| 摘要 |
PROBLEM TO BE SOLVED: To efficiently obtain the most suitable brightness to save labor of an operator, by adjusting the deflection system of an electron gun after the replacement of a filament, setting a saturated point, fully automating a function to derive a desired emission current, and using that function. SOLUTION: A camera mechanism is provided in an observation room, the horizontal component of the deflection system of an electron gun is adjusted by calculating the position of a beam, and the oblique component of the deflection system of the electron gun is adjusted so that the maximum quantity of a current can be obtained, by detecting the amount of a beam current. After that, the condition of the beam is calculated by calculating the size of the beam, and a filament voltage and a bias voltage are automatically adjusted so that an emission current set at a saturated point can be obtained, by detecting the amount of the current.
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