Optical absorption and photoluminescence spectra were measured in crystals which had been colored by using 5MeV electrons. The results showed that this type of irradiation reduced, to a much greater extent than did γ-rays, the production of complex aggregate defects as compared with F3+ and F2 centers. The laser-active F3+ centers could even be created preferentially instead of F2 centers, by decreasing the irradiation temperature.

Selective Production of Aggregate Centers in LiF Crystals by Ionizing Radiations. G.Baldacchini, E.De Nicola, G.Giubileo, F.Menchini, G.Messina, R.M.Montereali, A.Scacco: Nuclear Instruments and Methods in Physics Research B, 1998, 141[1-4], 542-6