Development of plasma radiation imaging diagnostic in neutron environment

• Project/Area Number: 17K14900
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Nuclear fusion studies
• Research Institution: National Institute for Fusion Science
• Principal Investigator: Mukai Kiyofumi 核融合科学研究所, ヘリカル研究部, 助教 (90632266)
• Project Period (FY): 2017-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2017: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
• Keywords: ボロメータ / 輻射計測 / イメージング / 真空蒸着 / 中性子 / プラズマ計測 / 核融合 / プラズマ・核融合

Outline of Final Research Achievements

In order to reduce the local heat load in a fusion reactor, an operation scenario to disperse the heat load by enhancing the plasma radiation loss is investigated. An infrared imaging video bolometer (IRVB) is developed to reveal the mechanism underlying the scenario and the IRVB is required in order to survive the neutron environment of a fusion reactor.
In this study, a new method for coating carbon on both sides of a IRVB foil detector with high-reproducibility and high-uniformity was developed, which is important to calibrate the detector in the neutron environment. By using the evaporation technique instead of the conventional spray technique, the calibration error under the neutron environment could be suppressed to less than approximately 10%. Moreover, it is confirmed that the characteristics of the new detector experienced no degradation for the total neutron emission of 3.6 * 10^18.

Academic Significance and Societal Importance of the Research Achievements

核融合発電の実現には装置内壁の局所熱負荷を減らす必要があり、輻射（放射）損失を増やして熱負荷を分散する、放射ダイバータと呼ばれる運転方法が検討されている。その物理機構の解明に必要な計測器としてイメージングボロメータの開発が進められており、核融合炉で想定される中性子環境へ適用させることが課題であった。
本研究において、中性子環境下で較正可能なイメージングボロメータの検出器を開発したことで、今後の大型装置での放射ダイバータ研究にイメージングボロメータが活用され、その物理機構の解明が進展することが期待される。

Research Products

• [Journal Article] Neutron Shielding Design of Infrared Imaging Video Bolometer for LHD Deuterium Experiment (2019)
  • Author(s): Mukai Kiyofumi、Nishitani Takeo、Ogawa Kunihiro、Peterson Byron J.
  • Journal Title: IEEE Transactions on Plasma Science Volume: 47 Issue: 1 Pages: 18-21
  • DOI: 10.1109/tps.2018.2879604
  • NAID: 120007166310
  • Peer Reviewed
• [Journal Article] Improvement of infrared imaging video bolometer for application to deuterium experiment on the large helical device (2018)
  • Author(s): Mukai K.、Abe R.、Peterson B. J.、Takayama S.
  • Journal Title: Review of Scientific Instruments Volume: 89 Issue: 10
  • DOI: 10.1063/1.5038947
  • NAID: 120007166308
  • Peer Reviewed
• [Presentation] Improvement of Infrared Imaging Video Bolometer for Application to LHD Deuterium Experiment (2018)
  • Author(s): K. Mukai, R. Abe, B. J. Peterson, S. Takayama
  • Organizer: 22nd Topical Conference on High-Temperature Plasma Diagnostics
  • Int'l Joint Research
• [Presentation] Multi-Dimensional Measurement of Plasma Radiation on LHD (2018)
  • Author(s): K. Mukai, B. J. Peterson, N. Tamura
  • Organizer: The 27th International Toki Conference on Plasma and Fusion Research & The 13th Asia Pacific Plasma Theory Conference
  • Int'l Joint Research
• [Presentation] LHDにおける輻射分布の多次元計測 (2018)
  • Author(s): 向井清史、B. J. Peterson、田村直樹
  • Organizer: 第35回プラズマ・核融合学会年会
• [Presentation] LHD重水素実験における イメージングボロメータ計測 (2017)
  • Author(s): 向井清史、阿部亮太、B. J. Peterson、高山定次
  • Organizer: Plasma Conference 2017