Transfer and breakup processes in reactions of 11- and 17-MeV/nucleon 20Ne

Abstract

The mechanisms of transfer and breakup in heavy-ion-induced reactions have been studied for the $^{20}$Ne${+\mathrm{}}^{197}$Au system at bombarding energies of 220 and 341 MeV. A 4\ensuremath{\pi} detector was used to separate reactions leading to the production of projectilelike fragments into components having either two charged bodies in the final state (transfer) or three or more charged fragments (breakup). For both components, angular distributions, energy spectra, and production cross sections are shown for projectile fragments of Z=3--9. The ratio of transfer to inclusive yields initially drops steeply with decreasing ejectile charge, leveling off for Z\ensuremath{\le}7. The lower bounds on this ratio are \ensuremath{\simeq}60% and \ensuremath{\simeq}30% at 220 and 341 MeV, respectively. At 341 MeV, the trends in the central moments (mean, width, and skewness) of the ejectile energy spectra, as a function of Z, are similar for transfer and breakup. The primary ejectile yields are deduced from the breakup and transfer cross sections, and comparisons are made with the predictions of various models. The relatively large probabilities for primary ejectiles to be produced in charged-particle-bound states, observed for all Z and at both 220 and 341 MeV, indicate that, on average, most of the excitation energy resides in the heavy, targetlike fragment.