| 摘要 |
An improved gaseous detector device for an environmental scanning electron microscope (ESEM) is provided. The detector device includes a generally annular electrode assembly having an inner electron detector formed of a thin ring, an intermediate electron detector positioned radially outwardly of the inner electron detector which is formed of a first plurality of concentric arc segments, and an outer electron detector positioned radially outwardly of the intermediate electron detector which is formed of a second plurality of concentric arc segments. The first plurality of concentric arc segments is positioned generally normal to the second plurality of concentric arc segments to obtain a directional topographic contrast. The inner, intermediate and outer electron detectors are aligned along generally the same horizontal plane.
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