Distribution of color centers around swift ion trajectories in lithium fluoride crystals

Abstract Radiation defect kinetics modeling is used to describe ion tracks in lithium fluoride crystals. According to the track geometry, suggested model takes into account diffusion currents of point defects and their drift in the temperature and elastic fields, caused by thermal spike. Due to the different dilatation signs of vacancies and interstitials, the induced stress field produces the opposite forces, squeezing out the interstitials, whereas the vacancies are rather confined. Resulting anion depletion in the track center can explain formation of the track core, which was observed with SAXS, chemical etching, AFM and other techniques, for heavy projectiles when the linear energy transfer exceeds a threshold of ~10 keV/nm. The anion interstitials can form aggregates, which were observed with VUV absorption spectroscopy and NMR studies, aside the track center.