| 摘要 |
PURPOSE:To secure such an ion pump as capable of increasing the amount of a cathode material to be spattered and consequently increasing the exhaust rate, by providing a negative electric potential, which has suchlike potential difference as the larger clearance the large disparity, for a spatter electrode, in accordance with clearance between both electrodes' cathode through parts to the cathode. CONSTITUTION:Gaseous molecules which are ionized by an electron group made up at a hollow part 2 of an anode 1 entirely collide with a spatter electrode 15 practically and getter matter on its surface is spattered. The spatter electrode 15 exists atop the axis center of the hollow part 2 of the anode 1 and passes through it so that in the axial direction, a state of uniform electric discharge is kept intact except in the vicinity of the cathode surface. Since the anode 1, a cathode 3 and the spatter electrode 15 are all arranged in axial symmetry to the electric discharge part, uniform electric discharge is maintained even in the azimuthal direction around the symmetry axis. Therefore, to steadily operate this invented ion pump, it is necessary to secure an adequate potential distribution and for this reason, only when the potential distribution is given to each electrode, stable electric discharge can be realized. |
