A TL MODEL-BASED ON DEEP TRAPS COMPETITION

TL appears as a very complex phenomenon. However, some general feature s are widely presented by TL materials: low TL yields, non-linear grow th with dose (supralinearity or saturation), lower efficiency for high LET particles etc., which are not explained by the well-known classic al one-trap band model. In the past, the competition between TL traps and deep (thermally disconnected) traps was proposed in theoretical mo dels accounting for some specific TL features. Arguments are presented here for a more general role of deep traps, in order to get an overal l satisfying (at least qualitatively) description of the TL phenomenon either in the irradiation stage (TL or ESR) or in the heating one. A corresponding theoretical model is proposed. It is outlined that the c ompetition between TL and deep traps leads to spatial correlations bet ween electrons in TL traps and recombination centres (trapped holes). On the other hand, occurrence of recombination is taken into account a s well in the irradiation step as during the heating one. As a result, on a very simple basis, the model accounts for supralinear behaviour of TL output with dose, non-exponential shape of TL or ESR growth curv es, slight temperature shift of glow peaks with dose and scarceness of observed second-order kinetics.