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Search for the neutron electric dipole moment and the time reversal violation

Research Project

Project/Area Number 18H05230
Research Category

Grant-in-Aid for Scientific Research (S)

Allocation TypeSingle-year Grants
Review Section Broad Section B
Research InstitutionOsaka University

Principal Investigator

畑中 吉治  大阪大学, 核物理研究センター, 特任教授 (50144530)

Co-Investigator(Kenkyū-buntansha) 谷畑 勇夫  大阪大学, 核物理研究センター, 特任教授 (10089873)
三島 賢二  大学共同利用機関法人高エネルギー加速器研究機構, 物質構造科学研究所, 特別准教授 (20392136)
川崎 真介  大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 准教授 (20712235)
槇田 康博  大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 教授 (30199658)
渡邉 裕  大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 准教授 (50353363)
岡村 崇弘  大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 准教授 (90415042)
PIERRE EDGARD  大阪大学, 核物理研究センター, 特任助教(常勤) (30748893)
Project Period (FY) 2018-06-11 – 2023-03-31
Project Status Granted (Fiscal Year 2021)
Budget Amount *help
¥197,860,000 (Direct Cost: ¥152,200,000、Indirect Cost: ¥45,660,000)
Fiscal Year 2022: ¥11,570,000 (Direct Cost: ¥8,900,000、Indirect Cost: ¥2,670,000)
Fiscal Year 2021: ¥26,000,000 (Direct Cost: ¥20,000,000、Indirect Cost: ¥6,000,000)
Fiscal Year 2020: ¥39,130,000 (Direct Cost: ¥30,100,000、Indirect Cost: ¥9,030,000)
Fiscal Year 2019: ¥26,910,000 (Direct Cost: ¥20,700,000、Indirect Cost: ¥6,210,000)
Fiscal Year 2018: ¥94,250,000 (Direct Cost: ¥72,500,000、Indirect Cost: ¥21,750,000)
Keywords原子核(実験) / 素粒子(実験) / 超冷中性子 / 電気双極子モーメント / 基本対称性
Outline of Annual Research Achievements

UCN源各部(UCN生成部、液体重水素モデレータ、室温重水モデレータ、超流動ヘリウム容器、3He熱交換器)の配置と形状をモンテカルロシミュレーションにより最適化した。TRIUMFのビームパワーである500MeV×40μAの陽子ビームに対する超流動ヘリウムへの入熱は数値計算から10Wである。UCNを効率的に生成するためには陽子ビーム照射中も超流動ヘリウム温度を1 K程度に保たなければならない。超流動中のフォノン密度はその温度とともに上昇し、UCNがフォノンからエネルギーを得る逆反応によって失われてしまうからである。そのため、3Heを減圧することで低温を達成するヘリウム冷凍機を設計・製作した。冷却に用いる3Heガスは真空ポンプで排気後、循環して再利用される。室温から導入された3Heは大気圧の液体ヘリウム4槽で4.2Kに冷却され、次いで750Paに減圧され1.6Kに保たれた液体ヘリウムの満たされた1Kpot内で冷却される。1.6Kに冷却されて、3Heはジュールトムソンバルブを通じて断熱膨張することで1K以下に冷 却される。本設計では対向流型熱交換器を複数採用することで蒸発ヘリウム4の顕熱を十分に利用して3Heを予冷する。使用する熱交換器は数値計算より形状を最適化し、テスト器を製作し熱交換率測定を行った。テストでは、4Heガスを用い室温からの冷却を行い、冷却能力10Wに対応する3Heガス流量1.15g/s相当する流量に対し、十分な熱交換効率が得られることを確認した。この結果を用いてヘリウム3冷凍機を製作した。
TRIUMFでプロトタイプUCN源を運転し、UCN生成システムの検証とnEDM測定装置の要素開発を行った。500 MeV、1μAの陽子ビームを60秒間照射し70,000のUCN取り出し、UCN源内での寿命38秒を観測した。

Current Status of Research Progress
Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

ヘリウム3冷凍機が予定通り完成し、nEDM測定装置の要素開発が順調に進んでいる。

Strategy for Future Research Activity

プロトタイプのテスト結果を踏まえて、液体3Heと超流動ヘリウム間の熱交換器の実機を製作する。3Heガスが入手困難なため、1.2Kまでの冷却が可能な4Heを用いてテストを行う。熱交換器の性能を確認後、冷凍機を含む装置一式をTRIUMFに移送し、冷凍機の再組立てを行い真空、冷却等の健全性を確認する。TRIUMFで製作される液体重水素(LD2)モデレータとUCN生成部を接続し、UCN源を完成する。超流動ヘリウムをUCN生成部に貯蔵し、超流動ヘリウム中の温度測定を行い、超流動中の熱伝導を測定する。陽子ビームを用いたUCN生成実験を行い、輸送ガイド管等nEDM測定装置の要素開発を継続する。
500MeV、40μAでの連続運転を行えるよう、中性子生成標的を遠隔で脱着する機構を製作する。これは、放射化した標的の保守・交換の行う上で不可欠である。また、UCN生成中にnEDM装置のアクセスができるよう、必要なシールドを構築する。
アクティブ磁気シールド設計のために、nEDMセル領域の背景磁場の三次元マッピングを行う。並行して、小型磁場補償コイル系を製作し、磁場モニター、背景磁場の長時間安定性と短時間擾乱の制御をテストする。得られる結果をもとに、実機を製作する。数値シミュレーションに基づき、磁気シールドルームの構造設計を行い発注・製作を行う。磁気シールドルーム内に一様磁場生成コイル、シムコイルを設置し、nEDMセル領域の三次元磁場分布をマッピングする。得られた測定結果をもとにモンテカルロ計算を行い、偏極Cs磁力計の設置場所、フィードバックシステムを最適化する。
UCN源およびnEDM装置の安定稼働を確認し、陽子ビームパワー20 kWでの測定を開始する。

Assessment Rating
Interim Assessment Comments (Rating)

A: In light of the aim of introducing the research area into the research categories, the expected progress has been made in research.

Report

(6 results)
  • 2020 Abstract (Interim Assessment) ( PDF )   Interim Assessment (Comments) ( PDF )
  • 2019 Annual Research Report
  • 2018 Abstract ( PDF )   Comments on the Screening Results ( PDF )   Annual Research Report

Research Products

(42 results)

All 2020 2019 2018 Other

All Int'l Joint Research (2 results) Journal Article (5 results) (of which Int'l Joint Research: 5 results,  Peer Reviewed: 5 results,  Open Access: 5 results) Presentation (32 results) (of which Int'l Joint Research: 8 results,  Invited: 16 results) Remarks (2 results) Funded Workshop (1 results)

  • [Int'l Joint Research] TRIUMF/UBC/U. Winnipeg(カナダ)

    • Related Report
      2019 Annual Research Report
  • [Int'l Joint Research] TRIUMF/UBC/U. Winnipeg(カナダ)

    • Related Report
      2018 Annual Research Report
  • [Journal Article] Optimizing neutron moderators for a spallation-driven ultracold-neutron source at TRIUMF2020

    • Author(s)
      W. Schreyer, C.A. Davis, S. Kawasaki, T. Kikawa, C. Marshall, K. Mishima, T. Okamura, R. Picker
    • Journal Title

      Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

      Volume: 959 Pages: 163525-163525

    • DOI

      10.1016/j.nima.2020.163525

    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Fast-switching magnet serving a spallation-driven ultracold neutron source2019

    • Author(s)
      S. Ahmed, E. Altiere, K. Hatanaka, S. Kawasaki, Y.X. Watanabe et al.
    • Journal Title

      Phys. Rev. Accel. Beams

      Volume: 22 Pages: 102401-102401

    • DOI

      10.1103/physrevaccelbeams.22.102401

    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] A beamline for fundamental neutron physics at TRIUMF2019

    • Author(s)
      S. Ahmed, T. Andalib, K. Hatanaka, S. Kawasaki, *R. Pickar, Y.X. Watanabe et al.
    • Journal Title

      Nucl. Instr. Meth. A

      Volume: 927 Pages: 101-108

    • DOI

      10.1016/j.nima.2019.01.074

    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] First ultracold neutrons at TRIUMF2019

    • Author(s)
      S. Ahmed, E. Altiere, K. Hatanaka, S. Kawasaki, Y. Makida, K. Mishima, T. Okamura, *W. Schreyer, I. Tanihata, Y.X. Watanabe et al.
    • Journal Title

      Phys. Rev. C

      Volume: 99 Pages: 025503-025503

    • DOI

      10.1103/physrevc.99.025503

    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Cryogenic design for a high intensity ultracold neutron source at TRIUMF2019

    • Author(s)
      S. Kawasaki and T. Okamura for the TUCAN collaboration
    • Journal Title

      EPJ Web Conf.

      Volume: 219 Pages: 10001-10001

    • DOI

      10.1051/epjconf/201921910001

    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Presentation] TUCAN実験用ヘリウム3冷凍機の開発2020

    • Author(s)
      川崎真介
    • Organizer
      日本物理学会第75回年次大会
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] プロトタイプUCN源を用いた超流動ヘリウムの熱伝導率測定の試みについて2020

    • Author(s)
      松宮亮平
    • Organizer
      日本物理学会第75回年次大会
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] 中性子EDM測定のための加速器施設内の環境磁場補償システムの開発2020

    • Author(s)
      樋口嵩
    • Organizer
      日本物理学会第75回年次大会
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] 中性子EDM実験に使用する中性子輸送ガイド管の表面粗さ測定2020

    • Author(s)
      今城想平
    • Organizer
      日本物理学会第75回年次大会
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] The TRIUMF UltraCold Advanced Neutron source and Electric Dipole Moment experiment2019

    • Author(s)
      Wolfgang Schreyer
    • Organizer
      PSI2019
    • Related Report
      2019 Annual Research Report
    • Invited
  • [Presentation] Searching for the electric dipole moment of the neutron; a landscape overview2019

    • Author(s)
      Beatrice Franke
    • Organizer
      PSI2019
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Searches for the Neutron Electric Dipole Moment2019

    • Author(s)
      Thomas Lindner
    • Organizer
      J-PARC2019
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] TUCAN実験 中性子EDM測定のための磁場環境の開発2019

    • Author(s)
      樋口嵩
    • Organizer
      日本物理学会2019年秋季大会
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] TUCAN実験のための新しいUCN源の開発2019

    • Author(s)
      松宮亮平
    • Organizer
      日本物理学会2019年秋季大会
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] TUCAN EDM TRIUMF Ultra-cold Advanced Neutron project2019

    • Author(s)
      Jeffery Martin
    • Organizer
      FRIB-TA Topical Program
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Current Status of Neutron EDM experiments2019

    • Author(s)
      Jeffery Martin
    • Organizer
      INPC2019
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] nEDM searches worldwide2019

    • Author(s)
      Ruediger Picker
    • Organizer
      FPSTS19
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Progress on ultracold neutrons at TRIUMF2019

    • Author(s)
      Blair Jamieson
    • Organizer
      2019 CAP Congress
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] Improving the sensitivity of the neutron electric dipole experiment at TRIUMF2019

    • Author(s)
      Steve Sidhu
    • Organizer
      2019 CAP Congress
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] Producing ultracold neutrons with a spallation source and superfluid helium2019

    • Author(s)
      Wolfgang Schreyer
    • Organizer
      2019 CAP Congress
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] Measurements of the First Polarized Ultracold Neutrons at TRIUMF2019

    • Author(s)
      Sean Hansen-Romu
    • Organizer
      2019 CAP Congress
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] First high voltage breakdown in a test setup for the TUCAN neutron EDM experiment2019

    • Author(s)
      Florian Kuchler
    • Organizer
      2019 CAP Congress
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] Using PENTrack to study systematics in the neutron dipole moment measurement at TRIUMF2019

    • Author(s)
      Sean Vanbergen
    • Organizer
      2019 CAP Congress
    • Related Report
      2019 Annual Research Report 2018 Annual Research Report
  • [Presentation] The TRIUMF UltraCold Advanced Neutron source and Electric Dipole Moment experiment2019

    • Author(s)
      Wolfgang Schreyer,
    • Organizer
      PSI2019
    • Related Report
      2018 Annual Research Report
    • Invited
  • [Presentation] Current Status of Neutron EDM experiments,2019

    • Author(s)
      Jeffery Martin
    • Organizer
      INPC2019
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] UCN optics characterization for the next generation UCN source at TRIUMF2019

    • Author(s)
      E. Pierre
    • Organizer
      日本物理学会第74回年次大会
    • Related Report
      2018 Annual Research Report
  • [Presentation] Status of the TUCAN EDM experiment2018

    • Author(s)
      Ruediger Picker
    • Organizer
      Particle Physics with Neutrons at the ESS
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Cryogenic Design for TUCAN’s New UCN Source2018

    • Author(s)
      Shinsuke Kawasaki
    • Organizer
      Fifthe Meeting of the Nuclear Physics Divisions of the APS and JPS
    • Related Report
      2018 Annual Research Report
    • Invited
  • [Presentation] Symmetry Violation Search with Neutrons2018

    • Author(s)
      Beatrice Franke
    • Organizer
      Fifthe Meeting of the Nuclear Physics Divisions of the APS and JPS
    • Related Report
      2018 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Producing ultracold neutrons with a spallation source and superfluid helium,2018

    • Author(s)
      Ryohei Matsumiya
    • Organizer
      Fifthe Meeting of the Nuclear Physics Divisions of the APS and JPS
    • Related Report
      2018 Annual Research Report
    • Invited
  • [Presentation] Neutron Electric Dipole Moment Search by the TUCAN collaboration2018

    • Author(s)
      Edgard Pierre
    • Organizer
      Fifthe Meeting of the Nuclear Physics Divisions of the APS and JPS
    • Related Report
      2018 Annual Research Report
    • Invited
  • [Presentation] Towards the nEDM search at TRIUMF2018

    • Author(s)
      Ryohei Matsumiya
    • Organizer
      Hadron 2018 workshop
    • Related Report
      2018 Annual Research Report
    • Invited
  • [Presentation] Quantum Vortex Limitations to Ultracold Neutron Production2018

    • Author(s)
      Jeffery Martin
    • Organizer
      2018 CAP Congress
    • Related Report
      2018 Annual Research Report
  • [Presentation] The ultra-cold neutron facility at TRIUMF2018

    • Author(s)
      Florian Kuchler,
    • Organizer
      2018 CAP Congress
    • Related Report
      2018 Annual Research Report
  • [Presentation] Neutron electric dipole moment measurement: systematics and magnetic field control2018

    • Author(s)
      Beatrice Franke
    • Organizer
      2018 CAP Congress
    • Related Report
      2018 Annual Research Report
  • [Presentation] Development of a High Intensity Ultracold Neutron Source at TRIUM2018

    • Author(s)
      Shinsuke Kawasaki
    • Organizer
      International Workshop on Particle Physics at Neutron Source 2018
    • Related Report
      2018 Annual Research Report
    • Invited
  • [Presentation] Neutron scattering cross section of Diamond Nano Particle2018

    • Author(s)
      Kenji Mishima
    • Organizer
      International Workshop on Particle Physics at Neutron Source 2018
    • Related Report
      2018 Annual Research Report
    • Invited
  • [Remarks]

    • URL

      http://fnp.kek.jp

    • Related Report
      2019 Annual Research Report
  • [Remarks]

    • URL

      http://fnp.kek.jp

    • Related Report
      2018 Annual Research Report
  • [Funded Workshop] RCNP Workshop on Fundamental physics using neutrons and atoms2018

    • Related Report
      2018 Annual Research Report

URL: 

Published: 2018-06-12   Modified: 2022-05-19  

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