A new look at the models of the superlinear dose dependence of thermoluminescence

Two types of model are usually employed for explaining the superlinearity (SL) of dose dependence of thermoluminescence (TL). One involves competition during excitation between trapping states, which causes the filling of the relevant trap or centre to be superlinear. The other model deals with competition during heating which may result in a strong SL, even if the filling of the trap and centre in question are linear with the dose. In the present work it is demonstrated that the two effects may occur in the same range in a model of one centre and two competing traps. The combined, very steep SL can thus be explained. In a model with one trap and two centres, TL follows approximately the filling of the active centre which is linear-superlinear-linear-saturation. Thus, in the case of two traps, SL results mainly from competition during heating whereas when two centres are involved, competition during excitation prevails.