Crystal Growth and Luminescence Properties of Yb-doped Gd3Al2Ga3O12 Infra-red Scintillator

• Yb-doped Gd3Al2Ga3O12 (Yb:GAGG) crystal was grown by a micro-pulling down method.
• Crystal structure and average chemical composition of Yb:GAGG was examined.
• Yb:GAGG crystal was highly transparent in infra-red region from 650 to 1200 nm.
• Yb:GAGG showed infra-red scintillation peaks at 1030 nm under X-ray excitation.

1-mol%-Yb-doped Gd3Al2Ga3O12 infra-red scintillator crystal has been studied as a novel implantable radiation monitor in radiation therapy. Powder X-ray diffraction measurement and chemical analysis with a field emission scanning microscope and wavelength dispersive spectrometer determined its garnet structure and average chemical composition of Yb0.03±0.01Gd2.99±0.07Al2.21±0.08Ga2.64±0.09O12.10±0.09. Transmittance measurements reached high values of approximately 70% in the human body transparency region between 650 to 1200 nm. Photoluminescence peaks were detected around 970 and 1030 nm under the 940 nm excitation with a Xe lamp. Infra-red scintillation emissions were clearly observed around 970 and 1030 nm due to Yb3+ 4f–4f transitions under X-ray excitation. Therefore, these results suggest that Yb-doped Gd3Al2Ga3O12 might be used as an infra-red scintillator material.