| 摘要 |
An ion source of the side extraction type which includes auxiliary electrodes surrounding the cathode at the ends of the anode, and insulators surrounding the auxiliary electrodes and electrically isolating them from the anode. The auxiliary electrodes essentially define the ends of the discharge chamber, leaving the anode confined to the cylindrical surface surrounding the filament. Each insulator is made up of an inner insulator and an outer insulator with an annular space defined between them. The inner and outer insulators are each in the form of a cylinder with a radially extending flange formed at one end, and interfit with the anode and with each other such that cylindrical spaces are defined between the outer flange portion and the anode and between the inner and outer flange portions. These and other features contribute to improve the electrical isolation between the auxiliary electrode and the anode, prolong source life, and improve beam purity.
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