Shaped single crystal growth and scintillation properties of Bi:Gd3Ga5O12

Shaped single crystals of Bi:Gd3Ga5O12 (Bi=0.102, 0.126 and 0.141%) were grown by the modified micro-pulling-down method. Strong evaporation of Bi during single crystal growth leading to lower concentration in the obtained crystals was detected. Measured optical absorption spectra show an absorption band round 290 nm ascribed to the lowest energy 6s2→6s6p transition of Bi3+. In the radioluminescence spectra in the region of 440-560 nm an emission composed of two bands and depending on Bi concentration was found and completed by the decay kinetics measurements. Unsuitability of Bi-doping in the Gd3Ga5O12 host to get energy transfer from Gd3+ towards Bi3+ centers was concluded.