  Spectra of outgoing neutrons and protons from the 6Li+55Mn reaction and
protons from the a+57Fe reaction have been measured with beams of 15 MeV 6Li
ions and 30 MeV alpha-particles. These reactions proceed through the same 61Ni
nucleus at the same excitation energy, thus allowing the difference in reaction
mechanism to be studied. It is shown that spectra from the first reaction
measured at backward angles are due to emission from a traditional compound
nucleus reaction, in which the intermediate nucleus has reached statistical
equilibrium; the spectra from the second reaction contain a significant
fraction of pre-equilibrium emission at all angles. Level density pa- rameters
of the residual nucleus 60Co have been obtained from the first reaction. Both
emission spectra and angular distributions have been measured for the second
reaction. It was found that the pre-equilibrium component exhibits a
forward-peaked angular distribution, as expected, but with a steeper slope than
predicted and with an unusual slight rise at angles above 120\deg. The
backward- angle rise is explained qualitatively by the dominance of the
multi-step compound mechanism at backward angles.
