Systematics of complex fragment emission in niobium-induced reactions

Emission of intermediate mass fragments from hot116Ba* formed in low-energy58Ni +58Ni reaction

“…It will be interesting to apply similar considerations to 116 Ba * when similar data on TKEs become available. Also, it would be of interest if the statistical fission model, as introduced in the GEMINI code [1] could also be applied to the 58 Ni+ 58 Ni reaction and its predictions compared with the present cluster decay model results as well as to the pure Hauser-Feshbach BUSCO results. Furthermore, a similar comparison using the alternate picture as generalized liquid-drop model [12] or the so-called unified fission models for cluster decay studies [9] is called for since these models do not introduce any preformation factor.…”

“…At higher energies, the lighter α-like fragment 8 Be competes with it, though we know that 8 Be is unbound in the ground state. Note that the charge number Z changes with T for some fragments (here for the mass 17 fragment) and hence at higher T's the measurements of charge distributions become equally important [1,16]. The sudden increase in the production cross section (λ-value) for 17 F at T≥3.2 MeV is due to its enhanced penetrability P, the Q-value effect.…”

“…complex fragments with masses lighter than A<20, are emitted from both the light (A∼60) and medium-mass (A∼110) compound systems, and may arise as multiple "clusters", and are accompanied by multiple light particles (Z≤2) production. This light-particle emission, associated with evaporation residues production, is very satisfactorily understood as the fusion-evaporation process from an equiliberated compound nucleus in the statistical Hauser-Feshbach formalism [1,2,3,4,5], described in evaporation codes such as LILITA and CASCADE or many other codes. The Hauser-Feshbach formalism has been extended to include the above noted observed complex IMFs, for example in the BUSCO code [2] or in the Extended Hauser-Feshbach Method based on the scission-point picture [5].…”

“…An alternative process for the IMFs production is the binary decay of a compound nucleus in the statistical fission model of Moretto [6] or of Vandenbosch and Huizenga [7]. The fission model of [6] is used in the GEMINI code [1] for the heavier compound systems (A>100), whereas the saddle-point transition-state model based on fission model of [7] is used for the lighter systems (A<80) [4]. The emission of light particles (n, p, α or γ-ray) in both of these fission models is still calculated within the Hauser-Feshbach formalism [8].…”

Coincidence Measurement of Residues and Light Particles in the ReactionFe56+pat 1 GeV per Nucleon with the Spallation Reactions Setup SPALADIN

“…This can be ascribed to the fact that ABLA is a "classical" de-excitation model in which only the evaporation of neutrons, protons and alpha particles is possible. To account for the emission of IMF, several de-excitation mechanisms can be envisaged: A generalized evaporation, as modeled in GEM [8] which evaporates particles up to Mg; a binary splitting as described in GEMINI [9], which uses the Moretto-type transition state model [10] for the emission of intermediate mass fragments down to a certain limit, the evaporation of lighter fragments being treated within the HauserFeshbach formalism; the opening of multifragmentation channels, as included in SMM [11]. Default parameters of the models have been used except for GEMINI for which the transition from the Hauser-Feshbach to the Transition State Model is made for Z≥4 as recommended by the author [12].…”