Explanation of the superlinear behaviour of thermoluminescence by considering the residual holes in the recombination centres 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 r 0 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 r 0 and has a quadratic dose-dependence for a small value of r 0 . In the case of early saturation of the competing traps, the dose-dependence is more than quadratic.