Dose dependence of thermoluminescence peaks

Abstract

The dependence on the excitation dose of the maximum thermoluminescence intensity as well as of the peak temperature are investigated theoretically. It is shown that certain irregularities of the dose dependences can be explained by assuming the existence of a trapping level, the transition into which competes with the retrapping and recombination of the free carriers. By numerical solution of the appropriate equations, it is demonstrated that the maximum thermoluminescence intensity may depend super- linearly on the excitation dose. The power of the dose dependence was found to be 2 under certain circumstances at low doses, and reached even higher values before saturation of the competing level. The maximum temperature sometimes behaved in an unusual way; namely, it increased with increasing dose. The relation between the area under a glow peak and its maximum intensity is also studied; it is shown that the latter can usually serve as a measure for the former. This finding is of practical impor- tance, especially in thermoluminescent dosimetry, since the evaluation of the maximum intensity is obviously more convenient than that of the area.