Principle: When fast moving electrons are suddenly stopped then X- rays are produced.
Production: 1. When the cathode is heated by electric current it produced electron due to thermionic emissions. 2. The beam of electron is then focused on the anode (target). 3. The electrons from cathode are accelerated by applying of high voltage between cathode & anode using step up transformer. 4. When these fast moving electrons are suddenly stopped by tungsten anode, they lose their kinetic energy and x rays are produced from the target. Some amount of Kinetic energy is Converted to large amount of heat. 5. By controlling the filament current, the thermionic emission of electron hence intensity of X- rays can be controlled. 6. The X-rays of high penetrating power and higher frequency are called hard X-rays and those with low frequency are called soft X-rays. 7. The intensity of X-ray depends on filament current, penetrating power of X-ray depends on P.D. between cathode and anode.