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The interactions of alpha particles with nuclei

The principal types of interactions of alpha particles with nuclei up to an energy of 200 MeV are reviewed, together with the theories used to understand their mechanisms. Elastic scattering is described by the optical model and this may be extended to include inelastic scattering by means of the coupled-channels formalism. The alpha particle may break up as it encounters the nuclear field and the fragments may or may not be captured by the nucleus. It is also possible for pick-up and stripping reactions to occur, as well as fragmentation. If the alpha particle, or one or more of its fragments, is captured by the nucleus it initiates a cascade of interactions leading to an equilibrated system that subsequently decays by statistical evaporation. During the course of this cascade pre-equilibrium particles can be emitted. Theories of these processes are described and these enable a quantitative understanding of the reactions to be attained.