Elastic Scattering of Nucleons and Heavy Ions

Abstract

At low collision energies, the Coulomb potential between two nuclei plays an important role. The attractive nuclear forces (which begin to act when the distance between the two surfaces is around 1–2 fm) and the repulsive Coulomb field provide the total interaction and give rise to a Coulomb barrier of height VB at a distance RB > Rcont = R1 + R2 (see Fig. 3.1a). At energies below that height (exemplified by E1 in Fig. 3.1), the colliding nuclei do not make close contact. The nuclear forces then play little role, and the only reaction channels observed are elastic scattering in the Coulomb field V (r) = Z1Z2e2∕r along with a small probability of inelastic excitations of the target and projectile nuclei (see below).