Electromagnetic Radiations are classified into two one is Ionizing radiation (x-ray photon, gamma photon, particle radiation etc.) and another one is Non-ionizing radiation (radio waves, microwaves etc.). Out of these two Ionizing radiations are more harmful to environment, human beings and other living creatures in the world.
The attenuation of photon beam by an absorbing material caused by five major interactions such as Photodisintegration (P.D), Rayleigh scattering (R.C), Photoelectric Effect (P.E), Compton Effect (C.E), and Pair Production (P.P). The total attenuation coefficients are,
Total attenuation coefficient = P.D+P.E+C.E+P.P+R.C
1. The Physics of Radiation Therapy 4th Edition by F.M.Khan