Chapter 5 - Radiation and Materials

Abstract

This chapter reviews some of the reactions that are important in the nuclear energy field. A variety of situations must be considered while putting the radiation and materials together. Bombarding particles may have low or high energy; they may be charged, uncharged, or photons; and they may be heavy or light in the scale of masses. The targets may be similarly distinguished, but they may also exhibit degrees of binding that range from none, as for “free” particles, to weak, as for atoms in molecules and electrons in atoms, to strong, as for nucleons in nuclei. In most interactions, the higher the projectile energy in comparison with the energy of binding of the structure, the greater is the effect. Radiation of special interest includes electrons, heavy charged particles, photons, and neutrons. Each of the particles tends to lose energy by interaction with the electrons and nuclei of matter, and each creates ionization in different degrees. The ranges of beta particles and alpha particles are short, but gamma rays penetrate in accordance with an exponential law. Gamma rays can also produce electron–positron pairs. Neutrons of both high and low energy can create radiation damage in molecular materials.