Abstract
The28Si+64Ni reaction at 163.8 MeV incident energy is studied by measuring in coincidenceγ-rays and charged particles identified from Z=2 to Z=16. The transition from quasi-elastic to more damped reactions is observed when the difference between the detected charge and the projectile one is increased. The strong influence of the particle decay on the measuredγ-ray multiplicity is evidenced with the help of the statistical model computer code CASCADE. Dissipative events are well described in the rolling limit with excitation energy equally shared between the fragments. The overall agreement is lost for the fragments with the projectile charge which show a small value of theγ-multiplicity even for dissipative events. This is probably connected with the previously observed non statistical behavior of gamma rays emitted in coincidence with projectile-like fragments. In the alpha-spectrum measured in coincidence with gamma-rays, the deexcitation of fused systems is clearly separated from in flight emission of deep inelastic fragments. The low measured gamma-ray multiplicity for fusion events is qualitatively explained taking into account the effect of alpha-emission in the statistical decay.
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We would like to acknowledge Dr. J.P.S. Van Schagen for helpful discussions on the results of this paper. Dr. R. Novotny for suggestions on BaF2 and photomultiplier bases assembly. The contribution of the whole technical staff of the electronic service of the LNS was indispensable for the BaF2 mounting. Continuous assistance of the MEDEA group has been largely appreciated. We thank also Mr. V. Campagna and E. Costa for the help in mounting the experimental apparatus and the Tandem technical staff for the high quality beam.
A particular thank is due to the referee for some enlightening suggestions.
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Di Pietro, A., Cardella, G., Musumarra, A. et al. Gamma-ray multiplicity measurements in the28Si+64Ni reaction at 163.8 MeV. Z. Physik A - Hadrons and Nuclei 350, 199–205 (1994). https://doi.org/10.1007/BF01289583
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DOI: https://doi.org/10.1007/BF01289583