2021 Fiscal Year Final Research Report
New picture of solar system and outer rim objects opened by nuclear gamma imaging observation
| Project/Area Number |
20K20428
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| Project/Area Number (Other) |
19H05500 (2019)
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| Research Category |
Grant-in-Aid for Challenging Research (Pioneering)
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| Allocation Type | Multi-year Fund (2020)
Single-year Grants (2019) |
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| Review Section |
Medium-sized Section 16:Astronomy and related fields
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| Research Institution | Kyoto University |
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Principal Investigator |
Tanimori Toru 京都大学, 理学研究科, 教授 (10179856)
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| Project Period (FY) |
2019-06-28 – 2022-03-31
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| Keywords | ガンマ線イメージング分光 / 元素合成 / 月面資源探査 / 電子飛跡検出型コンプトンカメラ / コンプトン散乱 / 機械学習 |
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| Outline of Final Research Achievements |
We have studied the possibility of the both observations of asteroid groups in the solar system and the chemical elements on the surfaces of rocky planets such as Moon by measuring spectroscopic images of γ-rays generated by collisions between cosmic rays and astronomical objects.
We developed the electron track detecting Compton camera (ETCC), which can determine the direction of nuclear gamma rays completely, and succeeded MeV gamma ray imaging spectroscopy for the first time in the world. Based on the observed galactic plane gamma rays in 2018 balloon observation, we improved PSF, which represents the gamma-ray collectivity, by using Deep Learning approach. Then the understanding of background gamma rays has been improved, and hence the experimental results could be reproduced independently from the cosmic-ray atmospheric gamma ray model and background gamma ray simulations, which verify the first direct detection of cosmic nuclear gamma rays exceeding over the background.
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| Free Research Field |
宇宙線物理学
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| Academic Significance and Societal Importance of the Research Achievements |
今まで核γ線の天体観測は50年以上前から注目されながら、ガンマ線方向測定が不可能だったため進展が非常に遅れていた。今回の成果は初めて完全な核γ線可視化を実現、これにより、2桁近く雑音低減に成功し宇宙からの核γ線の直接観測に成功、初めて銀河からのγ線画像を得ることで実証した。
これにより核γ線宇宙観測も他の天文学同様、幾何光学に基づく画像解析が可能となり、大きな発展が世界で初めて担保された。これより本申請の月面での元素の画像による資源探査も可能となる。さらに核ガンマ線を利用する全分野にイメージング分光技術の導入が可能となり、飛躍的進展が期待される。
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