| 摘要 |
<p>PURPOSE:To make it possible to emit a low energy electron beam without reducing the velocity of the electron beam and at low field emission voltage, by keeping the distance between a cathode and an anode small using a specified work method. CONSTITUTION:It is possible to decrease a field emission voltage required for obtaining the density of a constant field emission current by shortening distance between a cathode 1 and an anode 9. A tungsten single crystal wire 6 is welded on the top position of a V-shaped welded tungsten filament 5, and fixed on an anode cylinder 10 through a support stem 7, insulation glass 8 and a pressure ring 11. A platinum disc 9 with a small hole in its center is placed at the aperture part of the anode cylinder 10. A minute distance is formed by electropolishing between plate 9 and cathode 1 after polishing wire 6, under such a condition that wire 6 is isolated from the edge of the hole of plate 9. Because of this distance, the electron beam with low energy can be emitted at a low voltage.</p> |
