Study on shaped single crystal growth and scintillating properties of Bi‐doped rare‐earth garnets

Shaped single crystals of Bi:Gd 3 Ga 5 O 12 (Bi = 0.102, 0.126 and 0.141 mol.%) and Bi:Y 3 Ga 5 O 12 (Bi = 0.041, 0.047 and 0.061 mol.%) were grown by the micro‐pulling‐down method. Measured optical absorption spectra show an absorption band round 290 nm ascribed to the lowest energy 6s 2 →6s6p transition of Bi 3+ . Difference in the position of the emission spectra of Bi‐related bands in Gd 3 Ga 5 O 12 (470 nm) and Y 3 Ga 5 O 12 (314 nm) was explained by the lower local distortion of Bi polyhedron in Y 3 Ga 5 O 12 host leading to smaller Stokes shift of only 0.36 eV. Unsuitability of Bi‐doping in the Gd 3 Ga 5 O 12 host to get energy transfer from Gd 3+ towards Bi 3+ centers was concluded, while Bi‐doped Y 3 Ga 5 O 12 could compete against Bi 4 Ge 3 O 12 scintillator. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)