X-ray attenuation

the decrease in the number of photons in an X-ray beam due to interactions with the atoms of a material substance. Attenuation is due primarily to two processes, absorption and scattering. In both processes, the X-ray photon interacts with the atoms of the material. In scattering, the X-ray photon continues with a change in direction with or without a loss in energy. In absorption, the energy of the X-ray photon is completely transferred to the atoms of the material. In coherent or elastic scattering, the X-ray is scattered with no energy transferred to the material. In Compton scattering, some of the X-ray energy is used to eject an electron from an atom, and the X-ray is scattered with a reduced energy. In photoelectric absorption, all of the X-ray photon energy is used to eject one of the inner shell electrons from an atom. In all of these interactions, the X-ray photon is removed from the primary X-ray beam, and the process contributes to the beam attenuation. See also scattered radiation (I), Fig. 1.

DLP