What is the primary function of the cathode in x-ray tubes?

The primary function of the cathode in x-ray tubes is to produce x-rays by generating a stream of electrons. The cathode consists of a thermionic filament that, when heated, emits electrons due to thermionic emission. These electrons are then accelerated towards the anode, where they interact with the target material, resulting in the production of x-rays.

The role of the cathode is critical, as it sets up the necessary conditions for x-ray generation through the creation and focusing of the electron beam. Once the electrons strike the anode, their sudden deceleration and interaction with the anode material produce x-ray radiation. Understanding this function is essential for grasping how x-ray machines operate and the underlying physics involved in radiography.