| 摘要 |
This invention provides for an improved gaseous detector device for an environmental scanning electron microscope (ESEM). A first electron detector (28) is formed integrally with the pressure limiting aperture (14). A generally annular electrode assembly (36) is positioned slightly below the pressure limiting aperture (14) and includes an inner electron detector (30) in the form of a thin ring, an intermediate electron detector (32) in the form of concentric arc segments (38a, 38b), and an outer electron detector (34) also in the form of concentric arc segments (40a, 40b). An aperture carrier electron detector (42) in the form of a thin ring is positioned above the pressure limiting aperture (14). A control grid (70) is positionable between the detectors (28, 30, 32, 34, 42) and the specimen mount (26) and biased at an electrical potential between the electrical potential applied to the electrodes (28, 30, 38a, 38b, 40a, 40b, 42) and specimen mount (26) so as to increase the acceleration of the signals emanating from the specimen (24). |
