Application of the INCL+ABLA reaction model to the study of the evolution of spallation targets

The design of spallation targets of accelerator-driven systems requires the use of reliable spallation reaction models embedded inside general transport codes. Nuclear reactions above ∼150 MeV are often reasonably well described by a Monte Carlo implementation of an intranuclear cascade (INC) model followed by a de-excitation model. The Li e intranuclear cascade model (INCL4) coupled to the ABLA evaporation-fission model has been shown to give a fairly good description of a large amount of experimental measurements for proton-induced spallation reactions on thin targets in the 200 MeV-2 GeV range, without free parameters. This model was recently improved in order to extend its capabilities and to cure some remaining shortcomings. These modifications bear on nuclear mean field, some aspects of pion dynamics, light charged clusters emission and low-energy extensions. In this paper we will compare both the modified and the standard versions of the INCL model with respect to their ability to reproduce thin target experimental measurements. After, we will tentatively validate the improved INCL model for particle emission and for residue production in thick targets. In order to estimate the residue production, MCNPX has been updated and coupled to the ORIGEN evolution code, through the use of the ALEPH system developed at SCK.CEN. The constraints on the reaction models brought by the thick target data, especially concerning radiotoxicity, will be compared with those provided by the similar comparison with thin target data. (authors)