Production and determination of Th-229m, a key material for the next generation atomic-nuclear clock
| Project/Area Number |
15K13396
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
General applied physics
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Co-Investigator(Renkei-kenkyūsha) |
NANBU kenichi 東北大学, 電子光理学研究センター, 技術専門職員 (00422072)
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| Project Period (FY) |
2015-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2016: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2015: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | 核異性体 / 原子核励起 / トリウム / 放射化学 / 核化学 / 核励起 / 原子核 / 標準 |
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| Outline of Final Research Achievements |
Thorium nucleus with a mass number of 229 (Th-229g) have a metastable state (Th-229m) with the lowest excitation energy known to date. This excitation energy is to be 7-8 eV, vacuum ultraviolet light. The transition between Th-229m and Th-229g has a potential for a high-precision "atomic nuclear" clock. However, there are no reports on direct excitation from Th-229g to Th-229m. In this study, we developed a high current electron irradiation apparatus for direct excitation of Th-229g and evaluated its performance. In addition, we also investigated a target preparation to withstand high current electron beam and prepared Th-229g material from U-233.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究には，これまで1994年に数 eVの励起エネルギーを持つ特異な原子核であることが知られて以来，誰も成功していないTh-229mの直接崩壊信号の観測を目指すという基礎科学的な意義がある。また，本研究で行われたTh-229電子線励起の試みはTh-229gのレーザー励起法の開発など次のステップに進む上での基礎データとなるため，次世代”原子核”時計を開発する上での重要な一歩となる。また，本研究の過程でU-233から分離され研究に使えるように整備されたTh-229試料は，娘核種に核医学分野で注目されるAc-225など有用RIを含むため，本研究以外にも利用されつつある。
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Report
(5 results)
Research Products
(3 results)
