INCL
general features

Basic assumptions of the model

INCL is a Monte-Carlo event generator for nuclear reactions induced by nucleons, pions or light ions.

The reaction are described as follows: the high-energy projectile(s) initiate an avalanche of binary collisions within the target nucleus. Particles (nucleons and pions) are individually followed and are assumed to move in a spherical calculation volume. Binary particle-particle collisions are subject to Pauli blocking. Emission of nucleons, pions and light clusters is possible; light clusters, in particular, are produced via a dynamical phase-space coalescence algorithm. The cascade stops when the remnant nucleus shows signs of thermalisation; a rather unique aspect of INCL is that the cascade stopping time is self-consistently determined.

The INCL model is not to be considered as adjustable. It does contain parameters, but they are either taken from known phenomenology (such as the matter density radius of the nuclei) or have been adjusted once for all (such as the parameters of the Pauli blocking or those that determine the coalescence module for the production of the light charged clusters).

The model cannot take into account coherent phenomena (elastic scattering, coherent excitation of low-lying levels, ...); on the other hand, it can predict reaction cross sections, partial cross sections for any reaction channel, particle correlations, etc. The energy range and other limits of the model are described here.

Coupling to statistical de-excitation codes

At the end of the intranuclear-cascade stage, the nucleus has yet to evacuate some of its excitation energy. This excited nucleus, called the cascade remnant, usually relaxes by particle emission (photons, nucleons, light nuclei), fission or other mechanisms (e.g. multifragmentation). The description of the de-excitation phase is however outside the scope of the intranuclear cascade and is usually treated by a separate statistical de-excitation code. It is important to understand that, in general, physical observables can be calculated only if the de-excitation of the cascade remnant is taken into account. There are exceptions (such as all the observables that concern pions) but the general rule is that de-excitation is always necessary.

The stand-alone INCL codes are distributed with couplings to a few de-excitation models. Do not hesitate to contact us if you need more information.