| Project/Area Number |
04808035
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Nuclear engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
YAMADERA Akira Tohoku Univ., CYRIC, Research Associate, サイクロトロン・ラジオアイソトープセンター, 助手 (90004465)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Takasi Tohoku Univ., CYRIC, Professor, サイクロトロン・ラジオアイソトープセンター, 教授 (70026029)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1993: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1992: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Personal dosimeter / Monomer detector / Imaging plate / Fast neutron / 速中性子検出器 / 中性子検出器 / 個人線量計 / ポリマー |
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| Research Abstract |
We developed a new type fast neutron dosimeter by using polymerization reaction of methyl methacrylate.
Polymer particles were formed by the recoil atoms which had been scattered with fast neutrons. The number of the particles was counted by the counter which we have debeloped. Solution which contained polymer particles were irradiated with Helium-Neon laser(632.8nm) and scattered photon from polymer particle was measured with photomultiplier tube which is set at 90ﾟC for laser beam. After irradiation, detector solution was heated to 50ﾟC in a water bath, mixed with de-aired methanol and measured. The sensitivity for ^<252>Cf neutrons was 236(〕SY.+-.〔)85 pulse/(sec.mSV) for 4ml detector solution. It was not so high sensitivity that we had expected. One of the reasons is that SN ratio is very small, the noises are the lights scattered at the surface of the flow through cell and fine particle contaminants in the detector solution.
We found that this detector was sensitive to gamma-rays too. For subtracting gamma-ray components, we developed high sensitive passive type dosimeter for gamma-rays. Imaging plates was irradiated with x-rays or gamma-rays, and the linearity between 1 cm dose equivalint and PSL density was observed for very wide range of 1 muSv to 10 mSv and limit of detection was 0.06 muSv for 8 hour natural background activity. It was found out that the imaging plate detector was useful as subtracting gamma-ray components when the polymer detector was exposed in gamma-ray and neutron mixed field.
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