A new version of the Liège intranuclear cascade ͑INC͒ model is proposed for the description of spallation reactions. Compared to the previous version, it incorporates new features: ͑i͒ it can accommodate a diffuse nuclear surface, ͑ii͒ the treatment of the Pauli blocking effect is improved, removing unphysical features linked with the use of statistical blocking factors, ͑iii͒ collisions between moving spectator nucleons are explicitly suppressed, ͑iv͒ pion dynamics is improved, especially concerning the delta lifetime, ͑v͒ it can accommodate light ions as incoming projecticles, ͑vi͒ the remnant angular momentum is included in the output of the model. Another important feature is the self-consistent determination of the stopping time, i.e., the time at which the INC calculation is terminated and coupled to evaporation. The predictions of the model, used with the Schmidt evaporation code, are tested against a large body of experimental data, in the 200-MeV-2-GeV range for incident energy per nucleon, including total reaction cross sections, neutron, proton, pion, and composite double differential cross sections, particle multiplicities, residue mass and charge distributions, and residue recoil velocity distributions. Good agreement is generally obtained without additional varying parameters. It is shown that the introduction of a diffuse surface considerably improves the description of the total reaction cross sections, of the intensity of the quasielastic peak in proton and neutron double differential cross sections and of the residue production yield for isotopes close to the target. High energy neutron spectra are found to be sensitive to details of the deuteron structure in deuteron-induced reactions. The shape of the fragmentation peaks in residue mass spectra is shown to be closely related to the shape of the distribution of the excitation energy left after the cascade stage. The longitudinal residue recoil velocity and its fluctuations display typical random-walk characterics, which are interpreted as a direct consequence of the independence of successive binary collisions occurring during the cascade process and therefore provide a strong support of the basic hypotheses of the INC model. Small but systematic discrepancies between model predictions and experiment are identified and possible further improvements to reduce them are discussed. The influence of the evaporation model is investigated. A comparison with similar approaches is presented.

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.