摘要 |
A reservoir, extracting electrode and circular tungsten filament are maintained at high positive D.C. potential relative to a grounded electrode. Thermal electrons emanated from the filament irradiates and heats the bottom of the reservoir. As a result, powdered CsI held in the reservoir is melted and then forms a liquid CsI cone-shaped portion below the capillary formed at the reservoir bottom. Vaporized CsI molecules are created by further heating the cone-shaped portion, and are ionized by electron beam irradiation, so that a Cs+ ion beam is obtained.
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