Heavy-ion induced transfer reactions with spherical and deformed nuclei

Cross sections for the quasielastic channels have been measured at energies slightly above the Coulomb barrier using 58Ni and 112,116Sn projectiles on targets of 117,118Sn and 161,162,163,164Dy. The deexcitation γ-rays were detected in a 4π NaI array (the Spin Spectrometer of Oak Ridge National Laboratory) in kinematic coincidence with both target-like and projectile-like particles; thus providing a measure of the total energy and multiplicity of the entry state. The reaction channels were identified by characteristic γ-deexcitation transitions measured with Ge detectors substituted for array elements in the Spin Spectrometer. The angular distribution for inelastic scattering is well described by both semiclassical and quantal calculations. Two general features for few-neutron transfer channels are observed; (i) the dependence of the total cross section on the ground-state Q-value, (ii) the 'coldness' of the reaction mechanism indicated by the measured entry states. For one-neutron transfer the distorted-wave Born approximation seems to give a correct overall qualitative description of the reaction mechanism for spherical nuclei, and reproduces the cross sections within a factor of two. The ground-to-ground two-neutron transfer probability for the reaction between Sn isotopes was deduced and found to be strongly enhanced (F ≅ 760), which is consistent with the expectation of strong pairing correlations. (orig./HSI)