Mixed-order and general-order kinetics applied to synthetic glow peaks and to peak 5 in LiF:Mg, Ti (TLD-100)

Abstract

Mixed order (MO) and general order (GO) kinetics has been applied to synthetic thermoluminescence glow peaks and to the shape of isolated peak 5 in LiF:Mg,Ti (TLD-100) following post-irradiation annealing at 165°C. We compare the peak shape parameters involved in MO analysis ( s, E and c/ n 0) to the peak shape parameters involved in GO analysis ( s, E and b) using computerised total glow peak shape analysis. The predicted correlation between b and c/ n 0, by the originators of mixed order kinetics, is confirmed for the synthetic glow peaks, but is only approximated for a real system of defects such as peak 5 in post-irradiation annealed TLD-100. Nonetheless, the peak shape predicted by mixed order kinetics is capable of yielding excellent fits to the experimental peak shape of peak 5. The values of E obtained from the fits are in fairly good agreement with the literature and vary smoothly as a function of the duration of the post-irradiation anneal, as does the parameter c/ n 0, the fraction of thermally disconnected traps. The use of mixed order kinetics is, therefore, a viable alternative to general order kinetics in the intermediate situation (1 < b < 2), due to its physical basis compared to the more empirical basis of general order kinetics.