| 摘要 |
PURPOSE:To enable enhancement of the exhaustion speed of an ion pump by distributing the kinetic energy of ion, which are incident upon cathodes, within an area of a large sputtering ratio by controlling the electric potential of a discharge space by means of a dischrge controlling electrode which extends from one of the cathodes to the hollow space of an anode. CONSTITUTION:An electron group is developed in the hollow space 2 of an anode 1 by the magnetic field of a magnet 13 and a cross electromagnetic field, which developes due to the difference between the electric potentials of the anode 1 and cathodes 3. Most of ions which are produced from gaseous molecules due to above electron group, bump against the cathodes 3 without bumping against a discharge controlling electrode 15, and sputters a cathode-covering matter which consists of a getter member. The anode 1 is earthed, the electrode 15 is given an electric potential, and the cathode 3 is given an electric potential lower than that of the electrode 15. Besides, the electric potential of a discharge space formed in the hollow space 2 of the anode 1 is controlled by the electrode 15. Therefore, the exhaustion speed of the ion pump can be increased by increasing the sputtered amount of the getter member. In addition, by using collecting electrodes 4, a stable exhaustion speed can be realized even for a rare gas. |
