Pre-equilibrium emission and its possible relation toα-clustering in nuclei

Abstract

The study of nuclear states built on clusters bound by valence neutrons in their molecular configurations is a field of large interest. Clustering becomes particularly important at the dripline, where weakly bound systems prevail. For light nuclei, at an excitation energy close to the particle separation value, there are experimental evidences of such structure effects, but this is still not the case for heavier nuclear systems. Several theoretical efforts have been done in the development of pre-formation alpha-clustering models, but there is still a lack of experimental data capable to give a direct feedback. The search of alpha-cluster evidences in medium-mass systems is therefore a new challenge which can give new hints in this field of research.

Investigation of nuclear reaction mechanisms of Nickel isotopes at various energies induced by alpha particles

“…This computer code system is used for the analysis and prediction of nuclear reactions and helped researchers to determine both the compound and pre-compound excitation functions [20]. In computer code COMPLET, the particles in the initial configuration (n o =Ex 1 +Ex 2 +Ex 3 ) can be neutron, proton or alpha particle represented by the exciton numbers Ex 1 , Ex 2 and Ex 3 respectively [19,21,22].…”

“…In pre-equilibrium emission calculations, the initial excitation configurations and level density parameters are very essential quantities [7]. The nuclear level density influences the shape and the height of the calculated excitation functions [21,23]. The expression for nuclear reaction cross-section may be written from the consideration of decay rate equation governing nuclear transformation and decay of the activated products [23].…”

“…The reaction cross-sections of the investigated reactions compared with the data given in the on-line EXFOR library [24][25][26]. This library is based on both default and adjusted computer code COMPLET calculations [2,21,25]. To achieve a better description of available data for (α, n+p) reactions in these codes, a phenomenological energy dependent enhancement factor was introduced based on cross sections for medium and heavy nuclei.…”