| 摘要 |
PROBLEM TO BE SOLVED: To realize a scanning electron microscope, in which secondary electrons can be detected even under a low vacuum, and an observation of a secondary electron image can be performed. SOLUTION: By a differential evacuation of a sample room and a corona ring room 16, where a corona ring 10 has been positioned, to make a degree of vacuum in a corona ring room higher, a sufficient voltage to accelerate the secondary electrons can be applied to the corona ring 10 without generating an electrical discharge. As a result, the secondary electrons that are generated by their radiation of an electron beam EB to the sample are collected by a collector 9 where voltage of 300 V has been applied, and they are collected in the vicinity of a central opening of a collector throttling 17 by an electric field of the collector throttling 17 where higher voltage than the collector potential has been applied. The collected secondary electrons are accelerated by the corona ring 10, and they collide with a scintillator 21.
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