Pre-aligned thermionic emission assembly
US8581481B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 25, 2011 |
| Grant date | Nov 12, 2013 |
| Priority date | — |
| Expiry date | Aug 4, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/06308
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A thermionic emission assembly includes a Wehnelt cap that has a cap beam aperture and a cavity within which a cathode is supported. Electrical energy applied to the cathode causes it to reach a sufficiently high temperature to emit a beam of electrons that propagate through the cap beam aperture. An anode having an anode beam aperture is positioned in spatial alignment with the cap beam aperture to receive the electrons. The anode accelerates the electrons and directs them through the anode beam aperture for incidence on a target specimen. A ceramic base forms a combined interface that electrically and thermally separates the Wehnelt cap and the anode. The interface thermally isolates the Wehnelt cap from the anode to allow the cathode to rapidly reach the sufficiently high temperature to emit the beam of electrons.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.