Preliminary Design of the Recombination Dipole for Future Circular Collider
Preliminary Design of the Recombination Dipole for Future Circular Collider
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DOI：
10.1109/tasc.2019.2892725
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发表时间：
2019-01
影响因子：
1.8
通讯作者：
A. Pampaloni;A. Bersani;B. Caiffi;P. Fabbricatore;S. Farinon;A. Ricci
中科院分区：
文献类型：
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作者：
A. Pampaloni;A. Bersani;B. Caiffi;P. Fabbricatore;S. Farinon;A. Ricci
未来圆形对撞机 (FCC) 项目旨在产生后大型强子对撞机 (LHC) 粒子对撞机的概念设计，能够在质子-质子和电子-电子配置中达到更高的光束能量和更高的亮度。在质子-质子配置中，FCC 必须能够在 100 公里隧道中循环 50 GeV 质子。该项目的关键作用是超导磁体的研发，超导磁体必须能够产生明显高于大型强子对撞机的磁场。除了必须产生 16 T 场的弯曲偶极子之外，相互作用区域中的多重态也代表了技术挑战：例如，复合偶极子预计会产生 10 T 场，因此必须使用 Nb3Sn。在这篇文章中，将详细介绍 FCC 双孔径复合偶极子的初步设计。它采用两层余弦-θ 设计，以便在孔中产生所需的 10 T 场。两个孔径中的磁场方向相同，产生不可忽略的串扰，使用不对称线圈可将串扰降至最低。将描述磁性设计，重点关注 Nb3Sn 导体的主要特征。绕组配置和铁轭形状已经过优化，以实现合适的磁场质量。还将提出机械设计的解决方案：必要的预应力将通过所谓的“囊和键”概念给出，这避免了轴环，并且由于部件的不同热收缩，当 Nb3Sn 脆性较小时，可以在冷却后获得大部分预应力。所提出的解决方案从磁性角度（即磁场质量和电流裕度）和机械角度满足所有标准要求，在所有磁体操作期间具有可行的结构方案以及对导体和支撑结构的相当低的应力。
The Future Circular Collider (FCC) project aims at producing a conceptual design of a post-Large Hadron Collider (LHC) particle collider, able to reach higher beam energy with higher luminosity both for proton–proton and electron–electron configurations. In the proton–proton configuration, the FCC must be able to circulate 50 GeV protons in a 100 km tunnel. A key role in this project is played by the R&D on superconducting magnets, which must be able to produce magnetic fields significantly higher than in the LHC. Beside the bending dipoles, which must produce a 16 T field, also the multiplets in the interaction regions represent a technological challenge: as an example, the recombination dipoles are expected to produce a field of 10 T and therefore Nb3Sn must be used. In this contribution, the preliminary design of a double aperture recombination dipole for the FCC will be presented in details. It features a two layers, cosine–theta design, in order to produce the required field of 10 T in the bore. The magnetic field has the same direction in both apertures, generating a not negligible crosstalk which is minimized using asymmetric coils. The magnetic design will be described, focusing on the main features of the Nb3Sn conductor. The winding configuration and the iron yoke shape have been optimized to achieve a suitable field quality. A solution for the mechanical design will also be presented: the necessary prestress will be given by the so-called “bladder and keys” concept, which avoids the collaring and allows to obtain, thanks to differential thermal contraction of the components, most of the prestress after the cool down, when the Nb3Sn is less brittle. The proposed solution fulfills all the standard requirements both from the magnetic point of view, i.e., field quality and current margin, and from the mechanical one, with a viable construction schema and reasonably low stress on conductor and support structures, during all the magnet operations.