ABSTRACT
The chapter is concerned with the electromagnetic interaction between the incoming charged particles and the material they traverse. There are three kinds of interactions between charged particles and matter: the electromagnetic interaction, the "strong" interaction, and the "weak" interaction. The strong interaction is the one that gives rise to nuclear reactions, and to pion, and other particle production by the protons or the α particles. The weak interaction is some 10-12to 10-14 times weaker than the electromagnetic and the strong interactions. It is the interaction that causes β decays and electron capture. The chapter considers the types of γ-ray interactions with matter. They are the Rayleigh scattering, the photoelectric effect, the Compton scattering, the pair production, the photonuclear reactions, and the meson production. Due to the interactions with the medium material, the primary γ rays will degrade in their spectrum.
