Magnetic shimming schemes for a six-row permanent magnet based helical undulator

IF 1.4 3区物理与天体物理 Q3 INSTRUMENTS & INSTRUMENTATION

Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment Pub Date : 2026-06-01 Epub Date: 2026-02-05 DOI:10.1016/j.nima.2026.171366

Zilin Chen , Xiaoyu Li , Qing Guo , Hui Zhao , Zhouyu Zhao , Shutao Zhao , Wan Chen , Heting Li , Xiangchen Yang , Yuhui Li

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引用次数: 0

Abstract

During the tuning of the six-row magnetic array helical undulator's magnetic field, key challenges of gap dependence and X-position dependence are addressed. For gap dependence, the target parameters are the RMS deviations of the second-order field integrals (

R M S I 2 x

R M S I 2 y

). Adjusting pole heights alone is proved insufficient. A solution is implemented by magnetic shimming on the poles and utilizing a staggered shimming concept on

B x

magnetic blocks. This successfully controls both

R M S I 2 x

and

R M S I 2 y

within 2000 Gs cm² across the entire working gap range. For X-position dependence across a ±13 mm range, the focus is on the first/second-order integrals and multipole fields at the outlet. The limited longitudinal space makes magic fingers alone inadequate for compensation. Therefore, two configurations of shimming are introduced to pre-compensate for the dependence, followed by final adjustments with magic fingers. This hybrid approach effectively reduces multipole fields and corrects for defects in the off-axis field.

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六排永磁螺旋波动器的磁摆振方案

在六排磁阵列螺旋波动器磁场调谐过程中，解决了间隙依赖和x位置依赖的关键问题。对于间隙依赖，目标参数是二阶场积分的均方根偏差（RMSI2x & RMSI2y）。单靠调整杆高是不够的。一种解决方案是通过磁极上的磁调光和利用Bx磁块上的交错调光概念来实现的。这成功地控制了RMSI2x和RMSI2y在整个工作间隙范围内2000g cm2。对于±13 mm范围内的x位置依赖性，重点放在出口的一/二阶积分和多极场上。有限的纵向空间使得魔术手指本身不足以补偿。因此，引入了两种调光配置来预先补偿依赖，然后用魔指进行最后的调整。这种混合方法有效地减小了多极场，修正了离轴场中的缺陷。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment 物理-光谱学

CiteScore

3.20

自引率

21.40%

发文量

787

审稿时长

1 months

期刊介绍： Section A of Nuclear Instruments and Methods in Physics Research publishes papers on design, manufacturing and performance of scientific instruments with an emphasis on large scale facilities. This includes the development of particle accelerators, ion sources, beam transport systems and target arrangements as well as the use of secondary phenomena such as synchrotron radiation and free electron lasers. It also includes all types of instrumentation for the detection and spectrometry of radiations from high energy processes and nuclear decays, as well as instrumentation for experiments at nuclear reactors. Specialized electronics for nuclear and other types of spectrometry as well as computerization of measurements and control systems in this area also find their place in the A section. Theoretical as well as experimental papers are accepted.