New potentialities of the Liège intranuclear cascade model for reactions induced by nucleons and light charged particles

Abstract

The new version (INCL4.6) of the Liège intranuclear cascade (INC) model for the description of spallation reactions is presented in detail. Compared to the standard version (INCL4.2), it incorporates several new features, the most important of which are: (i) the inclusion of cluster production through a dynamical phase space coalescence model, (ii) the Coulomb deflection for entering and outgoing charged particles, (iii) the improvement of the treatment of Pauli blocking and of soft collisions, (iv) the introduction of experimental threshold values for the emission of particles, (v) the improvement of pion dynamics, (vi) a detailed procedure for the treatment of light-cluster induced reactions taking care of the effects of binding energy of the nucleons inside the incident cluster and of the possible fusion reaction at low energy. Performances of the new model concerning nucleoninduced reactions are illustrated by a comparison with experimental data covering total reaction cross-sections, neutron, proton, pion and composite double differential cross-sections, neutron multiplicities, residue mass and charge distributions, and residue recoil velocity distributions. Whenever necessary, the INCL4.6 model is coupled to the ABLA07 de-excitation model and the respective merits of the two models are then tentatively disentangled. Good agreement is generally obtained in the 200 MeV-2 GeV range. Below 200 MeV and down to a few tens of MeV, the total reaction cross section is well reproduced and differential cross sections are reasonably well described. The model is also tested for light-ion induced reactions at low energy, below 100 MeV incident energy per nucleon. Beyond presenting the update of the INCL4.2 model, attention has been paid to applications of the new model to three topics for which some particular aspects are discussed for the first time. The first topic is the production of clusters heavier than alpha particle. It is shown that the energy spectra of these produced clusters are consistent with coalescence. The second topic regards the longitudinal residue recoil velocity and its fluctuations. Excellent results are obtained for these quantities. It addition, it is shown that the distributions of these quantities display typical random-walk characterics, at least for not too large mass losses. They are interpreted as a direct consequence of the independence of successive binary collisions occurring during the cascade process. The last topic concerns the total reaction cross section and the residue production cross sections for low energy incident light ions. It is shown that our new model can give a rather satisfactory account of these cross sections, offering so an alternative to fusion models and the advantage of a single model for the progressive change from fusion to pre-equilibrium mechanisms.

Evaporation-cost dependence in heavy-ion fragmentation

“…We use the INCL model, first developed at Liège by Cugnon and further developed at CEA-Saclay [23,24]. The latest version of the code can simulate reactions on light nuclei up to A = 18 [25].…”

Recent Developments of the Liège Intranuclear Cascade Model in View of its Use into High-energy Transport Codes

“…The model is now able to rather well predict heliuminduced total reaction cross sections [6]. It also reasonably reproduces the different reaction channels that open with increasing incident energy.…”

“…It is therefore necessary to ensure that they correctly predict at least the gross features of these interactions, although this falls well beyond the alleged theoretical limit of validity of INC models. This is why the treatment of low-energy composite particle induced reactions has been improved in [6].…”

“…A new version, INCL4.6, very similar to INCL4.5 for nucleon-induced reaction above 100 MeV but significantly improved for composite projectiles and energies below 100 MeV, has recently been released [6]. It is now implemented into PHITS [7] and in a version of MC-NPX [8], coupled respectively to the GEM and ABLA07 de-excitation models.…”

New experimental approaches to investigate the fission dynamics

“…In order to investigate the dynamics of the fission process up to the saddle point, we use state-of-the-art calculations performed with the intra-nuclear cascade code INCL [40] coupled to the deexcitation code ABLA07 [23]. In intra-nuclear cascade codes, the collision of a high-energy projectile within a target nucleus initiates a succession of binary nucleon-nucleon collisions that may lead to the emission of pre-equilibrium nucleons.…”