| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent gas discharge and enable a magnetic field lens to be used as an objective lens of an electron microscope even under an extra-high vacuum by using the magnetic field lens as an objective lens, and by using line material such as a copper wire subjected to coating of such material of small amount of gas discharge. SOLUTION: In an objective lens 2, is used a line material subjected to alumina coating on a copper wire as a coil material for the purpose of being assembled in a ultra-high vacuum. Accordingly, gas discharge can be prevented even though the objective lens 2 is assembled in the ultra-high vacuum. Furthermore, the objective lens 2 has an opening (a) on the sample side of a yoke (semi-in lens). Thus, by determining the configuration of the lower magnetic pole piece in an open type, the central position of a magnetic field distribution moves from the lens center to the sample side. Namely, the main surface of the lens can be brought closer to the sample side in such a way as from position (2) defined by a conventional static lens to position (1).</p> |
