| Project/Area Number |
17K19820
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Society medicine, Nursing, and related fields
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| Research Institution | Nagasaki University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
木村 真三 獨協医科大学, 医学部, 准教授 (50321849)
佐藤 斉 茨城県立医療大学, 保健医療学部, 教授 (90285057)
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| Project Period (FY) |
2017-06-30 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
Fiscal Year 2019: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2018: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Fiscal Year 2017: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | 大気圏内核実験 / 原子爆弾 / 蘚苔類 / フォールアウト / 放射能汚染 / 土壌コアサンプル / 放射線計測 / 最尤法 |
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| Outline of Final Research Achievements |
In substance, radioactive cesium contamination in moss around Japan was found originated from the Fukushima Daiichi Nuclear Power Plant accident with a few exceptions and the concentration depends on distance and direction from the plant. The concentration does not correlate with the neighboring soil.
Cs-137 concentration of the surface soil is highest at the sampling points located on the north and south of the Nagasaki atomic bombing hypocenter and the underground soil is highest on the east about Kyushu and Shikoku. The fact should be an influence of the atomic bombing or the nuclear tests. Scientific resources indicate higher Cs-137 concentration of soils on the east of the hypocenter too before the plant accident.
A method was developed to analyze the measurement data of the gamma-ray spectrometry more accurately. The method can visually indicate to what extent the analyzed results can explain the spectrum. Therefore, the method decreases the risk of incorrect analysis.
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| Academic Significance and Societal Importance of the Research Achievements |
蘚苔類は放射性降下物を濃縮し、局所的な大きなばらつきが生じないため、放射能の地理的分布を調べるのに好都合である。
原発事故による大量の放射能によって、原爆や核実験の影響の残された手がかりが消えつつあるが、地中の濃度を調べることにより、過去の放射能の地理的分布を垣間見ることができた。その分布は、既存の資料と一致したところから、この手法が有効であると判断できる。
スペクトル分析は、精度の問題だけでなく、誤検出、不明なピークなどの問題が生じやすい。今回開発した分析手法は、今のところ計算に時間と手間がかかるが、これらの問題の多くを解決できる。
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