摘要
中国科学院近代物理研究所正在研发第四代ECR(电子回旋共振)离子源FECR(first 4th generation ECR ion source).以20 kW/45 GHz微波加热运行为目标,需要研制Nb_(3)Sn超导磁体以实现对所加热等离子体的有效磁场约束.作为首台采用Nb_(3)Sn超导磁体技术的ECR离子源,FECR的主磁场线圈由4套独立的轴向螺线管线圈与1套径向六极线圈所构成,且均采用单股Nb_(3)Sn线绕制而成,这给线圈的加工、冷体装配、磁体的失超保护等环节带来一系列挑战.为使磁体能在高场、高应力作用下安全稳定运行,项目采用基于铝壳体结构与bladder&key的预紧应力控制技术,完成了一套半尺寸冷体样机的研发.该样机已完成4.2 K低温测试.本项研究的核心关键问题与挑战是如何在复杂的高精度机械装配与高电流强磁场励磁过程中实现对易碎Nb_(3)Sn导线的有效保护.本篇文章中,我们将阐述如何设计、研制、装配及测试工作于复杂磁场与应力环境的高性能Nb_(3)Sn六极磁铁.针对于单个六极线圈的测试,我们设计研发了一种称为“Mirror”结构的测试工装.论文中会详细论述基于壳层结构与bladder&key的装配预紧技术在半尺寸样机上的应用效果.同时,论文对在半尺寸样机上观察到的强烈磁通跳跃现象和它对失超探测保护的严峻挑战问题及相关解决或规避方案进行相关论述.
A 4th generation ECR(electron cyclotron resonance)ion source FECR(first 4th generation ECR ion source)is under construction at IMP(Institute of Modern Physics).Aiming to be operated with the microwave power of 20 kW at 45 GHz,a fully superconducting Nb_(3)Sn magnet is to be developed to realize the optimum ECR plasma confinement.As the first superconducting ECR magnet that utilizes single-strand Nb_(3)Sn(niobium three tin)wire for the winding of coils consisting of 4 sets of axial solenoids and one sextupole,it poses many challenges in the coil fabrication,cold mass assembly,magnet quench protection,and so on.With a shell-based structure and bladder-and-key technology,we have completed a 1/2-length FECR cold mass prototype.It has been fully tested when immersed in 4.2 K liquid helium.The critical issue in this work is to keep the brittle Nb_(3)Sn wire safe during the complicated mechanical process and protect it against the high current high magnetic field excitation.In this paper,we will report on the details of how to design,fabricate,assemble,and test a high-performance Nb_(3)Sn sextupole with the existence of sophisticated magnetic fields and stresses.The successful test of a high-current sextupole coil in a so-called mirror structure will be reported.The application of the bladder-and-key structure to the prototype and the performance will be presented.This research has also tackled the solutions to mitigate very intense flux jump that has caused severe challenges to quench detection and protection.
作者
孙良亭
吴巍
吴北民
陈玉泉
朱丽
欧贤金
郑石钧
梅恩铭
关明智
辛灿杰
王旭东
卢旺
任文辉
赵红卫
Liangting Sun;Wei Wu;Beimin Wu;Yuquan Chen;Li Zhu;Xianjin Ou;Shijun Zheng;Enming Mei;Mingzhi Guan;Canjie Xin;Xudong Wang;Wang Lu;Wenhui Ren;Hongwei Zhao(Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou,730000,China;School of Nuclear Science and Technology,University of Chinese Academy of Sciences,Beijing,100049,China;Advanced Energy Science and Technology Guangdong Laboratory,Huizhou,516000,China)
基金
the National Natural Science Foundation of China(Grant Nos.11427904,12025506,and 12172357)
the Key Scientific Instruments Development Program of CAS(Grant No.GJJSTD20210007)
the Key Projects of Guangdong Basic and Applied Basic Research Fund Joint Fund(Grant No.2022B1515120051).
