| 摘要 |
PURPOSE:To obtain a fine ion source with high intensity capable of radiating the desired ion seed when heated and applied with an electric field by carbonizing a filament or a needle-like surface layer formed with a transition metal. CONSTITUTION:A transition metal and a compound made of Si only or two or more elements are alloyed to form a prototype of a filament or a sharp needle, and the prototype is carburized to carbonize its surface layer. For example, a filament bored with a diameter of 0.5mm. at its center by machining ribbon- like tantalum (with a width of 1.5mm., a thickness of 0.1mm., a length of 20mm.) is heated at 2,200 deg.C for 60sec for carburization by introducing several Torr of C2H4 in a vacuum furnace, then a likewise-carburized sharp needle 10 is inserted into the hole of the filament 11 to form an ion source comprised of a liquid metal reservoir 9. At this time, TaC is formed on the surface of the filament and sharp needle. |
