Beam dynamics aspects of crab cavities in the CERN Large Hadron Collider
Beam dynamics aspects of crab cavities in the CERN Large Hadron Collider
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CERN 大型强子对撞机中蟹腔的束流动力学方面
DOI：
10.1103/physrevstab.12.101002
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发表时间：
2009
影响因子：
--
通讯作者：
F. Zimmermann
中科院分区：
文献类型：
--
作者：
Yipeng Sun;A. Morita;R. Calaga;J. Barranco;R. Assmann;T. Weiler;R. Tomás;F. Zimmermann
现代对撞机将大量的束团带入碰撞中，以实现高光度。通过引入一个交叉角，减轻了在这种对撞机上的寄生相遇引起的远距离束流效应。在这些条件下，蟹腔(CC)可以用来恢复有效的迎头碰撞，从而增加几何光度。直线对撞机和圆形对撞机都提出了这样的蟹形腔。蟹形腔是以横向偶极子模式工作的射频腔，它给予束流粒子一个横向踢，该横向踢随着束团的纵向位置而变化。在大型强子对撞机(LHC)中使用蟹形腔不仅会提高束流的光度，而且会使束流动力学复杂化，例如蟹形腔不仅会抵消由交叉角激发的同步电子共振，还可能激发新的共振，它们会缩小非动量粒子的动态孔径，影响孔径和轨道，还会降低准直清洗效率等。本文从束流动力学的角度探讨了大型强子对撞机蟹腔的基本可行性。更多的研究包括动态光圈、光圈和β拍频、发射度增长、光束调谐漂移、远距离碰撞、同步强子共振、光圈色散和准直效率。
Modern colliders bring into collision a large number of bunches to achieve a high luminosity. The long-range beam-beam effects arising from parasitic encounters at such colliders are mitigated by introducing a crossing angle. Under these conditions, crab cavities (CC) can be used to restore effective head-on collisions and thereby to increase the geometric luminosity. Such crab cavities have been proposed for both linear and circular colliders. The crab cavities are rf cavities operated in a transverse dipole mode, which imparts on the beam particles a transverse kick that varies with the longitudinal position along the bunch. The use of crab cavities in the Large Hadron Collider (LHC) may not only raise the luminosity, but it could also complicate the beam dynamics, e.g., crab cavities might not only cancel synchrobetatron resonances excited by the crossing angle but they could also excite new ones, they could reduce the dynamic aperture for off-momentum particles, they could influence the aperture and orbit, also degrade the collimation cleaning efficiency, and so on. In this paper, we explore the principal feasibility of LHC crab cavities from a beam dynamics point of view. The implications of the crab cavities for the LHC optics, analytical and numerical luminositymore » studies, dynamic aperture, aperture and beta beating, emittance growth, beam-beam tune shift, long-range collisions, and synchrobetatron resonances, crab dispersion, and collimation efficiency will be discussed.« less