Ion source apparatus
US4641031A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 9, 1985 |
| Grant date | Feb 3, 1987 |
| Priority date | — |
| Expiry date | Jan 9, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J27/14
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An ion source apparatus comprising a bulk type thermionic cathode, which, when heated, emits thermoelectrons; an anode for causing a gas discharge in cooperation with the cathode thereby producing plasma; a grid electrode for extracting ions out of the plasma; a magnetic member for confining the plasma within a prescribed region; and a ferromagnetic body which surrounds the thermionic cathode. The ferromagnetic body removes the lines of magnetic force produced by magnets from the neighborhood of the surface of the thermionic cathode. As a result, thermoelectrons are freely emitted from the thermionic cathode, thereby ensuring a stable gas discharge.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.