| 摘要 |
An apparatus which permits high-angle annular dark-field (HAADF) imaging comprises an electron gun, a specimen chamber in which a specimen is set, a gas cylinder for supplying environmental gas around the surface of the specimen through both a gas flow rate controller and a gas nozzle, a vacuum pump for evacuating the inside of the specimen chamber, an objective lens including upper and lower polepieces, a detector for detecting electrons transmitted through the specimen, a display device for displaying a transmission image of the specimen, orifice plates having minute holes, holders supporting the orifice plates, a drive mechanism for driving the holders, and a motion controller. The orifice plates can be moved in a direction crossing the optical axis of the beam on the upper and lower surfaces of the upper and lower polepieces of the objective lens.
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