| 摘要 |
PURPOSE:To decrease heating electric power required for producing ion from an ionized matter having a relatively high melting point, and shorten preparation time required until a stable beam is obtained by installing the main part of a pin-like anode on an ionized-matter supporting part made of a heat-resistant insulating member and arranging around the ionized matter, a filament, by the electronic impact of which the ionized matter is heated and molten. CONSTITUTION:A pin-like anode 1 is formed by the use of a glassy carbon bar with a diameter of about 0.8mm., and has a pointed end having a radius of curvature below 10mum. An ionized-matter supporting part 2 is made of insulating alumina, and has a U- form boat-like shape. The bottom of the supporting part 2 is provided with a hole which has a diameter of about 1.5mm. and through which the pin-like anode 1 penetrates in such a manner that its end protrudes from the bottom surface of the supporting part 2 by 0.5-1.5mm.. A coil-like filament 4 is provided around the ionized matter 3, so that electrons discharged from the filament 4 directly impact upon the ionized matter 3 and the pin-like anode 1 to heat them. The pin-like anode 1 protrudes from the center hole of a shield electrode 5 by 0.5-1mm.. A lead-out electrode 6 is installed facing the pin-like anode 1, and an ion beam 7 is discharged at a lead-out voltage of 10-15kv. |
