Thermoluminescence kinetic parameters of LiF:Mg,P

Abstract

Thermoluminescence (TL) kinetic analysis using Tm-Tstop,E−Tstop, peak shape and glow curve deconvolution methods have been carried out on the glow curves of LiF:Mg,P phosphor. Heating rate effects on the TL glow curve characteristics are also investigated. The TL glow curves acquired from the samples exposed to beta-radiation at a dose rate of 0.04 mGy/revolution and readout at heating rate of 2k/s exhibited two apparent peaks around 120℃ and 239℃. The Tm-Tstop analysis indicated that the sample’s glow curve is a superposition of at least four glow peaks at 120, 238, 262 and 284 °C. Glow curve deconvolution (GCD) also revealed four glow peaks, with peak temperatures similar to those from Tm−Tstop analysis, are required to provide best fit to the sample’s glow curves at all doses (FOM ≤ 3.8%). The activation energy (E) and order of kinetic (b) values of the glow peaks, were dose-independent. E values from GCD are 1.27, 1.01, 1.84 and 1.82 for peaks I, II, III and IV respectively, the corresponding values from E−Tstop are similar to the GCD values except for peak I. The b values from GCD analysis are 1.07, 1.04, 1.71 and 1.57. The E and b values obtained from using the peak shape method, are respectively 1.58 eV and 1.47 for the low temperature peak, and 1.53 eV and 2.34 for the high temperature peak. As the heating rate increases, the intensities of the glow peaks increase with their peak temperatures shifting toward the higher temperature. The pattern is discussed using two TL models.