Vacuum Electron Sources. Recent Technical Trend of Thermionic Cathodes.

Solid-State and Vacuum Thermionic Energy Conversion

A brief overview of the research activities at the Thermionic Energy Conversion (TEC) Center is given. The goal is to achieve direct thermal to electric energy conversion with >20% efficiency and >1W/cm power density at a hot side temperature of 300-650C. Thermionic emission in both vacuum and solid-state devices is investigated. In the case of solid-state devices, hot electron filtering using ...

Low Emittance Thermionic Electron Guns*

Recent Advances in Polarized Electron Sources*

Current experimental physics programs at a number of electron accelerator laboratories worldwide require the delivery of high average current highly polarized electron beams for long periods of time. The polarized electrons are produced by near bandgap photoemission from certain semiconductor photocathodes. We observe the quantum efficiency of these cathodes to be inversely related to the total...

Thermionic electron emission microscopy of metal-oxide multilayers on tungsten

Introduction Thermionic cathodes are used in many industrial vacuum electronic applications. Vacuum tubes for high-frequency or high-power applications are one example (e.g., see [1]). The emission properties of thermionic electron sources in vacuum devices are often Bimproved[ by the addition of oxide coatings on the metal cathode surface [2, 3]. The explanation of the improvement is usually b...

In-FEEP Thruster Ion Beam Neutralization with Thermionic and Field Emission Cathodes

Charge neutralization of an In-FEEP thruster was demonstrated with three different electron sources by zeroing the floating potential of the thruster and neutralizer system. The three cathodes used in the investigation include a mixed metal thermionic cathode, a carbon nanotube field emission cathode, and a Spindt-type Mo field emission array cathode. The field emission cathodes significantly i...