Reaction mechanisms and staggering in collisions

Within the dinuclear system model fusion-fission reactions 78 Kr+ 40 Ca and 86 Kr+ 48 Ca is investigated. The charge distributions of the decay products are predicted at bombarding energy 10 MeV/nucleon. The competition is treated between complete fusion followed by the decay of compound nucleus and quasifission channels. The possible explanation of the odd-even staggering in the yield of the final reaction products at high excitation energies is discussed.

“…As found in Ref. [11], the staggering depends in a more complicated way on the history of the evaporation chain than the schematic interpretation suggested in Ref. [10].…”

Section: Resultsmentioning

confidence: 64%

Description of the Fusion-Fission Reactions in the Framework of Dinuclear System Conception

Kalandarov

Adamian

Antonenko

et al. 2016

“…It seems that the neutron excess in the entrance channel affects the yields of the light fragments. An Influence can be originated also by structure effects [10] linked to the pairing forces, and it could be connected with the Symmetry Energy.…”

Section: Charge Distributionmentioning

confidence: 99%

Isospin influence on the decay modes of compound systems produced in the^78,86Kr +^40,48Ca at 10 AMeV

Pirrone

Politi

Wieleczko

et al. 2016

Self Cite

Abstract. The study of the decay modes competition of the compound systems produced in the collisions 78 Kr+ 40 Ca and 86 Kr+ 48 Ca at 10AMeV is presented. In particular, the N/Z entrance channel influence on the decay paths of the compound systems, directly connected to the isospin influence, is investigated. The experiment was performed at the INFN Laboratori Nazionali del Sud (LNS) in Catania by using the 4π multi-detector CHIMERA. Charge, mass, angular distributions and kinematical features of the reaction products were studied. The analysis shows some differences in the contribution arising from the various reaction mechanisms for the neutron poor and neutron rich systems. Comparison with theoretical statistical and dynamical models are presented for the two systems. Besides a study of the influence of the energy on the entrance channel is performed for the 78 Kr+ 40 Ca reaction, by comparing the results of this experiment to those obtained for the same system at 5.5 AMeV with the INDRA device at GANIL.

“…Odd-even effects in Z distributions were already observed in spallation [12], compound nucleus [13] reactions, but never in well-selected multifragmentation events. As visible in fig.…”

mentioning

confidence: 92%

“…By using the technique of ref [13], namely dividing the charge distributions by themselves after a five-points smoothing, the odd-even staggering becomes manifest. As in all other data, we observe a more pronounced staggering for the neutron-poor system.…”

mentioning

confidence: 99%

Isospin effects in central heavy-ion collisions at Fermi energy

Galichet

Rivet

Gagnon-Moisan

et al. 2012

N/Z effects were observed on variables measured in central Xe on Sn collisions around the Fermi energy. Comparisons were made with dynamical simulations of collisions in which the symmetry term of the EOS was varied. In this framework it appeared that the observed effects were due to the dynamics of the reaction and not to the deexcitation of the hot primary fragments.The elaboration of the Equation of State (EOS) for nuclear matter requires more experimental constraints, particularly for the formulation of an adequate symmetry term whose density dependence at sub-and supranormal density is still debated. Isospin dependent observables measured in reactions induced by judiciously chosen projectile-target couples already provide some hints on the symmetry term; the derived form is however highly model-dependent. Thus cross-checks making use of a large body of variables and models are necessary to obtain reliable information.