What is the primary function of the cathode in radiography?

The primary function of the cathode in radiography is to produce a thermionic cloud. The cathode is composed of a filament that heats up when an electric current passes through it. This heating causes the release of electrons through a process known as thermionic emission, forming a cloud of electrons around the filament. These electrons are then accelerated toward the anode, where they interact with the target material to produce x-rays.

Producing a thermionic cloud is crucial because it is the source of electrons needed for x-ray production. Without this cloud, the generation of x-rays would be impossible, as there would be no electrons to collide with the anode and create the necessary radiation.