Arthur Holly Compton discovered the scattering of x-ray photons when they collide with graphite atoms and demonstrated the relationship between the deflection ankle of the x-ray photon and its energy loss (Compton shift). He becomes in 1927 awarded with the Nobel prize for the 'Compton Effect' discovery.

See Compton Effect.

The attenuation of radiation is a decrease in intensity as a result of interactions by transmission through matter. X-ray beams attenuate due to photon absorption by the material or scattering. Both effects are energy dependent. The probability of absorption or scattering is a function of the photon energy. The photoelectric absorption is much more energy dependent than the Compton scatter effect.

See also Attenuation Correction, Linear Energy Transfer, Broad Beam and Ion Beam.