The effect of polepiece angles for the magnetic electron lens on the aberration coefficients

الملخص EN

The symmetric magnetic objective lens of great importance for the electron microscopes intended for hig resolution.

Such lens is determined ,not only by its geometrieal structure and shape parameters, but also by the influence of the variation of the polepiece angles.

The results show that the Objective lens having the polepiece angle of 55a has a considerable effect on the electron optical Properties .

When this polepiece is appropriately and highly saturated, the lens possesses low spherical and chromatic aberration coefficients.

This hind of polepiece lens leads to more favourable design than other lenses.