EXPLANATION OF THE SUPERLINEAR BEHAVIOR OF THERMOLUMINESCENCE BY CONSIDERING THE RESIDUAL HOLES IN THE RECOMBINATION CENTERS BEFORE IRRADIATION

A model is proposed to explain the superlinear growth of thermoluminescence, based on a consideration of competition both in excitation and during heating between occupation of traps and luminescence centres. Before excitation, it is assumed that a population of electrons no remains in the competing traps while the same number of holes is left in the luminescence centres. On this basis, an implicit expression is obtained for the area under a glow curve, from which several thermoluminescence response curves for different sets of parameters can be obtained. The results show that the area under a glow curve at low doses has a linear dose-dependence for a large no and has a quadratic dose-dependence for a small value of no. In the case of early saturation of the competing traps, the dose-dependence is more than quadratic.