Thermionic emission occurs in metals that are heated to a very high temperature. In other words, thermionic emission occurs, when large amount of external energy in the form of heat is supplied to the free electrons in the metals.

Where does thermionic emission occur in xray tube?

In the generation of X-ray production, a cathode filament machined in a cathode cup is activated, causing intense heating of the cathode filament. The heating of the filament leads to the release of electrons in a process called thermionic emission.

How does thermionic emission occur?

Thermionic emission is the emission of electrons from a heated metal (cathode). ... As the temperature increases, the surface electrons gain energy. The energy acquired by the surface electrons allows them to move a short distance off the surface thus resulting in emission.