| 摘要 |
PROBLEM TO BE SOLVED: To allow a focal spot size to be easily changed even if a two-stage type electronic lens is provided by using an imaging confirming target. SOLUTION: An electron beam 12 is focused on a first imaging point 16 by a first electronic lens 14 and the electron beam having passed through it is focused on a main target 20 by a second electronic lens 18. The imaging confirming target 28 can be arranged at the position of the first imaging point 16. When the electron beam impinges on the imaging confirming target 28, an X-ray is generated therefrom and is observed by an observation window with a fluorescent coating applied thereto. While carrying out the observation, an excitation current of the first electronic lens 14 is adjusted. The imaging confirming target 28 can be changed over between an insertion position on the path of the electron beam 12 and an evacuation position deviated from the path of the electron beam 12. The imaging confirming target 28 and the observation window can be moved in a direction (the direction of an arrow 64) along the electron beam 12. COPYRIGHT: (C)2006,JPO&NCIPI
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