Design of Racetrack Coils for High Field Dipole Magnets - eScholarship
Design of Racetrack Coils for High Field Dipole Magnets - eScholarship
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DOI：
10.1109/77.920315
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发表时间：
2001-03
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通讯作者：
G. Sabbi
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作者：
G. Sabbi
LBNL #45139 SC-MAG 702高场偶极磁体的轨道线圈设计G. Sabbi，S. Caspi，S.A.古尔莱河Hafalia，A.杰克逊，A.作者声明：A.斯坎兰湾LBNL的磁体组目前正在开发用于未来对撞机的高场加速器磁体。主要的挑战之一是提供一种设计，该设计具有成本效益并且制造简单，同时导致良好的训练性能和适合加速器操作的场地质量。最近的研究集中在具有简单和导体兼容性优点的跑道几何形状上。研究结果已应用于一系列基于Nb 3Sn导体的原型高场磁体的设计。线圈模块铁轭键1.一项为未来对撞机开发高场加速器磁铁的计划正在美国的几个实验室进行。在完成13.5 T cos-8偶极D-20 [1]之后，LBNL磁体组开始研究最近提出的双孔壳体的通用线圈配置（图1）。RD-3横截面。偶极子，使用两个磁孔之间共享的跑道线圈[2][3]。第一次测试涉及使用ITER型Nb，Sn导体建造的6 T短模型（RD-2）。磁体达到短样本场，没有在各种配置中进行训练[4J.该系列中的以下磁铁（RD-3）使用高性能Nb 3 Sn导体，在12 T、4.2 K下临界电流密度高于2 kA/mm 2，设计电流密度可达14 T [5 J.线圈结构由两个外模块和一个内模块组成。两个外部模块已经在背靠背配置（RT-1）中进行了预测试，并且已经实现了12 T的场[6]。现在，整个结构已经组装完毕，测试正在进行中。目前的实验主要集中在基本的结构是- II。设计要求图1显示了RD-3偶极子的横截面。磁铁有三个主要组成部分。第一组件包括3个线圈模块，围绕铁芯（岛）缠绕。对于每个模块，垂直预载由焊接到侧轨的面板（蒙皮）提供。第二个组件是铁轭，它作为磁通返回。第三个组件是外部铝壳，它提供了对大的水平力的支持。轭架在内部衬垫和外部结构之间分开。使用加压囊系统（PBS）将键插入所得间隙中，以在室温下达到所需的预应力[7]。两个孔件，每个提供一个10毫米的通光孔径，被插入到新的配置和制造技术的发展之间。该计划下一阶段的目标是实现适合高能对撞机操作的场质量，同时保持最高水平的简单性和效率。本文提出了一个实验方案的要求清单，并描述。一系列的原型磁铁，正在设计，以满足这些要求。2000年9月18日收到Mandarin pt。作者是劳伦斯伯克利国家实验室，一个塞- clotron路，伯克利，CA 94720.这项工作得到了美国能源部的支持。线圈。磁体计划下一阶段的第一个要求是将净孔直径从10 mm增加到40 mm。应该注意的是，通过将未来对撞机的磁体孔径降低到比现有机器更低的值，可以实现显著的成本节约。跑道配置特别适合于制造小孔径偶极子。初步研究表明，可以使用0.7 mm股线制造线圈间距为20 mm的跑道磁体，所有谐波均在14 mm直径的圆内的一个单元内（线圈间距的2/3）[8 J.然而，首先必须证明，高场
LBNL#45139 SC-MAG 702 Design of Racetrack Coils for High-Field Dipole Magnets G. Sabbi, S. Caspi, S.A. Gourlay, R. Hafalia, A. Jackson, A. Lietzke, A.D. McInturff, R.M. Scanlan Ab.'Jtract- The magnet group at LBNL is currently in the process of developing high-field accelerator magnets for use in future colliders. One of the primary challenges is to provide a design which is cost-effective and simple to manufacture, at the same time result- ing in good training performance and field quality ad- equate for accelerator operation. Recent studies have focused on a racetrack geometry that has the virtues of simplicity and conductor compatibility. The results have been applied to the design of a series of prototype high-field magnets based on Nb3Sn conductor. Coil Modules Iron Yoke Keys 1. INTRODUCTION Iron Pole A program to develop high-field accelerator magnets for future colliders is underway at several U.S. laboratories. After completion of the 13.5 T cos-8 dipole D-20 [1], the LBNL magnet group has started to investigate a recently proposed common coil configuration for two-aperture Shell Fig. 1. RD-3 cross-section. dipoles, using racetrack coils shared between both mag- net apertures [2J [3J. The first test involved a 6 T short model (RD-2) built using ITER-type Nb,Sn conductor. The magnet reached short sample field with no training in a variety of configurations [4J. The following magnet in this series (RD-3) uses high-performance Nb 3 Sn con- ductor with critical current density above 2 kA/mm 2 at 12 T, 4.2 K, and is designed to reach 14 T [5J. The coil structure is composed of two outer modules and one in- ner module. The two outer modules have been pre-tested in back-to-back configuration (RT-l) and have achieved a field of 12 T [6J. The complete structure is now assembled and testing is underway. Present experiments are focused on basic structural is- II. DESIGN REQUIREMENTS Fig. 1 shows a cross-section of the RD-3 dipole. The magnet has three major components. The first compo- nent comprises 3 coil modules wound around iron cores (islands). For each module, vertical pre-load is provided by face plates (skins) welded to side rails. The second component is the iron yoke, which serves as a flux return. The third component is the outer aluminum shell, which provides support against the large horizontal forces . The yoke is split between an inner pad and an external struc- ture. Keys are inserted in the resulting gap using a Pres- surized Bladder System (PBS) to reach the desired pre- stress at room temperature [7J. Two bore pieces, each one providing a 10 mm clear aperture, are inserted between sues and the development of fabrication techniques for the new configuration. Goal for the next phase of the program is to achieve field quality suitable for operation in high-energy colliders while retaining the highest level of simplicity and efficiency. This paper presents a list of requirements for the experimental program, and describes . a series of prototype magnets which are being designed to satisfy these requirements. Manuscript received September 18, 2000. Authors are with Lawrence Berkeley National Laboratory, One Cy- clotron Road, Berkeley, CA 94720. Work supported by the U.S. Department of Energy. the coils. The first requirement for the next phase of the magnet program is to increase the clear bore diameter from 10 mm to 40 mm. It should be noted that significant cost sav- ings can be realized by decreasing the magnet aperture of future colliders to lower values than in present machines . The racetrack configuration is particularly well suited to fabrication of small-aperture dipoles. Preliminary studies indicate that a racetrack magnet with coil to coil spac- ing of 20 mm can be fabricated, using 0.7 mm strand, with all harmonics well within one unit within a circle of 14 mm diameter (2/3 of the coil to coil spacing) [8J. How- ever, it is first necessary to demonstrate that a high-field