Thermionic emission
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Thermionic emission is the liberation of charged particles from a hot electrode whose thermal energy gives some particles enough kinetic energy to escape the material's surface. The particles, sometim
Closeup of the filament in a low pressure mercury gas-discharge lamp showing white thermionic emission mix coating on the central portion of the coil. Typically made of a mixture of barium, strontium and calcium oxides, the coating is sputtered away through normal use, eventually resulting in lamp failure.
One Edison effect bulb consisted of an evacuated bulb with an externally-wired electrode such as a metal plate in this example (variants used platinum foil or extra wire instead) isolated from the carbon filament (hairpin-shaped in this example).
Schottky-emitter electron source of an electron microscope
Electron gun
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An electron gun is an electrical component in some vacuum tubes that produces a narrow, collimated electron beam that has a precise kinetic energy.
Thermionic emission
…The thermionic emission law has been recently revised for 2D materials in various models. In electron emission devices, especially electron guns, the thermionic electron emitter will be biased negative relative to its surroundings. This creates an electric field of magnitude E at the emitter…
Electron gun from a cathode-ray tube
The electron gun from an RCA Vidicon video camera tube
Electron gun from an oscilloscope CRT
A photoinjector based on a "one and a half cells" microwave cavity at a frequency of 2856 MHz.