Beam-based alignment for the LCLS FEL undulator
Beam-based alignment for the LCLS FEL undulator
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DOI：
10.1016/s0168-9002(99)00117-5
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发表时间：
1999-06-11
影响因子：
1.4
通讯作者：
Huhn, HD
中科院分区：
文献类型：
--
作者：
Emma, P;Carr, R;Huhn, HD
直线加速器相干光源（LCLS）（LCLS设计研究报告，SLAC-R-521，1998）是一种X射线自由电子激光器的基础上，长，永磁体波荡器组成的多个部分，提供空间的电子束位置监测器（BPM）和四极聚焦磁铁。波荡器内的15 GeV电子轨迹必须是直的，在11米的增益长度上近似于5 μ m，使得光子束与电子束有效地重叠。用现有的机械测量方法无法达到这种对准精度。出于这个原因，开发了一种经验性的基于束的对准技术，该技术使用BPM读数结合电子能量中的大的、故意的变化。我们在这里描述了一个详细的对准模拟，包括BPM和磁铁移动校准误差，四极梯度误差，和偶极场误差，这表明可以实现高置信度的对准。(C)1999 Elsevier Science B. V.保留所有权利。
The linac coherent light source (LCLS) (LCLS Design Study Report, SLAC-R-521, 1998) is an X-ray FEL based on a long, permanent magnet undulator comprised of multiple segments which provide space for electron beam position monitors (BPMs) and quadrupole focusing magnets. The 15 GeV electron trajectory within the undulator must be straight to similar to 5 mu m over a gain length of 11 m so that the photon beam overlaps efficiently with the electron beam. This alignment precision is not achievable with available mechanical survey methods. For this reason, an empirical beam-based alignment technique is developed that uses BPM readings in conjunction with large, deliberate variations in the electron energy. We describe here a detailed alignment simulation including BPM and magnet-mover calibration errors, quadrupole gradient errors, and dipole field errors which demonstrate that the alignment can be achieved with high confidence. (C) 1999 Elsevier Science B.V. All rights reserved.