Isotopic yields of neutron-rich nuclei from deep-inelastic reactions

We follow up on our earlier work involving a light projectile (⁴⁸Ca) to populate high spin states in neutron-rich nuclei with results from experiments involving a heavier projectile (¹⁵⁴Sm) for the purposes of studying isotopic yields. These yields, which in some cases were measurable down to a level of 0.1% of the total reaction cross section, are presented from three separate reactions. A trend in the isotopic yields towards N/Z equilibration is observed in one experiment having a large disparity in N/Z ratios between the projectile and target. In the two other reactions, where the N/Z driving force is less pronounced, the yields are instead clustered around the projectile and target nuclei. We present correlated projectilelike and targetlike fragment isotopic yields derived from γ-γ coincidences, a technique that enables one to partition the yield of an isotope according to the amount of neutron evaporation. Using this method we find that for the zero-neutron evaporation channel transfer occurs predominantly into the light fragment, consistent with the nature of the deep-inelastic mechanism. We further find that multiple-neutron evaporation contributes substantially to the yields of the isotopes.