| Project/Area Number |
25610049
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Single-year Grants |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Chiba University |
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Principal Investigator |
KAWAI Hideyuki 千葉大学, 理学(系)研究科(研究院), 准教授 (60214590)
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| Project Period (FY) |
2013-04-01 – 2014-03-31
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| Project Status |
Completed (Fiscal Year 2013)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2013: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
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| Keywords | 粒子測定技術 / シリカエアロゲル / 難測定放射性物質 / リアルタイム測定 / チェレンコフカウンター / しきい値型 / ストロンチウム90 / リアルタイム計測 |
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| Research Abstract |
From Fukushima No.1 nuclear plant, a large amount of 90Sr is released into the Pacific Ocean. 90Sr emits high energy beta rays and attaches into born same as Ca. It is difficult to measure the density of 90Sr since it doesnot emit gamma rays. It is need 4 weeks in the standard measureing procedure.
We have Developped the real-time 90Sr counter. It is a threshold type Cherenkov counter with Silica Aerogel of n=1.05. It corresponds to the threshold kinetic energy of 1.2MeV for electrons. This counter has almost no efficiency for low energy beta rays and gamma rays. The lower limit of the detectable surface density is 0.1Bq/cm2 with 1 minute of measurement. It is easy to produce larger detector. The expected lower limit of the volume density for waters with 1cm thickness may be 10Bq/kg with 10 minutes of measurement.
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