Quench stabilities of the superconducting wires for the sector magnets of RIKEN superconducting ring cyclotron

Abstract

Results of numerical and experimental studies on the quench stabilities of the superconducting coils are described. One of the basic design concepts for the sector magnets is to make quench-free superconducting coils to assure the reliable long period operation of the Superconducting Ring Cyclotron (SRC). For this purpose, it was decided that partial stabilization criteria were used for the main coils, and full stabilization criteria for the trim coils. The stabilization currents of the main and trim wires were calculated by using measured data on characteristics of heat flux transport from the superconducting wires to liquid helium and on electric resistivities of the aluminum stabilizers of the wires. Numerical calculations were done to understand the real transient phenomena and to obtain the capacity and arrangement of electric heaters and voltage taps for experimental study. The experimental study has been done by using small superconducting test coils for the main coil and trim coil. The stabilizing currents obtained from the experiment were 5,700 A and 630 A, respectively.

超伝導コイルのクエンチ安定性に関する数値的および実験的研究の結果を述べた。セクタ電磁石に対する基本的設計概念の1つは超伝導リングサイクロトロン(SRC)の信頼性のある長期運転を保証するようなクエンチフリーな超伝導コイルを造ることである。この目的に対し、主コイルには部分安定化規準を用い、トリムコイルには全安定化規準を用いることに決めた。超伝導線から液体ヘリウムへの熱束輸送特性および超伝導線のアルミニウム安定化材の電気抵抗率の測定データを使って、主およびトリム線の安定化電流を計算した。実際の過渡現象を理解し、実験的研究のための電熱器と電圧タップの容量と配列を得るために数値計算を行った。実験的研究は主コイルとトリムコイルのテスト用の小さな超伝導コイルを使って行った。実験から得た安定化電流は、それぞれ5,700Aと630Aであった。