A computational model for the simulation of radiation-induced trap-filling in multicrystalline insulators

This paper presents a model that describes the radiation response of a polycrystalline material with different trap populations in the bulk material and on the crystallite surface. The model describes the free charge created by the impact of a high-energy particle as a pseudo-classical ideal gas, which spreads through the crystal according to a diffusion equation. The charges can recombine, be trapped in a bulk trap or be trapped on a crystal surface. The paper describes the assumptions behind the model, the differential equations they lead to and a numerical finite-differences method by which the equations can be solved. The model parameters and their correlation to real world parameters are discussed and possible refinements are discussed. The typical properties of the model and the scope of theoretical calculations that can be performed with it are demonstrated on a number of examples with a set of idealized parameters. In particular, the model shows a dependency of the linear radiation sensitivity on the energy of the incoming radiation particles. The model is applied to the simulation of growth curves, where saturation and superlinearity can be observed. The model has useful applications in the fields of electron spill resonance (ESR) dating and of luminescence dating. (C) 1997 Elsevier Science Ltd.