| 摘要 |
In an electron beam interference system using an electron biprism, which is capable of independently controlling each of the interference fringe spacing s and the interference width W, both of which are important parameters for an interferometer and for an interferogram acquired by the interferometer, an optical system used in a two-stage electron biprism interferometer is adopted. The optical system uses two stages of electron biprisms in an optical axis direction to give the flexibility to the relative magnification relative to a specimen image and that relative to an image of a filament electrode of the electron biprism. In addition, as a two-stage configuration in which two objective lenses (51, 52) are combined, independently controlling the focal length of each objective lens makes it possible to set the relative magnification relative to a specimen image and that relative to an image of the filament electrode of the electron biprism at arbitrary values.
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