Patent ID: 11501947

Abstract:
Provided is an aberration corrector having a plurality of magnetic poles including a first magnetic pole and further magnetic poles, a ring that magnetically connects the plurality of magnetic poles with one another, the ring having a constant spacing to at least the first magnetic pole, a plurality of magnetic field modulators including a first magnetic field modulator and further magnetic field modulators, and a plurality of guides including a first guide and further guides; wherein the first magnetic field modulator includes a soft magnetic material, wherein the first magnetic field modulator is disposed in a first position, the first position being one of the following: adjacent to a first air gap separating the first magnetic pole and the ring, or at an inner ring surface or radially outward of the inner ring surface along an axis of the first magnetic pole, and wherein the first guide constrains the first magnetic field modulator to positions along a first axis substantially parallel to or coincident with the axis of the first magnetic pole.