| 摘要 |
PURPOSE:To stably generate an ion beam by directly heating an emitter tip and also directly heating the ionization material to be melted around the emitter tip. CONSTITUTION:An ion source is formed with a crucible 2 containing an ionization material 1, an emitter tip 3 inserted into the crucible 2, a heater wire 4' heating the ionization material, and an extracting electrode 5, and the heater wire 4' is directly wound around the emitter tip 3. The ionization material can be heated by a direct resistor heating method using the emitter tip and heater wire or by a high-frequency induction heating method using the heater wire, and the beam current can be freely adjusted by adjusting the current flowing through the heater wire. The heater wire and emitter tip are in direct contact with the ionization material, thereby they are made of a material not reacted with the ionization material chemically and having a high melting point and low conductivity such as tungsten, for example. |
