| 摘要 |
PROBLEM TO BE SOLVED: To provide a converged ion beam device equipped with a quick- response electrostatic lens system which enables automatic focusing. SOLUTION: The external electrode 12 on one side of an objective lens 3 is connected with a lens power supply 14, being insulated from a lens barrel. The lens power supply 14 may be of ordinary DC voltage power supply emitting an output voltage variable within the range +500 V. This type of power supply has a quick responsiveness as high as several tens of kHz. If the voltage applied by the power supply 14 on the external electrode 12 is changed, the focal distance of the objective lens 3 can be varied, despite on a minor scale. If around 500V is applied on the external electrode 12 when the energy of the ion beam is 30 keV, the focus of the beam varies about 100μm. Use of this objective lens 3 enables automatic focusing.
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