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In this regime, the combined effects of field-enhanced thermionic and field emission can be modeled by the Murphy-Good equation for thermo-field (T-F) emission. [35] At even higher fields, FN tunneling becomes the dominant electron emission mechanism, and the emitter operates in the so-called "cold field electron emission (CFE)" regime.
Notably, the effect can be either heating or cooling of the surface emitting the electrons, depending upon the energy at which they are supplied. [4] Above the Nottingham inversion temperature, the emission energy exceeds the Fermi energy of the electron supply and the emitted electron carries more energy away from the surface than is returned by the supply of a replacement electron, and the ...
In this regime, the combined effects of field-enhanced thermionic and field emission can be modeled by the Murphy–Good equation for thermo-field (T-F) emission. [3] At even higher fields, FN tunneling becomes the dominant electron emission mechanism, and the emitter operates in the so-called "cold field electron emission (CFE)" regime.
From a thermodynamic viewpoint, [1] it is the use of electron vapor as the working fluid in a power-producing cycle. A thermionic converter consists of a hot emitter electrode from which electrons are vaporized by thermionic emission and a colder collector electrode into which they are condensed after conduction through the inter-electrode plasma.
There are other electron emission regimes (such as "thermal electron emission" and "Schottky emission") that require significant external heating of the emitter. There are also emission regimes where the internal electrons are not in thermodynamic equilibrium and the emission current is, partly or completely, determined by the supply of ...
The photoelectric work function is the minimum photon energy required to liberate an electron from a substance, in the photoelectric effect. If the photon's energy is greater than the substance's work function, photoelectric emission occurs and the electron is liberated from the surface. Similar to the thermionic case described above, the ...
Accelerating voltages can be between 3 and 40 kV. When the accelerating voltage is 20–25 kV and the beam current is a few amperes, 85% of the electron's kinetic energy can be converted into thermal energy. Some of the incident electron energy is lost through the production of X-rays and secondary electron emission.
The four emission mechanisms are thermal bremsstrahlung (braking) emission, gyromagnetic emission, plasma emission, and electron-cyclotron maser emission. The first two are incoherent mechanisms, which means that they are the summation of radiation generated independently by many individual particles. These mechanisms are primarily responsible ...