用于高场加速器磁体的新型高温超导内插线圈概念设计

中国科学院高能物理研究所正在进行环形正负电子对撞机-超级质子对撞机(CEPC-SPPC)的研究工作,未来超级质子对撞机(SPPC)初期要求的主环二极磁体磁场强度为12 T,升级后的磁体场强需求为20～24 T.为了达到15 T及以上的场强,高温超导线材制作的内插高场线圈是目前的唯一选择.本文对YBCO内插线圈做了相应的探究,并提出的一种新的设计方案,具有以下特点:线圈结构采用Common-coil与Block-type混合的设计,并解决了端部弯曲半径小的问题;充分利用YBCO在高场下磁场与超导带材平行时临界电流密度是垂直情况下的数倍特性,通过优化端部结构减小线材与磁场夹角;计算了不同形状及弯曲半径组合下的线材弯曲情况,综合考虑了端部长度与线材张力之间相互制约的问题,并给出了最终结果;试绕了两种端部的铜线圈,以及balloon-end的高温超导YBCO线圈并进行了测试.

Design of a High Field YBCO Coil with a New End Structure

IHEP (TheInstitute of High Energy Physics, Chinese Academy of Sciences) is pursuing the pre-study of SPPC, which requires dipole magnets with 12 T in the first step and 20-24 T in the second step. To obtain12 T or higherfield, high temperature superconductor ( HTS) insert coil is the only choice now. Research on the new design of the insert coil with YBCOis reported in this paper, which has three characteristics. 1 ) A coil with both Common-coil and Block-type structure solves the problem of a small bending radius. 2 ) To take advantage of the high critical current in the YBCO tapes in parallel magnet field, which is 3-5 times of that in vertical field, an optimization of end structure is adopted.3) With the calculation of the bending strain in different shapes and bending radius, a result was finally given outconsidering the total length of the end and the strain in the tape.4)Two kinds of end were fabricated with copper and a balloon-end YBCO coil has been fabricated andtested.