Deeply inelastic transfer reactions induced by heavy ions in rare-earth targets

Abstract

Recoil techniques have been used for a systematic study of deeply inelastic transfer reactions induced in rare earth targets by40Ar,52Cr,56Fe and63Cu projectiles. The targets were separated isotopes of Eu, Sm, Nd and Pr. The residual nuclei149gTb,150Dy and151Dy were identified by their radioactive properties. The reactions studied involved the transfer of 3 to 7 charges from projectile to target. The c.m. angular and energy distributions were measured over the whole angular range from 0 to 180° (c.m.). A special device was used to measure accurately the c.m. energy of products emitted in the angular range 170–180° in the c.m.s. The c.m. angular distributions depend strongly on the ratio of the incident energy to the strong interaction barrier, and slightly on the number of transferred charges. The c.m. energy distributions are typical of completely damped collisions for 6-charge transfer reactions, and include a contribution of partially damped collisions for 4-charge transfer reactions. A kinematic analysis was used to determine the most probable number of neutrons transferred in the first reaction step with a given number of protons. The numbers found correspond to equilibration of the neutron to proton ratio in the composite system.