Development of innovative electrostatic septum using carbon nanotube wires

• Project/Area Number: 17K05132
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Quantum beam science
• Research Institution: High Energy Accelerator Research Organization
• Principal Investigator: Tomizawa Masahito 大学共同利用機関法人高エネルギー加速器研究機構, 加速器研究施設, 教授 (80197920)
• Co-Investigator(Kenkyū-buntansha): 武藤 亮太郎 大学共同利用機関法人高エネルギー加速器研究機構, 加速器研究施設, 准教授 (50392147) ; 岡村 勝也 大学共同利用機関法人高エネルギー加速器研究機構, その他部局等, シニアフェロー (50415048) ; 新垣 良次 大学共同利用機関法人高エネルギー加速器研究機構, 加速器研究施設, 技師 (70625251)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000); Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2018: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000); Fiscal Year 2017: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
• Keywords: 遅い取り出し / カーボンナノチューブ / ビームロス / 静電セプタム / 高電圧特性 / 真空特性 / ワイヤー / 加速器

Outline of Final Research Achievements

A stable 50 kW slow-extracted beam has been being delivered to the experimental hall (hadron hall) to execute various experiments on nuclear physics and elementary particle physics in J-PARC. However future experimental programs need beam powers much more than 100 kW. The slow extraction technique makes an inevitable beam loss around the electrostatic septum (ESS) using a septum to make an electric field distribution with a step function. The beam loss generated by hitting at the septum is most critical and limits the beam power. Tungsten including rhenium (W/Re) is used for the septum material for the present ESSs. If the material with a low atomic number can be used for the septum, the beam loss can be drastically reduced. We have developed carbon nanotube (CNT) wires for the ESS. Voltage supply test has been carried out using a test stand fabricated to investigate various basic characteristics of the CNT wire.

Academic Significance and Societal Importance of the Research Achievements

本研究で行うカーボン・ナノチューブをセプタムとする新しいアイディアを導入した静電セプタム開発研究は、世界で始めて挑戦する非常に独創的なものである。本研究の目的に適合したカ ーボン・ナノチューブワイヤーの試作に世界で初めて成功し、高真空中で高電圧試験を実施できたことは、本研究の独創性と成果を 裏付けるものとなっている。本研究の成果による今後の実用化の取り組みにより、遅い取り出しビーム性能を大幅に向上させることが可能となり、大強度の遅い取り出しビームを利用する原子核・素粒子実験に与えるインパ クトは非常に大きい。

Research Products

• [Journal Article] Slow extraction from the J-PARC main ring using a dynamic bump (2018)
  • Author(s): Tomizawa M.、Arakaki Y.、Kimura T.、Muto R.、Murasugi S.、Okamura K.、Sato H.、Shirakabe Y.、Yanaoka E.
  • Journal Title: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Volume: 902 Pages: 51-61
  • DOI: 10.1016/j.nima.2018.06.004
  • Peer Reviewed
• [Journal Article] Beam Optics Design of Stretcher Ring and Transfer Line for J-PARC Slow Extraction (2018)
  • Author(s): Tomizawa Masahito、Konaka Akira、Muto Ryotaro、Ogitsu Toru
  • Journal Title: Journal of Physics: Conference Series Volume: 1067 Pages: 042004-042004
  • DOI: 10.1088/1742-6596/1067/4/042004
  • Peer Reviewed
• [Presentation] Initial Tests for Electrostatic Septum Using Carbon Nanotube Wires (2019)
  • Author(s): Masahito Tomizawa
  • Organizer: 2019 J-PARC Symposium
  • Int'l Joint Research
• [Presentation] ミューオン電子転換過程探索実験のための 8 GeV 遅い取り出しビーム試験 (2018)
  • Author(s): 冨澤正人
  • Organizer: 加速器学会
• [Presentation] Status and Beam Power Ramp-Up Plans of the Slow Extraction Operation at J-Parc Main Ring (2018)
  • Author(s): M. Tomizawa
  • Organizer: The 61st ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams
  • Int'l Joint Research / Invited
• [Presentation] J-PARC Slow Extraction Overview (2017)
  • Author(s): M. Tomizawa
  • Organizer: Slow Extraction workshop
  • Int'l Joint Research / Invited