Dose dependence and dose-rate dependence of the optically stimulated luminescence signal

The expected behavior of the dose dependence of the optically stimulated lu minescence (OSL) signal has been studied using numerical simulation. A simp le model of one trapping state and one kind of recombination center is pres ented, and the sequence of sets of simultaneous differential equations gove rning the processes during excitation, relaxation, and light exposure are n umerically solved. With the choice of reasonable trapping and recombination parameters, it has been shown that a quadratic dose dependence of this eff ect results from the model when the irradiation stage starts with empty tra pping states. This may explain reports in the literature of an initial supr alinear dose dependence of OSL. It is also shown that within the same model , one can get an initial linear dose dependence of OSL if one starts with p artly filled traps. Also has been studied the influence of dose rate on the measured OSL signal for a constant total dose, and some effect has been se en for a certain dose-rate range. The similarities and dissimilarities of O SL as compared to thermoluminescence with respect to these phenomena are di scussed. (C) 2001 American Institute of Physics.