| 摘要 |
PROBLEM TO BE SOLVED: To improve processing and assembling accuracy concerning aberration irrespectively of a conductor sample and an insulator sample, and ensure electric insulation and heat dissipation. SOLUTION: A perimeter side partial section 15b of a yoke 15 is composed by dividing in two sections of an upper yoke 15b1 near a sample 7, and lower yoke 15b2 far from the sample 7, and a gap 18 is formed between those opposite end edges. A coil 17 which generates magnetism is equipped in the lower yoke 15b2, and the upper yoke 15b1 consists of a material which can generate an electric field and magnetic field, such as iron. When a conductor sample 7 is observed, both the yokes 15b1, 15b2 are set as earth electric potential, and when an insulator sample 7 is observed, the upper yoke 15b1 is floated on negative high voltage, and the lower yoke 15b2 is set as earth voltage. Thereby, an objective lens 10 is enabled to perform an acceleration action and a convergence action of electron emitted form the sample 7, irrespective of the kinds of samples.
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