| 摘要 |
A detector for scanning electron microscopes with high pressure in the sample chamber has a first electrode for accelerating electrons emergent from a sample received on the sample holder, and at least one second electrode, the end of which directed toward the sample holder is at a smaller distance from the sample holder than the first electrode, and is at a potential between the potential of the first electrode and the potential of the beam guiding tube. The volume of the secondary electron cascade is increased by the second electrode. In an alternative embodiment for a gas scintillation detector, there is adjoined to a region of high secondary electron amplification, an elongate region in which the amplification factor for secondary electrons is approximately 1. The first region serves for the production of a relatively large electron current and the second, elongate, region for the production of a strong photon signal while maintaining the photon current.
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