Patent Number: 062394304
Section: abstract

A particle beam apparatus that can be used, in particular in an electron microscope, has a dispersively imaging energy filter in the illumination beam path. A higher energy sharpness of the particles contributing to the further particle-optic imaging, and hence a reduction of the effect of chromatic aberrations, is attained by means of the energy filter. So that voltage fluctuations of the applied high voltage also bring about no drift of the image of the beam producer in spite of the dispersion present after complete passage through the filter, the beam producer is imaged, enlarged, in a plane of the filter that is imaged achromatically by the filter into an output image plane. Because of the high dispersion of the dispersive filter as against non-dispersive filters, the particle beam apparatus can be operated at a higher particle energy within the filter, so that the influence of the Boersch effect is reduced in comparison with non-dispersive filters.