Field free, directly heated lanthanum boride cathode
US4994706A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 2, 1987 |
| Grant date | Feb 19, 1991 |
| Priority date | — |
| Expiry date | Feb 2, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J1/15
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A directly heated cylindrical lanthanum boride cathode assembly is disclosed which minimizes generation of magnetic fields which would interfere with electron emission from the cathode. The cathode assembly comprises a lanthanum boride cylinder in electrical contact at one end with a central support shaft which functions as one electrode to carry current to the lanthanum boride cylinder and in electrical contact, at its opposite end with a second electrode which is coaxially position around the central support shaft so that magnetic fields generated by heater current flowing in one direction through the central support shaft are cancelled by an opposite magnetic field generated by current flowing through the lanthanum boride cylinder and the coaxial electrode in a direction opposite to the current flow in the central shaft.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.