Generation of precise magnetic fields using high-temperature superconductor magnets for rotating gantry of hadron therapy

2019 Fiscal Year Final Research Report

• Project/Area Number: 16H02326
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Power engineering/Power conversion/Electric machinery
• Research Institution: Kyoto University
• Principal Investigator: Amemiya Naoyuki 京都大学, 工学研究科, 教授 (10222697)
• Co-Investigator(Kenkyū-buntansha): 美舩 健 京都大学, 工学研究科, 講師 (20362460)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 電気機器 / 超伝導電磁石 / 磁場精度 / 遮蔽電流 / 反磁化 / 粒子線がん治療 / 回転ガントリー

Outline of Final Research Achievements

Rotating gantry is needed for carbon cancer therapy. HTS beam-bending magnets, which can generate high magnetic field (4 - 6 T) at relatively high operating temperature (around 20 K) with large temperature margin, enable compact and light-weight rotating gantry. However, we have to suppress the influence of large demagnetization of HTS tapes on the field qualities of magnets. We revealed the electromagnetic phenomena in HTS tapes in magnets through experimental and numerical approaches and clarified how to suppress the influence of magnetization on the field qualities of HTS magnets. We calculated the magnetic field generated by a designed beam-bending magnet, considering the demagnetization of HTS tapes. Based on the calculated magnetic field, we carried out beam-tracking simulation of a rotating gantry consisting of HTS magnets. It showed excellent beam-guiding performance.

Free Research Field

電気工学

Academic Significance and Societal Importance of the Research Achievements

高温超伝導電磁石は高い温度で安定に運転できる点は魅力的であるが、テープ形状をした高温超伝導線の反磁化が磁場精度を劣化させるという問題点がある。複雑な時間パターンで励磁した際の高温超伝導線内部の電磁現象ならびにその磁場精度への影響を明らかにし、高精度な磁場を発生する手法を明らかにした点に本研究の学術的意義がある。また、炭素線がん治療のさらなる普及のために重要な回転ガントリーの格段の小型・軽量化を可能とする技術基盤を構築した点で、その社会的意義も大きい。