Stepped indirectly heated cathode with improved shielding
US11244800B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 2021 |
| Grant date | Feb 8, 2022 |
| Priority date | — |
| Expiry date | May 26, 2041 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/082
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An ion source for forming a plasma has a cathode with a cavity and a cathode surface defining a cathode step. A filament is disposed within the cavity, and a cathode shield has a cathode shield surface at least partially encircling the cathode surface. A cathode gap is defined between the cathode surface and the cathode shield surface, where the cathode gap defines a tortured path for limiting travel of the plasma through the gap. The cathode surface can have a stepped cylindrical surface defined by a first cathode diameter and a second cathode diameter, where the first cathode diameter and second cathode diameter differ from one another to define the cathode step. The stepped cylindrical surface can be an exterior surface or an interior surface. The first and second cathode diameters can be concentric or axially offset.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.