Electron microscope adjusting system - uses magnetic pole associated with electric coil which controls its pole magnetising

摘要

The adjusting system is intended for electron microscopes and other particle beam apparatus, in which the electron beam is corrected by magnetic fields generated by permanently magnetisable magnetic poles. Each magnetic pole (1-4) of the electron microscope is allocated to an electric coil (11-14) which controls the permanent magnetising of this pole owing to the current flow regulation through the same. Preferably each magnetic pole is provided with a pole shoe. This system obviates mechanically displaceable pole shoes and does not require continuously flowing current for its operation. The system is compact and the component rating is sufficient for generation of a field strength suitable for the electron beam correction.