OBJECTIVE LENS ASSEMBLY UNIT FOR RASTER ELECTRONIC MICROSCOPE COMMUNICATING WITH ENVIRONMENT AND ITS APERTURE HOLDER Russian patent published in 1995 - IPC

FIELD: electronic microscopes. SUBSTANCE: unit has cylindrical magnetic body of objective lens built up of axially arranged tubular vacuum bush and device for magnetic focusing of electron beam passed through mentioned tubular magnetic bush. Ring made of magnetic material and provided with at least two pump-out holes axially spaced apart abuts mentioned magnetic body at its bottom part. At least two nonmagnetic annular diagrams and terminal annular magnetic diaphragm are attached to ring at different axial points. Diaphragms determine at least two internal channels each communicating with one of pump-out holes formed in ring. Combination aperture holder and electron detector are mounted for removal and sealed in central holes of annular diaphragms. Aperture holder has apertures to pass electron beam and gas into and from chamber for specimens of electronic raster microscope communicating with environment; it also has inner channels and electron detector communicating with bottom section of holder. EFFECT: enlarged functional capabilities. 12 cl, 4 dwg