Pair transfer processes probed at deep sub barrier energies

Multinucleon transfer cross sections in the system Ca-40+Zr-96 have been measured at bombarding energies ranging from the Coulomb barrier to similar to 25% below. Target-like (lighter) recoils in inverse kinematics have been completely identified in A,Z and Q-value with the large solid angle magnetic spectrometer PRISMA. The experimental slopes of the neutron transfer probabilities at large internuclear separation are consistent with the values derived from the binding energies. A phenomenological interpretation of the transfer probabilities indicates the presence of enhanced values for the even number of neutron transfers.