| 摘要 |
PROBLEM TO BE SOLVED: To solve problems of an energy selective filter (10) arranged at a front side of a high-voltage electric field of an electron gun (2) of an electron microscope, transmitting high electric potential, installed in a gun space (14) filled with SF<SB>6</SB>gas, related to electric and mechanical passages, and especially, a centering thereof. SOLUTION: An entrance diaphragm (30) jointed and fixed to a filter component, especially, to a magnetic pole face or a magnetic field demarcating sealing part (48a) of a filter is arranged in order to perform appropriate aperture adjustment to the filter, irrespective of (for avoiding optical aberration generated on a beam caused by current limitation and the filter). COPYRIGHT: (C)2007,JPO&INPIT
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