Simulation of magnetic field shielding plate design for UED electron gun

LI Mengchao; ZHANG Lu; FEI Linbo; CHEN Wei; HUANG Jun; NI WeiYuan; WANG Xingquan

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Simulation of magnetic field shielding plate design for UED electron gun

Optical Devices & System Design | 更新时间：2025-10-09

- Simulation of magnetic field shielding plate design for UED electron gun
- OPTICAL TECHNIQUE Vol. 51, Issue 4, Pages: 456-461(2025)
- 作者机构：
  
  1.赣南师范大学物理与电子信息学院，江西赣州 341000
  2.聊城二中附属东苑中学，山东聊城 252000
- 作者简介：
- 基金信息：
- DOI：
  CLC： O463
- Received：20 February 2025，
  
  Revised：2025-04-03，
  
  Published：20 July 2025
- 稿件说明：
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李梦超,张璐,费林博等.UED电子枪磁场屏蔽板设计仿真[J].光学技术,2025,51(04):456-461.

LI Mengchao,ZHANG Lu,FEI Linbo,et al.Simulation of magnetic field shielding plate design for UED electron gun[J].OPTICAL TECHNIQUE,2025,51(04):456-461.
李梦超,张璐,费林博等.UED电子枪磁场屏蔽板设计仿真[J].光学技术,2025,51(04):456-461. DOI：

LI Mengchao,ZHANG Lu,FEI Linbo,et al.Simulation of magnetic field shielding plate design for UED electron gun[J].OPTICAL TECHNIQUE,2025,51(04):456-461. DOI：

摘要

采用Poisson Superfish联合General Particle Tracer仿真UED直流光阴极电子枪安装不同磁场屏蔽板后的效果。发现磁屏蔽板中心开孔越小，磁场屏蔽效果越好，被屏蔽后的磁场大小与开孔半径成正比。然而当孔太小时，继续减小孔径对屏蔽效果提升不明显。磁屏蔽板厚度越厚，屏蔽效果越好，被屏蔽后的磁场大小与厚度成反比，但厚度变化对屏蔽的提升有限。磁屏蔽板距离电子枪越近，电子枪磁场越大，被屏蔽后的磁场大小与距离成反比，这主要是中心开孔的漏磁导致。磁屏蔽板的存在会导致电子脉冲聚焦提前，聚焦半径变小。电子脉冲聚焦半径和焦距随磁屏蔽板中心孔半径变小而变小，同时随着磁屏蔽板厚度增大而变小。电子脉冲聚焦半径和焦距随磁屏蔽板距离电子枪的距离的增大而变小。总之，磁场屏蔽效果越好，电子枪和磁屏蔽之间的磁场越小，电子脉冲聚焦半径和焦距越小。

Abstract

Poisson Superfish and General Particle Tracer were used to simulate UED DC photocathode electron guns with different magnetic shielding plates. The smaller the center hole of the magnetic shielding plate

the better the magnetic field shielding. The shielded magnetic field is proportional to the aperture radius. Continuing to reduce the hole does not significantly improve shielding

while the central hole is too small. The thicker the magnetic shielding plate

the better the shielding effect

but the improvement is not significant. The shielded magnetic field is inversely proportional to its thickness. The closer the magnetic shielding to the electron gun

the larger the field in the gun

which mainly due to magnetic leakage from the central hole. The shielded magnetic field is inversely proportional to the distance from the cathode. The installation of magnetic shielding plates leads to premature focusing of electronic pulses and a smaller focusing radius. The smaller the center hole in the magnetic shielding plate

the smaller the focusing radius and focal length. The thicker the magnetic shielding plate

the smaller the focusing radius and focal length. The farther the magnetic shielding plate to the electron gun

the smaller the focusing radius and focal length. The better the magnetic field shielding

the smaller the magnetic field between the electron gun and the magnetic shielding

and the smaller the electron pulse focusing radius and focal length

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references

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