Ion source
US4687938A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 1985 |
| Grant date | Aug 18, 1987 |
| Priority date | — |
| Expiry date | Dec 12, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/08
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An ion source includes an ion source material holder adapted to load an ion source material thereon and having an aperture at the bottom thereof, an ion emitter mounted on the ion source material holder at the aperture, heating means for heating the ion source material holder and the ion emitter, and an ion extracting electrode for extracting an ion beam from the ion emitter. The ion emitter is made of a mixture of a material having a large work function and a material having a small work function, in order to be able to emit both positive ions and negative ions from the ion emitter. The polarity of a voltage applied between the ion emitter and the ion extracting electrode is changed so that one of the positive ion beam and the negative ion beam can be selectively extracted from the ion emitter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.