Modeling of defect accumulation in lithium fluoride crystals under irradiation with swift ions

In many materials electronic excitations created around the trajectories of swift ions result in defect creation. Experimental observations often yield information on integral damage effects. The presented approach suggests a theoretical model to correlate integral damage results with microscopic effect produced by overlapping of individual single ion tracks. The model is applied to ion-beam induced defects in LiF crystals. Two aspects are treated separately viz. the ion-deposited energy distribution for a given fluence and the material response to the absorbed energy. The first problem is treated within the framework of stochastic superposition of ion tracks, taking into account the radial distribution of the energy transfer of a single ion. For lithium fluoride the creation of color centers is considered as the materials response. The dependence of the defect concentration on the absorbed energy is included in order to obtain the integral defect production.