Generating electrons with an activated photocathode
US7015467B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 2003 |
| Grant date | Mar 21, 2006 |
| Priority date | — |
| Expiry date | May 26, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/31779
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electron beam apparatus comprises a beam source to generate a radiation beam that is directed onto a photocathode to generate an electron beam. The photocathode comprises an electron-emitting material composed of activated alkali halide, such as for example, cesium bromide or cesium iodide. The activated alkali halide has a lower minimum electron emission energy level than the same material in the un-activated state, and provides efficient photoyields when exposed to radiation having an energy level that is higher than the minimum electron emission energy level. The emitted electrons can be collimated into beams and used to write on, inspect, or irradiate a workpiece.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.