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GEMINI lens

 

 

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One of the examples of the use of programs is that of GEMINI-type lens, i.e. a combined magnetic-electrostatic SEM lens. The geometry used for the computations is only very very approximate, but it shows well the function of our programs.

The first figure shows the magnetic lens with ”saturation”, i.e. distribution of flux density in iron materials (maximum value close to 0.5 T) and axial flux density (0.04 T for 600 At).

In the bore of the lens, as shown on the second figure, an electrostatic lens is placed, that slows down the electrons, here we suppose from 20 keV to 1 keV energy. 

The trajectories of electrons starting at z=-140 mm with angles 0.5, 1.0 and 1.5 mrad with respect to the axis are shown in the last figure, computed with TRASYS. 

All pictures are just screen copies, the first one from MLD, the second one from ELD, and the last one from SGPLOT.

 

 

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Copyright © 2003 B. Lencova, Software for Particle Optics Computations
Last modified: 30/12/01 16:10