Development of a single crystal with a high index of refraction

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• 作者：Shunsuke Kurosawa ; Vladimir V. Kochurikhin ; Akihiro Yamaji ; Yuui Yokota ; Hidetoshi Kubo ; Toru Tanimori ; Akira Yoshikawa
• 关键词：Cherenkov radiator ; TOF PET ; Garnet crystal ; GGG ; Gd3Ga5O12
• 刊名：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
• 出版年：21 December, 2013
• 年：2013
• 卷：732
• 期：Complete
• 页码：599-602
• 全文大小：674 K

文摘

Time-of-flight Positron emission tomography (TOF-PET) is one of the next-generation medical imaging methods, which requires scintillators with a very short decay time. However, the shortest scintillation decay times are typically 20-30 ns, and these values are not sufficient for TOF-PET. Cherenkov counters are used in high energy physics and they are expected to be applied in medical imaging due to their short decay time. Here, high-refractive index materials are necessary for Cherenkov radiators to reach a high light output. We measured refractive indices of Gd₃Ga₅O₁₂ (GGG), Y₃Ga₅O₁₂ (YGG) and Lu₃Ga₅O₁₂ (LuGG) crystals grown by a micro-pulling-down method. The GGG, YGG and LuGG crystals were found to have refractive indices of , and at 400 nm, respectively. Then we grew a 40 mm diameter GGG crystal by the Czochralski method, and the emission decay times of the GGG crystals irradiated with muons and gamma rays were and , respectively, using a photomultiplier tube (Hamamatsu R6231-100). Cherenkov light of the GGG crystal could be observed for the gamma-ray irradiation.