The Effect of the Geometrical Shape and Position of the Coil on the Optical Performance for Asymmetrical Magnetic Lens

Asymmetrical excited single pole magnetic lens has been designed, using different geometrical coils of equal areas and at different positions with respect to the lens pole.
The objective focal properties and its resolution were calculated. It was found that the geometrical shape of the coil and its position play an important role for exciting the lens pole.
It was noticed that the lens L4 at constant excitation (NI=20 kA-t) shows better results in comparison with the other lenses.