Enhancing the direct search for dark matter in the XENON nT experiment with a water Cerenkov neutron detector

2023 Fiscal Year Final Research Report

• Project/Area Number: 19H00675
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 15:Particle-, nuclear-, astro-physics, and related fields
• Research Institution: The University of Tokyo
• 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)
• 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)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: neutron veto / dark matter / water Cherenkov / gadolinium sulfate

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.

Free Research Field

Dark Matter Direct Detection

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.