Badin Viktor, Horák Michal, Lencová Bohumila, Zlámal Jakub
Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2, Brno, 616 69, Czechia; Central European Institute of Technology, Brno University of Technology, Purkyňova 123, Brno, 612 00, Czechia.
Central European Institute of Technology, Brno University of Technology, Purkyňova 123, Brno, 612 00, Czechia.
Ultramicroscopy. 2023 Nov;253:113825. doi: 10.1016/j.ultramic.2023.113825. Epub 2023 Aug 1.
The effects of geometrical imperfections in electron-optical components are usually evaluated in 3D simulations. These calculations inherently take a long time, require a large amount of memory, and do not directly produce the necessary axial field functions. We present a 2D perturbation method to calculate parasitic fields in misaligned multipole systems. Our method is based on finding an equivalent potential perturbation, similarly to Sturrock's method, but does not rely on the potential being differentiable. The method is directly applicable to both electrostatic and non-saturated magnetic problems. It does not require any 3D data and it is fully compatible with existing finite element method codes such as EOD. The proposed method produces axial field functions with an accuracy of units to a few tens of percents, depending on the number of unperturbed multipole field components used and the geometry. The results can then be used, for instance, to determine the parasitic imaging aberrations of the misaligned optical system using standard methods, in order to evaluate the effect of mechanical design tolerances.
电子光学元件中几何缺陷的影响通常在三维模拟中进行评估。这些计算本身耗时较长，需要大量内存，并且不会直接产生所需的轴向场函数。我们提出了一种二维微扰方法来计算未对准多极系统中的寄生场。我们的方法基于找到一个等效势微扰，类似于斯特罗克方法，但不依赖于势的可微性。该方法直接适用于静电和非饱和磁问题。它不需要任何三维数据，并且与现有的有限元方法代码（如EOD）完全兼容。根据所使用的未微扰多极场分量的数量和几何形状，所提出的方法产生的轴向场函数的精度在单位到几十百分比之间。然后，这些结果可用于例如使用标准方法确定未对准光学系统的寄生成像像差，以便评估机械设计公差的影响。
