Development of new techniques for next generation of dark matter search detectors

• Project/Area Number: 17K05465
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: The University of Tokyo
• Principal Investigator: Kobayashi Kazuyoshi 東京大学, 宇宙線研究所, 特任助教 (70466861)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2017: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: 暗黒物質探索 / キセノン / 暗黒物質 / 表面バックグラウンド / ラドン

Outline of Final Research Achievements

Mechanism of 210Pb accumulation on surface of material was understood better and The prospect of an end to the survey was seen for no accumulation using area neutralization system. Also, the prospect of an end to the survey was seen for sensitivity improvement of radon concentration using the electrostatic collection type radon detector.

Academic Significance and Societal Importance of the Research Achievements

暗黒物質は宇宙の質量の約４分の３を占めるがその正体はなぞのままである。この暗黒物質を探索実験では検出器部材に含まれる、または付着した放射性不純物が暗黒物質の信号を疑似的に作るため、放射性不純物の除去、付着させないことが実験を成功させるカギとなる。本研究により表面に放射性不純物を付着させない方法確立への見通しがたった。また、放射性不純物のなかでも重要なラドンの濃度測定の感度向上のめどがたった。

Research Products

• [Journal Article] A direct dark matter search in XMASS-I (2019)
  • Author(s): K. Abe et al.
  • Journal Title: Physics Letters B Volume: B789 Pages: 45-53
  • DOI: 10.1016/j.physletb.2018.10.070
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Surface and bulk Pb210/Po210 contamination study on copper and PTFE using low background alpha counter (2019)
  • Author(s): Kazuyoshi Kobayashi
  • Organizer: Low Radioactivity Techniques 2019
  • Int'l Joint Research
• [Presentation] Latest results from XMASS (2019)
  • Author(s): Kazuyoshi Kobayashi
  • Organizer: 5th international conference on the Dark Side of the Universe
  • Int'l Joint Research / Invited
• [Presentation] Dark matter searches in XMASS (2018)
  • Author(s): 小林兼好
  • Organizer: XXXIX International Conference on High Energy Physics
  • Int'l Joint Research
• [Presentation] 液体キセノンを用いた暗黒物質探索 (2018)
  • Author(s): 小林兼好
  • Organizer: 平成３０年度東京大学宇宙線研究所共同利用研究成果発表会
• [Presentation] Recent results with XMASS (2017)
  • Author(s): 小林兼好
  • Organizer: Exploring the Dark Universe
  • Int'l Joint Research / Invited
• [Presentation] 検出器表面バックグラウンド (2017)
  • Author(s): 小林兼好
  • Organizer: 新学術宇宙の歴史をひもとく地下素粒子原子核研究：第９回Ｂ０２班若手研究会
• [Remarks] XMASS
  • URL: http://www-sk.icrr.u-tokyo.ac.jp/xmass/index.html