Compton scattering
Compton scattering is one of three competing processes when photons interact with matter. At energies of a few eV to a few keV, corresponding to visible light through soft X-rays, a photon can be completely absorbed and its energy can eject an electron from its host atom, a process known as the photoelectric effect. High energy photons of and above may bombard the nucleus and cause an electron and a positron to be formed, a process called pair production. Compton scattering is the most important interaction in the intervening energy region.