Elastic scattering of 32S+32S, 40Ca+40Ca and 32S+4048Ca

Elastic scattering angular distributions and excitation functions have been measured for 32S+32S, 40Ca+40Ca and 32S+4048Ca at incident energies near the Coulomb barrier. The optical model analysis reveals a particular sensitivity to potential parameters for the cases of scattering between identical ions. This is attributed to the phase sensitivity in the coherent superposition of scattering amplitudes from complementary angles. In all systems investigated the depth of the absorptive potential at the nuclear surface is found to be nearly an order of magnitude smaller than the one deduced in recent measurements of 40Ca+40Ca. (Auth.)