Kinetic parameters of lithium tetraborate based TL materials

Lithium tetraborate (LTB) based thermoluminescent materials are attractive from the clinical and personnel dosimetry point of view because of their near tissue equivalence. Lithium tetraborate phosphors doped with different dopants like Copper (Cu), Silver (Ag), Phosphorus (P), Indium (In) and Manganese (Mn) or their combinations were synthesized by solid state route. Thermoluminescence (TL) glow curves and their emission spectra were recorded. The dosimetric characteristic of thermoluminescence materials mainly depend on the kinetic parameters like the trap depth, frequency factor and the order of kinetics. In this paper the kinetic parameters of lithium tetraborate based phosphors with different dopants were calculated using different standard methods namely variable heating rate method, initial rise method, peak shape method and isothermal decay method. A comparison was made for the trap depth obtained by the four methods for all the phosphors studied. It was found that the trap depth obtained by Isothermal decay method alone varies considerably for all the phosphors studied. The TL glow curves of LTB:Mn was generated from the estimated parameters by integrating the general order kinetic equations numerically using Adaptive Simpson Quadrature algorithm.