TY - JOUR
T1 - Development of a single crystal with a high index of refraction
AU - Kurosawa, Shunsuke
AU - Kochurikhin, Vladimir V.
AU - Yamaji, Akihiro
AU - Yokota, Yuui
AU - Kubo, Hidetoshi
AU - Tanimori, Toru
AU - Yoshikawa, Akira
N1 - Funding Information:
This work is partially supported by (i) Japan Society for the Promotion of Science Research Fellowships for Young Scientists (S. Kurosawa), (ii) the funding program for next generation world-leading researchers, Japan Society for promotion of science, (iii) SENTAN of Japan Science, Strategic advanced technology support program, METI (the Ministry of Economy, Trade and Industry), and (iv) the Association for the Progress of New Chemical Technology. In addition, we would like to thank the following persons for their support: Mr. Y. Nakamura, Mr. H. Uemura, Ms. K. Toguchi, and Ms. M. Sasaki of the Tohoku University.
PY - 2013
Y1 - 2013
N2 - 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 Lu3Ga 5O12 (LuGG) crystals grown by a micro-pulling-down (μ-PD) method. The GGG, YGG and LuGG crystals were found to have refractive indices of ~2.5, ~2.3 and ~2.3 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 10±1ns and 10±2ns, respectively, using a photomultiplier tube (Hamamatsu R6231-100). Cherenkov light of the GGG crystal could be observed for the gamma-ray irradiation.
AB - 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 Lu3Ga 5O12 (LuGG) crystals grown by a micro-pulling-down (μ-PD) method. The GGG, YGG and LuGG crystals were found to have refractive indices of ~2.5, ~2.3 and ~2.3 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 10±1ns and 10±2ns, respectively, using a photomultiplier tube (Hamamatsu R6231-100). Cherenkov light of the GGG crystal could be observed for the gamma-ray irradiation.
KW - Cherenkov radiator
KW - Garnet crystal
KW - GdGa O
KW - GGG
KW - TOF PET
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U2 - 10.1016/j.nima.2013.08.018
DO - 10.1016/j.nima.2013.08.018
M3 - Article
AN - SCOPUS:84889097066
SN - 0168-9002
VL - 732
SP - 599
EP - 602
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
ER -