Filament for X-ray cathode
US9472371B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 2014 |
| Grant date | Oct 18, 2016 |
| Priority date | — |
| Expiry date | Dec 3, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2235/06
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Embodiments include an X-ray cathode filament, filament system, process to manufacture the filament and process to use the filament, where the filament includes a planar substrate, such as of tungsten, having a top surface coated with a coating of carburized tungsten (e.g., W2C) and thoria (ThO2). A first electron beam is emitted from the coating through a thermionic effect at a first temperature, such as when the filament is heated to between 1700 and 1900 degrees Celsius by running an electrical current through the filament. At this temperature, a second electron beam may be caused by (1) a reaction that includes creating thorium (Th) in the coating, and (2) the thorium diffusing to uncoated surfaces of the substrate from which the second electron beam is emitted. The filament may also have slots forming a zipper shape, forming a square switchback shape, or forming a rectangular labyrinth shape to reduce the current required to heat the filament.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.