الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
An analytical study is made for appropriate extraction system design. It is found that the extraction through two parallel plane electrodes gives a divergent beam. This divergence effect can be avoided by using a shaped electrode with appropriate geometry such as Pierce electrode which makes the beam nearly parallel. Lastly, a study is made on the spherical design of the extraction electrode. It is found that the beam is focused to a minimum radius (beam waist) located at a distance equal to the focal length of the spherical extraction electrode.