| Project/Area Number |
12640247
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | Tohoku University |
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Principal Investigator |
INOUE Kunio Tohoku University, Faculty of Science, Associate Professor, 大学院・理学研究科, 助教授 (10242166)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | Solar Neutrino / Gadolinium / Liquid Scintillator / 液体シンチレータ |
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| Research Abstract |
Research and development for a realtime measurement of low energy solar neutrinos with charged current interaction has been performed. The ^<160>Gd atom is quite suitable for this purpose because of its very low energy reaction threshold enabling pp neutrino detection and of very characteristic three fold coincidence signal useful for background rejection. In this research, it was focused on solving Gadolinium into fast liquid scintillator so that indispensable three fold coincidence can be achieved. Performance measurement of the Gadolinium loaded liquid scintillator and feasibility test as low energy solar neutrino detector are also carried out. Performing wide survey of solvents and Gadolinium compounds, an excellent combination of PsuedoCumene (60 %), detergent NS210 (40 %) and Gd(NO_3)_36H_2O was found that it can hold Gadolinium up to 8 weight %. The performance of the Gadolinium loaded liquid scintillator at 5wt % was measured to be ; 2ns as decay time, 3500photons/MeV, effective light transmission 39 cm, alpha quench 7.4 at 7.8MeV and alpha dicrimination 95 % resulting applicable to the low energy solar neutrino observation. A simulation of 1m^3 size detector provided efficiencies of three fold coincidence identification to be 65 % for ^7Beneutrino signal and 63 % for pp neutrino even with a selection criteria that has less than 0.05 % misidentification probability to the problematic ^<152>Gd alpha decay. This scintillator costs only one tenth in relative to the other competing developments. Thus, the very competitive Gadolinium loaded liquid scintillator has been successfully developed.
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