Magnetic lens system for electron microscope - has adjusting system for angular variations of axial alignment of magnetic field coils

摘要

The lens system has a current coil and has two screening cylinders of coaxial arrangement. The screening cylinders are of superconductive material and have bore for the passage of the electron beam. They are in thermal contact with cryogenic substance, as in 1564714. The cylinder faces are spaced, and the gap is free of screening. The gap is rated for a minimum opening fault constant. The electron beam passage bore diameter is kept at the minimum required value. In order to change the angle of the axial alignment of the lens coils (3), adjusting elements are provided effective relative to the axis (11) of symmetry of the lens system. The adjusting elements are preferably in the form of screws radially distributed over the circumference of the coil to be adjusted, these screws being adjustable independently.