Abstract
We present data for the132Xe+56Fe-system at 5.73 MeV/u laboratory energy. Due to inverted kinematics, where Xe is the projectile, we were able to measure energy spectra as well as angular distributions for reaction products with 20≦Z≦60 with unitZ-resolution; i.e. target- and projectile-like fragments have been investigated. The reaction shows a well focussed quasielastic component, where charge transfer from the light to the heavy collision partner dominates. This apparent tendency towards more asymmetric fragmentation is explained by a potential energy surface which favours such charge transfer in order to minimize the asymmetry energy of the liquid drop. The strongly damped component which constitutes the major part of the reaction cross section exhibits characteristics of a fusion-fission reaction with typical fission fragment kinetic energies and 1/sinΘ c.m. angular distributions.
The maximum cross section is found for the symmetric fragmentation, no clear indication is observed for a diffusion process leading to target- and projectile-like fragments. Our data are difficult to reconcile either with the standard diffusion models or with an equilibrated compound nucleus fission picture. We tentatively conclude that an essential part of the fully damped cross section originates from partial waves for which the compound nucleus has no fission barrier.
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On leave from University of Marburg, Federal Republic of Germany
We would like to express our gratitude to the UNILAC staff for providing an excellent beam even in the early stage of operation and the data-aquisition-group for extensive support. We also acknowledge stimulating and clarifying discussions with H.C. Britt, W. Nörenberg and G. Wolschin. Two of us (B. H. and C.V.) want to thank Professor R. Bock and GSI for the kind hospitality during their stay at Darmstadt.
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Heusch, B., Volant, C., Freiesleben, H. et al. The reaction mechanism in the system132Xe+56Fe at 5.73 MeV/u: Evidence for a new type of strongly damped collisions. Z Physik A 288, 391–400 (1978). https://doi.org/10.1007/BF01417723
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DOI: https://doi.org/10.1007/BF01417723