| 摘要 |
PURPOSE:To provide a method, by which the Kossel line can be photographed clearly for the shortest time period even for a fine or remarkably fine region of a sample, by tapering the open edge of the aperture of an electronic optical system in the vicinity of the sample so that it may be sharpened. CONSTITUTION:By the use of the construction including a filament 1, a Wehnelt electrode 2, a condenser lens 3, an objective lens 4, a deflecting coil 6 and a detector, an image of a scanning type electronic microscope is formed on display Brown tubes 8 and 8'. The object on a sample surface 5 is detected by the electronic microscope image and is aligned with the optical axis of the electronic optical system. Then, the sweeping operation of the electron beam is stopped, and a cassette is positioned below the sample 5 so that it is subjected to exposure for a preset time. Then, a next cassette is moved to a photographing position. In these ways, the Kossel images of the object are consecutively photographed. One C of apertures A, B and C is tapered at its both sides to sharpen the open edge. Thus, it is possible to produce an electron beam which is excellent in covergence while enlarging the sample current. |
