  The energy and angular dependence of double differential cross sections
d2sigma/dOmega dE were measured for p, d, t, 3,4,6He, 6,7,8Li, 7,9,10Be,
10,11B, and C produced in collisions of 1.2, 1.9, and 2.5 GeV protons with a Ni
target. The shape of the spectra and angular distributions does almost not
change whereas the absolute value of the cross sections increases by a factor
about 1.7 for all ejectiles in this beam energy range. It was found that energy
and angular dependencies of the cross sections cannot be reproduced by the
microscopic model of intranuclear cascade with coalescence of nucleons and the
statistical model for evaporation of particles from excited, equilibrated
residual nuclei. The inclusion of nonequilibrium processes, described by a
phenomenological model of the emission from fast and hot moving sources,
resulting from break-up of the target nucleus by impinging proton, leads to
very good reproduction of data. Cross sections of these processes are quite
large, exhausting approximately half of the total production cross sections.
Due to good reproduction of energy and angular dependencies of d2sigma/dOmega
dE by model calculation it was possible to determine total production cross
sections for all studied ejectiles. Results obtained in this work point to the
analogous reaction mechanism for proton induced reactions on Ni target as that
observed previously for Au target in the same beam energy range.
