ABSTRACT
This chapter discusses the beam of radiation is attenuated as it passes through matter applies equally to both neutrons and photons. The concept of the interaction coefficient is first introduced to describe how readily radiation particles interact with matter, and then use it to quantify the attenuation of a beam of neutral particles passing through some material. The interaction of a given type of neutral radiation with matter may be classified according to the type of interaction, the matter with which the interaction takes place. Scattered radiation is of great concern in interpreting the results of radiation detectors. Scattering transfers a spectrum of energies to the scattering medium as a result of the different scattering angles that can occur. Incoherent scattering refers to the interaction of a photon with an individual electron, as distinguished from the coherent interaction of a photon with all electrons of an atom.
