Optical and scintillation properties of Dy3+:Y3Al5O12 and undoped Y3Al5O12 crystals grown in reduction atmosphere

Optical and scintillation properties of a 1.0‐mol% Dy‐doped yttrium aluminium garnet (YAG) grown under N2 atmosphere and undoped YAG crystals were investigated. Both crystals were grown by the Czochralski process. The one of the undoped YAG crystal was grown in an Ar + H2 (97:3) reducing atmosphere. Absorption peaks at 352 nm and 366 nm observed in 1.0‐mol% Dy‐doped YAG originated from 4f‐4f transition of Dy3+. In addition, the crystal showed sharp emission lines at near 482 nm and 584 nm under 352 nm UV and alpha‐ray excitation. The light output of Dy‐doped YAG was estimated to be approximately 20,000 photons/(5.5‐MeV alpha ray, 241Am). The scintillation decay time constants for Dy‐doped YAG crystal was around 400 ns and 40 ns. Undoped YAG crystals grown under Ar + H2(97:3) atmosphere showed absorption and excitation peak at 370 nm. A 400‐nm emission peak was observed under 370‐nm excitation. The light output of the crystal was also estimated to be 50,000 photons/(5.5‐MeV alpha ray). The scintillation decay time constants of the crystal were around 370 ns and 50 ns. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)