Effect of thermal annealing on scintillation properties of Ce:Gd2Y1Ga2.7Al2.3O12 under different atmosphere

Cerium-doped 1% Ce:Gd2Y1Ga2.7Al2.3O12(GYGAG) single crystal samples grown via Czochralski method were annealed under air, O-2 and N-2 atmospheres from 350 to 1400 degrees C. The X-ray excited luminescence spectra, energy spectra and UV as well as thermally stimulated luminescence (TSL) spectra were performed comparatively on as-grown'' and thermally annealed samples. It was found that the luminescence efficiency after annealing in air and O-2 was significantly enhanced compared to the non-annealed samples and this phenomenon was suggested to be caused by the existence of some oxygen vacancies in the Ce: GYGAG crystals. And the oxygen vacancies in the as-grown GYGAG crystals can be effectively eliminated by means of annealing in O-2 containing atmosphere without changing the luminescence mechanism. From the TSL curves before and after annealing, three traps within 77-650 K were found to be related to oxygen vacancies.