The main parts/components of an X-ray generator are the tube, the voltage generator, the control console, and the cooling system. X-rays are produced in an evacuated tube made up of thin-walled glass material filled with the vacuum is needed. On one side of the tube, V-Shaped tungsten wire is positioned. This is literally called thermionic cathode. A cylinder with one side inclined face is located at the other end of the tube and this is considered as the anode. This anode is made up of refractory metal that conducts heat well.
A high voltage source is connected to the tube. The positive terminal of the voltage source is connected to the anode and the negative terminal of the voltage source is connected to the cathode. The thermionic cathode will get heated up by introducing electric current to it. This will initiate a thermal movement on the heated wire. The thermal movement forces some electrons to move from the wire surface. By initiating the high voltage supply a song electric field between the thermionic cathode and anode is generated. This strong electric field between them will force the electrons towards the anode, thus an electron beam is formed.
The accelerated beam will collide with the anode vigorously in high velocity. The anode will slow down the electrons in a short distance and this generates the desired X- Rays. Because of the inclination of anode surface, the intensity of X-Ray radiation is more on to the corresponding side but a certain part of the radiation will also propagate to other directions. The protective housing is provided to shield the unwanted directions of X-Ray Radiation. The desired X-Rays are only allowed to move outside through a small transparent window provided at one side of the housing.
To restrict the adequacy in X-rays generation due to a large area on the anode, an electromagnetic lens is used to focus the electron beam on a small spot of the anode surface. I.e. the smaller the focus spot, sharp and contrast the image will be.
X-ray generators are of several sizes and designs. There are stationary units that are proposed for use in lab, inspection, production, maintenance and compact portable systems that can be carried site by site. Generators are available in wide ranges. While inspecting steel or heavier metal parts, the equipment is capable of delivering a large range of electron volt might be important to enter the full thickness of the material. On the other hand, lightweight parts may just require a ten of kilovolts.