Two-neutron transfer in the 6He + 120Sn reaction

A large yield of a particles produced in the Sn-120(He-6, alpha) reaction was measured at 20.3-, 22.2-, 22.4-, and 24.5-MeV bombarding energies. The alpha particles are distributed over a broad energy range in the vicinity and below the elastic scattering He-6 peak. Energy integrated alpha-particle cross sections have been obtained at theta(lab) = 36 degrees, 40 degrees, and 60 degrees. The alpha energy distributions have been analyzed at a fixed laboratory angle (approximate to 60 degrees) in terms of , the reaction Q value, considering the 2n-transfer reaction kinematics Sn-120(He-6, alpha)Sn-122. A kinematical analysis of the Q-value distribution shows that the recoil system Sn-120 + 2n is formed in highly excited states in the continuum, at increasing excitation energies as the bombarding energy increases. It is shown that by using Brink's formula, the excitation energy depends on the transferred angular momentum following a linear relation with the square of the angular momentum, indicating that some kind of dinuclear rotating system is formed after the reaction.