LUMINESCENCE OF COLOR CENTERS IN MgF_2 CRYSTALS

摘要

The effects of gamma irradiation(<=10~7 Gy) and subsequent thermal annealing on the concentration of color and emission centers in MgF_2 crystals are studied. The photoluminescence spectra of the crystals are found to contain bands around 420,460,550,and 620 nm, with the respective excitation bands peaked at 370,320,410,and 480 nm.The 420-nm emission is assigned to M(C_2h) centers, the 460-nm emission to M(D_2h) centers, and the 530-nm emission to M(C_I) centers. Since both the 480-nm absorption band and the 620-nm photoluminescence band arise at fairly high gamma doses and also when a high concentration of M centers is accumulated through the thermal transformation of radiation-induced centers, we suppose that these bands are related to R or more complex centers.