| 摘要 |
An energy filter, particularly for electron microscopes, in which the setting of different energy bandwidths takes place electron-optically. For this purpose, one or more deflecting systems and one or more transfer lenses are provided at the filter exit. A diaphragm arrangement is arranged in the dispersion plane and has an opening with a stepped edge region. Slit diaphragms with different slit lengths can be simulated by deflection of the electron beam. The deflection of the electron beam effected by the dispersion system(s) perpendicularly to the dispersive direction of the filter is compensated again by a succeeding transfer lens or a further deflecting system, so that an image displacement is also compensated. In a second embodiment, a respective slit edge is arranged in two mutually conjugate spectrum planes. A deflecting system preceding each slit edge, different spectrum portions are filtered out by the two slit edges, according to the excitation of the deflecting systems. The energy bandwidth can be varied continuously in this embodiment.
|
