Positive hysteresis of Ce-doped GAGG scintillator

• 800 Gy gamma-ray was irradiated to Ce 1% and 3% doped GAGG crystals, Ce:YAG, Ce:LuAG, Pr:LuAG, and Ce:GAGG ceramic.
• Ce 1% doped GAGG crystal showed positive hysteresis.
• This is the first time to observe positive hysteresis in Ce-doped GAGG.
• In Ce 1% doped GAGG crystal, new excitation band was created around 60 nm after gamma-ray irradiation.

Positive hysteresis and radiation tolerance to high-dose radiation exposure were investigated for Ce 1% and 3% doped Gd3(Al, Ga)5O12 (Ce:GAGG) crystal scintillator on comparison with other garnet scintillators such Ce:YAG, Ce:LuAG, Pr:LuAG, and ceramic Ce:GAGG. When they were irradiated by several Gy 60Co γ-rays, Ce 1% doped GAGG crystal exhibited ∼20% light yield enhancement (positive hysteresis). This is the first time to observe positive hysteresis in Ce doped GAGG. On the other hand, other garnet materials did not show the positive hysteresis and their light yields were stable after 800 Gy irradiation except Pr:LuAG. The light yield of Pr:LuAG decreased largely. When irradiated Ce:GAGG which showed positive hysteresis was evaluated in Synchrotron facility (UVSOR), new excitation band was created around 60 nm.