Large area directly heated lanthanum hexaboride cathode structure having predetermined emission profile
US4795940A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1987 |
| Grant date | Jan 3, 1989 |
| Priority date | — |
| Expiry date | Oct 14, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J1/16
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A large area directly heated lanthanum hexaboride (LaB.sub.6) cathode system (10) is disclosed. The system comprises a LaB.sub.6 cathode element (11) generally circular in shape about a central axis. The cathode element (11) has a head (21) with an upper substantially planar emission surface (23), and a lower downwardly and an intermediate body portion (26) which diminishes in cross-section from the head (21) towards the base (22) of the cathode element (11). A central rod (14) is connected to the base (22) of the cathode element (11) and extends along the central axis. Plural upstanding spring fingers (37) are urged against an outer peripheral contact surface (24) of the head end (21) to provide a mechanical and electrical connection to the cathode element (11).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.