The role of multifragmentation in spallation reactions is the subject of a long-standing discussion. It is generally agreed that highly-excited nuclear matter is spinodally unstable and that it should spontaneously break up into several fragments and unbound nucleons. However, it is not clear yet whether and to what extent a multifragmentation model is actually necessary for a reliable quantitative description of spallation reactions around 1 GeV. Not all nuclear de-excitation models include a multifragmentation stage; pure binary-decay models (coupled with a suitable intranuclear-cascade stage) have actually proved able to accurately reproduce several observables, such as double-differential nucleon spectra or residue yields. Hence, characteristic signatures of multifragmentation must be sought among other, more discriminating observables; the impact of a multifragmentation stage in de-excitation can then be assessed by comparing calculation results with experimental data.
We shall use the tools of hybrid cascade/de-excitation models to estimate the sensitivity of several physical observables to the de-excitation mechanism and assess the need for a multifragmentation model in the description of spallation reactions. Different state-of-the-art de-excitation models (ABLA07, GEMINI++, SMM) will be instrumental in identifying multifragmentation signatures. We shall focus our attention on discriminating observables such as correlations between charged particles and fragment velocity distributions.