Stable and transient color centers in Gd3Ga5O12 crystals

The work is devoted to investigation of stable color centers (CC) that are created in Gd3Ga5O12 (GGG) crystals under irradiation with y-quanta (E=1.25 MeV, D=10(5) Gy) as well as transient CC created in the crystals under irradiation with pulsed electron beam (E=0.25 MeV, pulse duration 10 ns, fluence 10(12) cm(-2), time interval of registration 0-500 ns). On the basis of the performed study of optical absorption spectra of the as-grown and irradiated crystals it was established the correlation between a defect subsystem of as-grown crystals and a type of CC induced by radiation in the crystals. The role of Ca2+ dopant ions in the processes of CC formation is examined. Models of the stable and transient CC are proposed.