Swelling and creation of color centers in MgF2 single crystals irradiated with energetic heavy ions

Single crystals of MgF2 were irradiated with different ions of specific energy between 1.4 and 11.1 MeV/u. Using UV–Vis absorption spectroscopy, the creation of color centers was analysed as a function of the ion fluence and energy loss. The concentration of single F- and F2-centers versus fluence exhibits a nonlinear evolution similar as in LiF. The creation efficiency of color centers and their thermal stability deduced from isochronal annealing experiments are discussed in terms of aggregation as well as recombination of electron and hole centers. In addition, profilometry measurements were performed quantifying ion-induced volume changes as a function of the beam parameters.