| 摘要 |
PURPOSE:To acquire a liquid metallic ion source with a long service life and a stable performance, by forming a pulse shape electric field over the surface of a molten ionizing substance, and removing thereby heat-unmeltable impurities floating over the surface of the molten ionizing substance around the tip of an emitter. CONSTITUTION:At the potential side of an emitter 1, is arranged a high voltage pulse power source 15 to enable to apply a pulse shape high voltage. While the ion source operates normally, the high voltage pulse power source 15 does not operate. However, when the heat-unmeltable impurities accumulate around the tip of the emitter 1, causing to disturb a stable ion emission, the power source 15 is activated to apply a pulse shape high voltage to the emitter 1, that is, to the molten ionizing substance 5. In such a way, heat-unmeltable impurities floating and accumulating at the tip of the emitter 1 can be removed.
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