Study of Filled Liquid for Efficient Background Reduction in Large Volume Liquid Xenon Detector

• Project/Area Number: 16K05370
• 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: Nihon University (2018); The University of Tokyo (2016-2017)
• Principal Investigator: OGAWA Hiroshi 日本大学, 理工学部, 助手 (20374910)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000); Fiscal Year 2018: ¥260,000 (Direct Cost: ¥200,000、Indirect Cost: ¥60,000); Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2016: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
• Keywords: 暗黒物質探索 / 光検出器 / 低温物性 / 極低放射能技術 / 素粒子・原子核物理実験 / 素粒子実験 / 暗黒物質 / 極低バックグラウンド

Outline of Final Research Achievements

I would like to prepare a method to improve sensitivity in the next or subsequent dark matter search experiment. One approach is to fill the vicinity of the detector surface with a liquid fill liquid and separate it from the liquid xenon area which the event from the dark mater responds to. This is expected to prevent background events from the detector surface from being mistaken as fiducial volume events and to improve the sensitivity of the dark resource search. This filling liquid is required to transmit vacuum ultraviolet light, to be liquid at liquid xenon temperature (－100 deg), to be resistant to physical properties, and to have low background. This study will carry out the selection of this filling liquid and the evaluation of its performance.

Academic Significance and Societal Importance of the Research Achievements

液体キセノンは低バックグラウンド実験において、シンチレータ―として、暗黒物質探索だけでなく、太陽ニュートリノ観測、0νββ探索にも大変有望なものであり、将来における大型化が必要不可欠である。よって、本研究は、“想定外”のバックグラウンド事象をコントロールしつつ、大型化のために有用な研究である。

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] 液体キセノンを用いた暗黒物質探索の結果と、探索感度向上の研究 (2018)
  • Author(s): 小川 洋
  • Organizer: 日本大学学部連携ポスターセッション
• [Presentation] Search for WIMPs with background evaluation in a fiducial volume by XMASS-I. (2017)
  • Author(s): Hiroshi Ogawa for XMASS collaboration
  • Organizer: 35th International Cosmic Ray Conference (ICRC2017) July 12-20, 2017 BEXCO, BUSAN, KOREA
  • Int'l Joint Research / Invited
• [Presentation] XMASS実験：有効体積解析による暗黒物質探索の為のバックグラウンドの評価 (2017)
  • Author(s): 小川 洋 他XMASS collaboration
  • Organizer: 日本物理学会２０１７年秋季大会 宇都宮大学峰キャンパス