Classic X-ray tubes and the particle accelerator today offer us a choice of two processes for the artificial generation of X-rays. The most widely utilised are X-ray tubes, where X-rays are created by excessively accelerated electrons that emit electrons on impacting with an anode. The electrons emit element-specific energy in the form of X-rays when the gaps created are filled. As 99 % of the energy utilised to generate an X-ray occurs as lost heat, modern X-ray rotating anodes distribute the focal spot (burn mark) over the edge of the anode through rapid rotation (3000-9000 1/min).

These anodes today usually consist of graphite or ceramics, with the points at which the electrons impact being coated with the metals or alloys required to generate the desired wavelength. Anodes made of coated graphite or ceramics exhibit superior thermal capacity, thermal conductivity and deflection and a high degree of strength at high temperatures when compared to purely metal anodes made of tungsten or molybdenum. Moreover, as the density of graphite is only 10 % that of tungsten, the rotating mass of the anode is considerably less.