1 Modeling of defect accumulation in lithium fluoride crystals under irradiation with swift ions. M. V. Sorokin 1,* , K. Schwartz 2 , C. Trautmann 2,3 , A. Dauletbekova 4 , A.S. El-Said 5,6 1 National Research Centre 'Kurchatov Institute', Kurchatov Square 1, 123182 Moscow, Russia 2 GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt, Germany 3 Technische Universität Darmstadt, 64289 Darmstadt, Germany 4 L.N. Gumilyov Eurasian National University, 5, Munaitpassov Str., 010008 Astana, Kazakhstan 5 Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia 6 Nuclear and Radiation Physics Lab, Physics Department, Faculty of Science, Mansoura University, 35516 Mansoura, Egypt Abstract. 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. PACS: 61.80.Jh; 61.80.Az; 61.72.jn Keywords: ion irradiation, color centers, defect accumulation, absorbed energy 1. Introduction In various materials, in particular in insulators swift ions produce radiation damage around their trajectories [1-3]. Tracks of individual ions can be analysed by microscopic methods such as transmission electron microscopy (TEM), scanning force microscopy (SFM) or by other direct techniques analysing non-overlapping ions such as small angle x-ray spectroscopy (SAXS) [4-6]. However, many other techniques provide only integral values of the irradiated surface and track size information is deduced indirectly from fluence series. These indirect techniques include optical absorption spectroscopy, luminescence measurements, X-ray and Raman analysis, electron and nuclear magnetic spectrometry, phosphorus afterglow measurements [7] and many others. A simple model considering track overlapping effects was first suggested for elastic collision cascades [8] and later applied for swift ions [9-12]. This model assumes that an experimentally measured integral value, which characterizes the damage production, is proportional to the irradiated area i A of the sample surface according to         a A A i exp 1 (1) * Corresponding author, tel.: +7 495 517 46 89 e-mail: m40@lab2.ru