| 摘要 |
PURPOSE:To obtain an ion source that can safely be operated for a long period by arranging a semi-sealed crucible with electric insulation around emitter chip containing a heater for heating a resistor or the emitter chip with a tooth-type edge and incorporating an ion source material therein. CONSTITUTION:An ion source consists of a filament 1 for heating a chip, emitter chip 2, control electrode 3, ion extraction electrode 4, ion source material 5, and such and an insulated crucible 9 is mounted around the chip 2 including the filament 1 and then the material 5 is incorporated in the crucible 9. By heating the filament 1, the material 5 is melted and the material 5 is supplied to the tip of the chip 2 in the melting state. Then ion extraction voltage is applied between the chip 2 and the electrode 4, and an ion beam 6 is extracted by electric field emission. Exhaust is performed by providing a small hole in the crucible 9 and a support stand 8 supports the filament 1. As a result, the stable ion can be extracted safely and for a long time from a harmful ion source material and the ion source material with high vapor pressure. |
