| Project/Area Number |
19H00675
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Medium-sized Section 15:Particle-, nuclear-, astro-physics, and related fields
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Martens Kai 東京大学, カブリ数物連携宇宙研究機構, 准教授 (20535025)
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| Co-Investigator(Kenkyū-buntansha) |
竹田 敦 東京大学, 宇宙線研究所, 准教授 (40401286)
伊藤 好孝 名古屋大学, 宇宙地球環境研究所, 教授 (50272521)
身内 賢太朗 神戸大学, 理学研究科, 准教授 (80362440)
平出 克樹 東京大学, 宇宙線研究所, 特任助教 (10584261)
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| Project Period (FY) |
2019-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥40,690,000 (Direct Cost: ¥31,300,000、Indirect Cost: ¥9,390,000)
Fiscal Year 2022: ¥9,360,000 (Direct Cost: ¥7,200,000、Indirect Cost: ¥2,160,000)
Fiscal Year 2021: ¥9,230,000 (Direct Cost: ¥7,100,000、Indirect Cost: ¥2,130,000)
Fiscal Year 2020: ¥8,580,000 (Direct Cost: ¥6,600,000、Indirect Cost: ¥1,980,000)
Fiscal Year 2019: ¥13,520,000 (Direct Cost: ¥10,400,000、Indirect Cost: ¥3,120,000)
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| Keywords | neutron veto / dark matter / water Cherenkov / gadolinium sulfate / direct detection / gadolinium / neutron tagging / WIMP / solar axion / 暗黒物質 / 水チェレンコフ型検出器 / 中性子検出器 |
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| Outline of Research at the Start |
暗黒物質(DM)の正体の解明は現代の物理学における最重要課題の一つである。有効質量約4tの液体キセノン検出器を用いたXENONnT実験は世界最高感度でのDM探索を行う。この実験ではDMによるキセノン原子核の反跳現象を探索するが、検出器内部の放射性不純物起因の中性子でも同様の現象が起こるため、中性子を同定する中性子検出器がDMの証拠を掴む鍵を握る。本研究ではスーパーカミオカンデで培われた中性子検出技術の初の転用例として、中性子検出器の建設や較正作業、安定な運転を行い、中性子による事象の80％以上を排除する。これで感度を一桁向上し、DM－核子散乱断面積2x10-48cm2の探索感度で発見を目指す。
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| Outline of Final Research Achievements |
Neutrons can mimic dark matter particle detection, which is why dark matter detectors like XENONnT need a neutron veto (NV). Under this grant we developed and implemented a new NV technology based on the EGADS gadolinium water Cherenkov technology originally developed at Kamioka for Super-Kamiokande.
We successfully installed and commissioned this new NV at the XENONnT dark matter experiment, where it informed the only blind dark matter analysis published so far by the current generation of liquid xenon dark matter experiments: It is producing science output already at this early stage.
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| Academic Significance and Societal Importance of the Research Achievements |
While our new technology greatly reduces the environmental risk from a neutron veto leak alone, the scientific reach of the whole detector is the same. And finding dark matter particles will surely change our understanding of the universe and the role matter plays in it.
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