Primordial lithium 7 problem studied by using stopped unstable nucleus target
| Project/Area Number |
16H03980
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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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 | Osaka University |
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Principal Investigator |
Tamii Atsushi 大阪大学, 核物理研究センター, 准教授 (20302804)
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| Co-Investigator(Kenkyū-buntansha) |
牧井 宏之 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 先端基礎研究センター, 研究職 (20425573)
山口 英斉 東京大学, 大学院理学系研究科(理学部), 講師 (30376529)
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| Research Collaborator |
Kobayashi Nobuyuki
Inoue Azusa
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥18,330,000 (Direct Cost: ¥14,100,000、Indirect Cost: ¥4,230,000)
Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2017: ¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Fiscal Year 2016: ¥11,960,000 (Direct Cost: ¥9,200,000、Indirect Cost: ¥2,760,000)
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| Keywords | 宇宙リチウム問題 / ビッグバン元素合成 / 不安定核停止標的 / インプラント / 共鳴反応 / リチウム7問題 / (d,p)反応 |
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| Outline of Final Research Achievements |
The resonant reaction between a beryllium-7 and a deuteron has been measured in the energy range of 100-400 keV. The experiment aims at solving the cosmological lithium problem, that is the overestimation of the lithium abundance after Big Bang than the astronomical observation. We applied a newly developed technique of stopped unstable nucleus target. We achieved a beryllium-7 density of 6.1 times 10 to 11 per square mm by implantation at CNS, Univ. of Tokyo and 6.3 times 10 to 12 by activation at Tandem accelerator, Kobe Univ. By using the targets, we successfully measured the cross section of the reaction.
The data will give the conclusion on the contribution of the reaction to the cosmological lithium problem, though the data analysis is still in progress. The successful proof-of-principle experiment was a big step for the future extensions of the experiments using the stopped unstable nucleus target.
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| Academic Significance and Societal Importance of the Research Achievements |
測定に成功したベリリウム7と重陽子との共鳴反応率は、宇宙リチウム問題において重要な反応である。現在宇宙リチウム問題の解決にむけて、宇宙論や標準理論の修正の議論、新粒子の提唱などが行われている状況であり、核物理の情報のみでどこまでこの問題を追い込めるかを見極めることは極めて大きい意義を持つ。
また、我々が開発を進めてきた不安定核停止標的という新しい技術を適用することで従来にない精度での核反応測定に成功したことは、今後の不安定核を対象とする核物理の進展に新たな潮流をもたらすものであり、同手法を用いた実験研究の飛躍的な発展をもたらす。
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Report
(4 results)
Research Products
(27 results)
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[Journal Article] Test of the Brink-Axel Hypothesis for the Pygmy Dipole Resonance2017
Author(s)
Martin D.、von Neumann-Cosel P.、Tamii A.、Aoi N.、Bassauer S.、Bertulani C.?A.、Carter J.、Donaldson L.、Fujita H.、Fujita Y.、Hashimoto T.、Hatanaka K.、Ito T.、Krugmann A.、Liu B.、Maeda Y.、Miki K.、Neveling R.、Pietralla N.、Poltoratska I.、Ponomarev V.?Yu.、Richter A.、Shima T.、Yamamoto T.、Zweidinger M.
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Journal Title
Physical Review Letters
Volume: 119
Issue: 18
Pages: 1-5
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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[Presentation] E1・M1応答と和則2016
Author(s)
Atsushi Tamii
Organizer
日本物理学会秋の分科会
Place of Presentation
宮崎大学
Year and Date
2016-09-21
Related Report
Invited
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