Determination of track radii and relation to the electronic energy density deposited in swift heavy ion irradiated LiNbO₃

In this work, the morphology and size of ion tracks in x- and z-cut LiNbO₃ irradiated with 185 MeV Au ions was investigated using Rutherford backscattering spectrometry in channeling geometry (RBS/c), scanning and transmission electron microscopy (SEM/TEM) and small angle X-ray scattering (SAXS). By combining these methods, the tracks were identified to be amorphous surrounded by a crystalline LiNbO₃ matrix. It is shown that unambiguous radii of the amorphous tracks are obtained when the sources of error and uncertainties for each method are carefully taken into account. The radius of ion tracks depends on the electronic energy loss per ion and unit length and on the ion velocity. It is assumed that the electronic energy deposited per volume along the ion trajectory can consider both effects. By accurately determining the track radius and comparing with available literature data, a consistent agreement between track radii and energy density is empirically found.