What type of emission occurs in the cathode to produce electrons?

Thermionic emission is the process by which electrons are emitted from the surface of a heated cathode. In radiographic equipment, the cathode is heated to high temperatures, typically by an electric current flowing through a filament. This heating causes the cathode material, usually tungsten, to gain sufficient energy, allowing electrons to overcome the work function of the material and be released into the vacuum of the tube.

This phenomenon is crucial in the functioning of x-ray tubes, as it provides the necessary electrons that can be accelerated toward the anode to produce x-rays. Understanding thermionic emission is essential for grasping how cathodes operate in various applications involving electron flow and x-ray generation. Other forms of emission, such as photoelectric emission or quantum emission, do not pertain to the mechanism of electron production in the cathode.