  The total production cross sections of light charged particles (LCPs),
intermediate mass fragments (IMFs) and heavy reaction products of p+Ni
collisions available in the literature have been compared with predictions of a
two-step model in the proton beam energy range from reaction threshold up to
approximately 3 GeV. Model cross sections were calculated assuming, that the
reaction proceeds via an intranuclear cascade of nucleon-nucleon collisions
followed by evaporation of particles from an equilibrated, heavy target
residuum. The shape of the excitation functions was well described by model
calculations for all reaction products. The magnitude of the cross sections was
reasonably well reproduced for heavy reaction products, i.e. for nuclei heavier
than Al, but the cross sections for lighter products were systematically
underestimated. This fact was used as an argument in favor of a significant
break-up contribution to the reaction mechanism. The present conclusions are
supported by recently published results of investigations of differential cross
sections in p+Ni collisions, which showed that hypothesis of the break-up of
target nucleus is indispensable for a good reproduction of d2 sigma/dOmega dE
for LCPs and IMFs.
