Emittance growth of bunched beams in bends.
Emittance growth of bunched beams in bends.
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DOI：
10.1103/physreve.51.1453
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发表时间：
1995-02
期刊：
影响因子：
--
通讯作者：
B. Carlsten;T. Raubenheimer
中科院分区：
文献类型：
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作者：
B. Carlsten;T. Raubenheimer
Talman [Phys. Rev. Lett. 56，1429（1986）]提出了一种新的相对论效应，当带电粒子束在来自外部偶极子的磁场中弯曲时发生这种效应。这种效应的结果是，来自粒子的空间电荷力并不表现出通常的平方反比能量依赖性，事实上，它们中的某些部分与能量无关。这导致了这样的猜测，即这种效应可能会导致弯曲电子束的发射度显著增长。随后，它表明，这种效应对梁的横向运动的影响被取消的直流束内的潜在抑郁症的光束（一阶的光束半径除以弯曲半径）。在本文中，我们扩展的分析，包括短束长度（相比束管尺寸），并发现不再有取消的横向和运动方向的力。我们提供了一个估计作为弯曲角，束半径和电流的函数的发射度增长，和磁压缩的电子束团。
Talman [Phys. Rev. Lett. 56, 1429 (1986)] has proposed a novel relativistic effect that occurs when a charged particle beam is bent in the magnetic field from an external dipole. The consequence of this effect is that the space-charge forces from the particles do not exhibit the usual inverse-square energy dependence and some part of them are, in fact, independent of energy. This led to speculation that this effect could introduce significant emittance growth for a bending electron beam. Subsequently, it was shown that this effect's influence on the beam's transverse motion is canceled for a dc beam by a potential depression within the beam (to first order in the beam radius divided by the bend radius). In this paper, we extend the analysis to include short bunch lengths (as compared to the beam pipe dimensions) and find that there is no longer the cancellation for forces both transverse to and in the direction of motion. We provide an estimate for the emittance growth as a function of bend angle, beam radius, and current, and for magnetic compression of an electron bunch.