphors with low atomic numbers is to be recommended because their responses remain essentially constant through a large spectrum of energies ( from low- energy x-rays to high-energy y-rays). One of the commercial low-atomic number phosphors is CaF2:Dy. Up to now no information has been found on the kinetic parameters of glow curve of CaF2:Dy (TLD-200) dosimeter in literature. Therefore, this study was undertaken to provide detailed information about the glow curve and kinetic parameters of CaF2:Dy phosphor. In the course of this study, samples were first irradiated with '"Sr-^Y fi-isy source to produce sufficient concentration of defect centers or traps and then thermoluminescence measurements were made to obtain the glow curves. The obtained glow curves were then analyzed by CGCD computer package and other methods such as isothermal decay, peak shape t iiiand initial rise methods. The effects of post-annealing heating rate, dose rate and fading on the glow curve of TLD-200 crystal and its kinetic parameters are widely investigated; The results show that all these processes have great influences on the glow curves and kinetic parameters. One of the important findings of this work was the determination of the kinetic order of peak VI, which was found to be between 1.55 and 1.6. Other peaks were found to obey the first order kinetic. This study has produced significant results about thermoluminescence properties of TLD-200 (CaF2:Dy) dosimeter, that were not reported previously. Key Words : Thermoluminescence, CaF2:Dy, TLD-200, Kinetic Parameters.