Quasi-elastic processes in−58andinduced64reactions on Sn isotopes

Quasi-elastic reactions were studied for ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ beams at 330 MeV and ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$ beams at 341 and 380 MeV incident energy, respectively, on even-A Sn isotopes. Angular distributions were measured in the range 20°≤${\theta }_{\mathrm{lab}\mathrm{\le }55}$° using a magnetic spectrograph with a gas-filled focal-plane detector yielding single mass and charge resolution; generally individual states were not resolved. Cross sections for quasi-elastic one-neutron pickup and stripping reactions vary smoothly with the ground-state Q value. Total quasi-elastic transfer cross sections range from 340 to 640 mb, corresponding to 20–40 % of the total reaction cross section determined from the elastic scattering angular distributions. The distribution of the total cross section into the various reaction channels is discussed.