Pole piece's properties evaluation of SEM

The various methods of designing the geometry of the columns were announced in lots of papers, because of the extreme importance of understanding accurate field of potential distributions. But such methods can be dealt with only by computer-aided methods. If we are interesting in figuring out the behavior of the entire beam in columns rather than individual trajectories of beam, simply numerical solutions for electron lenses are convenient. These methods don't take aberrations into account. It is easy method to understanding the properties of lens. Our lenses in column consist of two condenser lenses and one objective lens. Tungsten filament is used as beam source. To generate the fringe field, electromagnetic coils are used. Pole piece including sleeve is inserted in electromagnetic coil. Beam goes through the sleeve. We show the configuration of our system, the properties of first condenser lens, lens controller and elements related on beam control. Electron lenses are generally thick lenses, but in here, Lens is dealt as thin lens because of simply modeling and easy understanding.