Transition from complete to incomplete fusion in asymmetric heavy ion reactions

Heavy residues from very mass-asymmetric heavy-ion reactions

“…This effect was seen in the isotopic yields for isotopes with low Z values. Previous measurements of the elemental cross sections from similar systems are plotted as pluses [36][37][38]. Note that the cross sections measured in the present work cover a range of elements not measured in the complex fragment studies.…”

“…Information about this source was extracted from coincidence measurements of the complex fragments. The observed source velocity (vsource) was shown to be consistent with complete fusion at low beam energies (E/ A< 30 MeV /nucleon) [17,38) and with incomplete fusion at higher beam energies (E/ A> 30 MeV /nucleon) [26,36). The center-of-mass angular distributions (du/dO) of the complex fragments were isotropic for a range of fragments with masses between the mass of the projectile and that of the target.…”

“…Previous studies of complex fragment emission have presented distributions of Ztotal versus Vsource [21,29,38,36]. The source velocity, Vsource, is defined as (11) where mi and Vi are the mass and velocity, respectively, of the i-th detected complex fragment.…”

“…For asymmetric heavy ion reactions at intermediate bombarding energies, the elemental cross sections for fragments with masses between those of the projectile and the light particles have been accounted for by a complete or incomplete fusion process followed by statistical de-excitation [38,26]. Although a systematic study of the cross sections has been carried out for fragments with masses between those of the light particles and the projectile .…”

“…By gating on the Vsource, it was possible to characterize the mass and excitation energy of the compound nuclei formed in these incomplete fusion processes. This work was extended to higher bombarding energies for the 129 Xe + Ti and Cu reactions at 26 and 31 MeV /nucleon [38]. An incomplete fusion model calculation which incorporated statistical emission from the hot products reproduced the following experimental data: the elemental cross sections, the emission velocities of the decay products, the center-of-mass angular distributions, and the source velocity distributions.…”