Determination of emission parameters from field emission sources
US8779376B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 10, 2012 |
| Grant date | Jul 15, 2014 |
| Priority date | — |
| Expiry date | Nov 8, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/065
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The state of an emitter can be determined by measurements of how the current changes with the extraction voltage. A field factor β function is determined by series of relatively simple measurements of charged particles emitted at different conditions. The field factor can then be used to determine derived characteristics of the emission that, in the prior art, were difficult to determine without removing the source from the focusing column and mounting it in a specialized apparatus. The relations are determined by the source configuration and have been found to be independent of the emitter shape, and so emission character can be determined as the emitter shape changes over time, without having to determine the emitter shape and without having to redefine the relation between the field factor and the series of relatively simple measurements, and the relationships between the field factor and other emission parameters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.