Lattice defects in CaF2 and SrF2 after proton irradiation

The time differential perturbed angular distribution method (TDPAD) has been applied to investigate the electric field gradient produced by radiation induced defects in the cubic lattices of CaF2 and SrF2. In mixed crystals of the alkaline-earth difluorides CaF2 or SrF2 and the rare earth trifluorides PrF3, NdF3 or SmF3 the amplitudesA 22 exp in the TDPAD spectra strongly depend on the rare earth trifluoride concentration. From the fact that the observed amplitudes are well described by a simple statistical model the conclusion can be drawn that the defects produced in CaF2 and SrF2 after proton irradiation are F− interstitials.