Luminescence of color centers in MgF2 crystals

The effects of gamma irradiation (less than or equal to 10(7) Gy) and subse quent thermal annealing on the concentration of color and emission centers in MgF2 crystals are studied. The photoluminescence spectra of the crystals are found to contain bands around 420, 460, 550, and 620 nm, with the resp ective excitation bands peaked at 370, 320, 410, and 480 nm. The 420-nm emi ssion is assigned to M(C-2h) centers, the 460-nm emission to M(D-2h) center s, and the 530-nm emission to M(C-I) centers. Since both the 480-nm absorpt ion band and the 620-nm photoluminescence band arise at fairly high gamma d oses and also when a high concentration of M centers is accumulated through the thermal transformation of radiation-induced centers, we suppose that t hese bands are related to R or more complex centers.