Study on Quench Detection and Protection Technologies of No-Insulation HTS Magnet for Next-Generation MRI and NMR

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K18068
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Power engineering/Power conversion/Electric machinery
• Research Institution: Waseda University
• Principal Investigator: Wang Tao 早稲田大学, 理工学術院総合研究所(理工学研究所), その他(招聘研究員) (60707818)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 無絶縁コイルシステム / クエンチ検出 / コイル保護 / 高温超伝導

Outline of Final Research Achievements

We developed a program for analyzing the basic behaviors of no-insulation coil-system applied in MRI and NMR. Using this analysis program, the behavior of local normal-state transition and the current characteristic in the coil-system were clarified. According to the clarification of the behavior of the current distribution inside the sub-coil in the coil-system during charging, the discussion on the factors influencing the current distribution was conducted. Moreover, in order to meet the application requirement of the magnet in meter-class bore MRI, the numerical investigation on the ratio between self-inductance and turn-to-turn contact resistivity was conducted, which is an important condition influenced the charging process. Finally, the necessary cooling load of sub-coil was discussed based on evaluating the Joule-heat generation of the NI magnet.

Free Research Field

超電導応用工学

Academic Significance and Societal Importance of the Research Achievements

有限要素法及び分布常数回路網解析に基いてメーター級大口径MRI用無絶縁コイルシステムの基礎特性を解析可能なコードを開発した。この解析コードを用いて，従来困難となる無絶縁コイルシステムの設計及び特性評価ができるようになった。また，銅ピックアップコイルと可変抵抗に基いた常伝導転移検出及び保護法は，常電導転移事故時に超伝導コイルシステム内に蓄えた電磁エネルギーの引出しを制御できるようになった。