Deflector plates are one of the critical components in ultrafast electron microscope (UEM), which generates the short electron pulse. While the electron pulse can be stretched due to the velocity dispersion induced by the fringe field of the deflector plates, understanding the effect of the fringe field on the electron velocity and how to avoid the adverse effect of it are needed in the design of the deflector plates. In this paper, firstly, an analytical model of the fringe field of deflector plates with double field input is given. This analytical model can be adapted to other new designs with different double field inputs, and as an example, the velocity dispersion, stretched time, and energy gain of an electron pulse are calculated with a linear double field input. Secondly, three sets of particle tracing simulations on electron velocities have been studied in terms of different single field inputs. The simulated results show that the longitudinal velocity of the electron changes very differently as a result of the different voltage sign on the deflector plates. In our model, the longitudinal velocity is almost constant until the electron leaves the deflector plates. So the results suggest that the deflector plates with double field input are recommended not only in UEM setups but also in other charged particle beam setups where needs high deflection accuracy.

中文翻译：

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超快电子显微镜中偏转板边缘场效应的分析与仿真。

偏转板是超快电子显微镜（UEM）的关键组件之一，它会产生短电子脉冲。尽管由于偏转板边缘场引起的速度色散可以使电子脉冲拉伸，但是在设计偏转板时需要了解边缘场对电子速度的影响以及如何避免它的不利影响。盘子。本文首先给出了具有双场输入的偏转板边缘场的解析模型。该分析模型可以适应具有不同双场输入的其他新设计，例如，使用线性双场输入计算电子脉冲的速度色散，拉伸时间和能量增益。其次，根据不同的单场输入，研究了三组关于电子速度的粒子追踪模拟。模拟结果表明，由于偏转板上不同的电压符号，电子的纵向速度变化非常不同。在我们的模型中，纵向速度几乎恒定，直到电子离开偏转板。因此，结果表明，不仅在UEM装置中，而且在需要高偏转精度的其他带电粒子束装置中，都建议使用带双场输入的偏转板。纵向速度几乎恒定，直到电子离开偏转板。因此，结果表明，不仅在UEM装置中，而且在需要高偏转精度的其他带电粒子束装置中，都建议使用带双场输入的偏转板。纵向速度几乎恒定，直到电子离开偏转板。因此，结果表明，不仅在UEM装置中，而且在需要高偏转精度的其他带电粒子束装置中，都建议使用带双场输入的偏转板。