Field measurement for superconducting magnets of ADS injector Ⅰ

A superconducting magnet prototype for Accelerator Driven Sub-critical System Injection-Ⅰ had been designed and fabricated, and tested in a new made vertical Dewar in November 2012. Batch magnet production was processed after some major revision from the magnet prototype, they include: removing off the perm-alloy shield, extending the iron yoke, using thin superconducting wire, etc. The first one of the batch magnets was tested in the vertical Dewar at the Harbin Institute of Technologyin in September 2013. A field measurement was carried out at the same time by the measurement platform that was seated on the top of the vertical Dewar,the measurement results met the design requirements. This paper will present the field measurement system design, measurement results and discussion on the residual field from the persistent current effect.     

Current leads for superconducting magnets of ADS injector I

In an ADS injector i, there are five superconducting magnets in each cryomodule. Each superconducting magnet contains a solenoid magnet, a horizontal dipole corrector （HDC）, and a vertical dipole corrector （VDC）. Six current leads will tm required to power the electrical circuits, from room temperature to the 2.1 K liquid helium bath： two leads carry 100 A current for the solenoid magnet while the other four carry 12 A for the HDC and the VDC. This paper presents the principle of current lead optimization, which includes the cooling methods, the choice of material and structure, and the issues for current lead integration.     

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.     

利用轴向磁化的永磁环制造轴向梯度磁场

首先叙述了由单个轴向磁化环所产生的磁场,并就两个永磁环所产生的纵向磁场进行了分析.对于两个沿同一方向磁化的永磁体环,沿磁环中心线将会产生一个强度较为均匀的轴向磁场.如果两者的磁化方向相反,则在两磁铁间的区域将产生一个纵向的梯度磁场,其磁场强度介于-B₀到+B₀之间.设计制造了一个高梯度的轴向磁场,其磁场梯度为47.2Tm,测量结果与计算结果非常一致.文中还讨论了产生变梯度磁场的方法.由于永磁环所产生的磁场和螺线管的磁场较为相似,磁铁外部空间将有较大的漏场,最后还讨论了屏蔽漏场的问题.     

BEPC Ⅱ工程磁铁设计与制造

北京正负电子对撞机(BEPC)改造工程是将原来的单环升级为高亮度的双环对撞机(BEPCⅡ),即在现存的BEPC隧道里增加一个新的储存环.使得BEPC Ⅱ能够提供从1.0GeV到2.1GeV能量范围的高亮度对撞束流供高能物理实验用,同时外环还要兼容2.5GeV能量250mA流强的同步辐射专用模式运行,实际上相当于有3个储存环运行.由于受到BEPC储存环隧道空间的局限,物理上的高亮度要求,以及BEPCⅡ真空盒设计采用带前室(Antechamber)结构,因此给各种磁铁设计与制造增加了相当大的难度.着重介绍BEPCⅡ储存环和对撞区中几种主要常规磁铁的设计、制造概况,同时也给出了相应的磁场测量结果.     

加速器驱动次临界系统阶梯场磁铁设计

为保证加速器驱动次临界系统输运线靶站的使用寿命,采用了一种基于阶梯场磁铁的方案将质子束在水平、垂直两个方向进行扩展。对阶梯场磁铁进行了三维磁场模拟和物理设计,根据联合模拟的磁场分布进行了束流动力学跟踪研究,证实阶梯场磁铁方案对均匀化束流有很好的效果。为了使阶梯场磁铁磁场的台阶状分布更加明显,提出了一种更为紧凑的阶梯场磁铁设计方案。     

Physical design of superconducting magnet for ADS injection Ⅰ

A superconducting solenoid prototype magnet for Accelerator Driven Subcritical System (ADS) Injection Ⅰ has been designed and fabricated, which has also been tested in a liquid Helium state inside a vertical Dewar in the Haerbin institute of Technology in November 2012. The design current was 210 A, when the test current reached 400 A no quench occurred so the solenoid magnet was forced to quench by the embedded heaters. The integral field strength, leakage field at the nearby upstream and downstream superconducting spoke cavities all meet the design requirements. At the same time, it also checked the reliability of the vertical test Dewar and the quenched detection system. The superconducting prototype magnet has accumulated valuable experiences for the coming batch magnets production and cryogenic test.     

亥姆霍兹线圈测量系统的测量原理及程序设计

叙述了利用磁通法建立亥姆霍兹线圈测量系统的测量原理,并将其应用于永磁体磁性能参数(Br,Hc,易磁化轴方向等)的测量.在利用现有高性能积分器的基础上,还给出了测量程序的设计方法,并利用此测量系统对BEPC永久四极磁铁模型所用磁块进行了测量.最后,就由于亥姆霍兹线圈机械偏差所带来的测量误差进行了讨论.     

Current leads for superconducting magnets of ADS injector Ⅰ

In an ADS injector Ⅰ, there are five superconducting magnets in each cryomodule. Each superconducting magnet contains a solenoid magnet, a horizontal dipole corrector (HDC), and a vertical dipole corrector (VDC). Six current leads will be required to power the electrical circuits, from room temperature to the 2.1 K liquid helium bath: two leads carry 100 A current for the solenoid magnet while the other four carry 12 A for the HDC and the VDC. This paper presents the principle of current lead optimization, which includes the cooling methods, the choice of material and structure, and the issues for current lead integration.     

BEPCⅡ工程磁铁设计与制造

北京正负电子对撞机(BEPC)改造工程是将原来的单环升级为高亮度的双环对撞机(BEPCⅡ), 即在现存的BEPC隧道里增加一个新的储存环. 使得BEPCⅡ能够提供从1.0GeV到2.1GeV能量范围的高亮度对撞束流供高能物理实验用, 同时外环还要兼容2.5GeV能量250mA流强的同步辐射专用模式运行, 实际上相当于有3个储存环运行. 由于受到BEPC储存环隧道空间的局限, 物理上的高亮度要求, 以及BEPCⅡ真空盒设计采用带前室(Antechamber)结构, 因此给各种磁铁设计与制造增加了相当大的难度. 着重介绍BEPCⅡ储存环和对撞区中几种主要常规磁铁的设计、制造概况, 同时也给出了相应的磁场测量结果.