Secular variation of cosmic rays in past ten million years using muon induced radionuclide in deep underground granite rocks
| Project/Area Number |
24540297
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Yamagata University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
HORIUCHI Kazuho 弘前大学, 理工学研究科, 助教 (00344614)
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| Co-Investigator(Renkei-kenkyūsha) |
MATSUZAKI Hiroyuki 東京大学, 総合研究博物館, 教授 (60313194)
DOSHITA Norihiro 山形大学, 理学部, 助教 (90451658)
NAKASHIMA Kazuo 山形大学, 理学部, 教授 (70159060)
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| Project Period (FY) |
2012-04-01 – 2015-03-31
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| Project Status |
Completed (Fiscal Year 2014)
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| Budget Amount *help |
¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Fiscal Year 2014: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2013: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2012: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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| Keywords | 宇宙線生成核種 / ミューオン / 加速器質量分析 / Be-10 / 花崗岩 / Al-26 / 高エネルギー / 宇宙線 / 永年変化 / AMS分析 |
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| Outline of Final Research Achievements |
The research objective is to detect the secular variations in high-energy cosmic rays, because the variations provide us an indication about movements of the earth in the galactic space for the last ten million years. High-energy cosmic muons produce long-lived radioactive nuclides in deep underground rock, such as Be-10 and Al-26, which have half-lives of 1.36×106 yr and 7.2×105 yr, respectively. Therefore, the concentrations of Be-10 and Al-26 in the rocks provide us with an indication of the long-term variations in high-energy cosmic rays over a few million years. We investigated the muon induced Be-10 and Al-26 in the extracted silica from high-energy muon exposed Toki-granite core samples, using Accelerator Mass Spectrometry. The behavior of production rates of muon induced nuclides was found out for the granite core.
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Report
(4 results)
Research Products
(10 results)
