| Project/Area Number |
12640283
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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 | Saga University |
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Principal Investigator |
OHSUMI Hideaki Saga University, Associated Professor, 文化教育学部, 助教授 (70176882)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2002: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Double beta decays / Underground Laboratory / Neutrino / バックグランド |
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| Research Abstract |
(1) The NEMO 3 collaboration is looking for neutrinoless double beta decays to investigate Majorana neutrino mass in the sub-eV region. Construction of the NEMO 3 detector has been completed, and the detector is now operating normally in the Frejus underground laboratory (Laboratoire de Souterrain de Modane, LSM). In this research, we studied the fluxes of γ-rays and neutrons in the underground laboratory, which are the backgrounds of the double beta decay study.
(2) We reported the y-ray flux measurement in the LSM using a large volume sodium iodide (NaI) scitillator. Since NaI is sensitive to both γ-rays and neutrons we used different shielding configurations to extract the pure γ-ray flux. Since the expected counting rate is very low, the present experiment has been carried out for more than 3 years.
(3) Radon is known to be one of the most serious origins of background of our, experiment. High sensitive radon detectors are developed for the radon concentration measurement of the chamber gas etc. used for the NEMO 3 detector.
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