Phase contrast electron microscope with ring-shaped illumination aperture

摘要

The microscope has an annular phase-shifting unit (9) with a central aperture (19) to confer a phase shift of pidivide2 on a null beam. Radiation of higher diffraction orders diffracted at the object in optical axis direction passes through the aperture. An annular illuminating aperture is produced by a deflection system (4) that produces a beam tilt in a conjugate object plane.