Nuclear shapes and the imaginary part of the light ion nuclear optical potential

The imaginary part of the light ion optical potential has some interesting features which may be usefully exploited. For the 3He-nucleus system at medium energies it has been found that the elastic scattering cross-sections in the backward hemisphere are almost entirely determined by the imaginary part of the optical potential. The dynamics of this potential corresponds to energy conserving transitions in which (i) the 3He excites the target collective states and (ii) the 3He itself undergoes incoherent lp lh excitations using as intermediate states the single particle levels of the target nucleus. It has been found that the back angle elastic scattering data is very sensitive to the nature of the target collective states that enter into the calculation of the imaginary potential. Thus we have an additional way of studying nuclear shapes. (orig.)