A Monte-Carlo study of the fading of TL and OSL signals in the presence of deep-level competitors

CONDUCTION BAND-VALENCE BAND THEORY OF TL AND OSL: EMPHASIS ON DELOCALIZED TRANSITIONS AND EXPLANATION ON SOME UNUSUAL EFFECTS

We discuss some unusual thermoluminescence (TL) and optically stimulated luminescence effects. We focus on luminescence due to transitions of electrons or holes through the conduction or valence band, respectively. We deal with non-linear dose dependence and non-monotonic dose dependence and also dose-rate effects sometimes reported. Also, is discussed the sensitisation of a sample due to the combined effect of irradiation and annealing, occurring in quartz samples and other materials. Another effect presented is the occurrence of anomalously high activation energies and frequency factors and its possible theoretical interpretation. Also, are considered the effects of anomalous fading and anomalous stability. Yet another phenomenon is concentration quenching. Here, the intensity of emitted TL depends non-monotonically on the concentration of the impurity responsible for the emission. The explanations given to these phenomena are based on the numerical solutions of the relevant sets of differential equations as well as approximate analytical treatment.