Thermionic-enhanced field emission electron source composed of transition metal carbide material with sharp emitter end-form
US10083812B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 22, 2016 |
| Grant date | Sep 25, 2018 |
| Priority date | — |
| Expiry date | Jan 10, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2209/0223
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electron source emitter is made from transition metal carbide materials, including hafnium carbide (HfC), zirconium carbide (ZrC), titanium carbide (TiC), vanadium carbide (VC), niobium carbide (NbC), and tantalum carbide (TaC), which are of high refractory nature. Preferential evaporating and subsequent development of different crystallographic planes of the transition metal carbide emitter having initially at its apex a small radius (50 nm-300 nm) develop over time an on-axis, sharp end-form or tip that is uniformly accentuated circumferentially to an extreme angular form and persists over time. An emitter manufactured to the (110) crystallographic plane and operating at high electron beam current and high temperature for about 20 hours to 40 hours results in the (110) plane, while initially not a high emission crystallographic orientation, developing into a very high field emission orientation because of the geometrical change. This geometrical change allows for a very high electric field and hence high on-axis electron emission.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.