Plasma-anode electron gun
US4707637A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 24, 1986 |
| Grant date | Nov 17, 1987 |
| Priority date | — |
| Expiry date | Mar 24, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J3/021
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A plasma-anode electron gun includes a cathode means of a material such as molybdenum having a relatively high ratio of emission of secondary electrons to impinging helium ions. A hollow annular anode structure (16) contains an ionized plasma, and has a central opening (38) through which the electron beam (36) is directed, when ions from the anode are released to impinge upon the cathode (12). The anode and ion source structure may be grounded, and ions are released through openings facing the cathode when a positive trigger pulse is applied to one or more electrodes extending within the plasma. The cathode is preferably operated at a voltage in the order of thirty to two hundred thousand volts negative with respect to the cathode. Leakage of ions from the hollow anode may be inhibited by the provision of a supplemental grid biased to a low positive potential.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.