A simplified model of radiation attenuation and energy absorption coefficients of the elements

This paper presents a model to predict mass attenuation and mass energy absorption coefficients of the elements for photons of energy from 1 keV to 20 MeV. The Compton scattering component is modeled by the attenuation and energy absorption of hydrogen at photon energies above 10 keV. Photoelectric attenuation and absorption is modeled as a simple power law of photon energy, modified by a simple function of the difference between the photon energy and the K shell binding energy of the absorber atoms. Attenuation and absorption by pair production above 1.022 MeV is modeled as a quadratic function of the square root of the photon energy. The mass attenuation and mass energy absorption coefficients of compounds can be predicted by the mixture rule. The errors in the model are greatest at the lowest photon energies, in part due to a lack of experimental data for photon energies below 1 keV. Worked examples are presented for the attenuation of photons at various energies in several elements and also in water over the whole range of photon energies.