ORIGIN OF CORRELATIONS BETWEEN EVAPORATION PROTONS AND DISCRETE GAMMA-RAYS IN HEAVY-ION FUSION-EVAPORATION REACTIONS

We have investigated correlations between evaporated protons and discr ete gamma rays in the heavy-ion fusion-evaporation reactions Ni-58(Al- 27,3p)Sr-82 and Ni-58(Si-28,4p)Sr-82. 3p-gamma and 4p-gamma coincidenc es were measured using a 4pi charged-particle detector array. The even ts studied were completely reconstructed kinematically in order to det ermine the excitation energy of formation of Sr-82. Correlations arisi ng from well-understood kinematic effects were measured and found to b e well reproduced by predictions made by the statistical-model evapora tion code PACE2. Dynamical correlations due to nuclear structure effec ts were searched for by measuring proton spectra in coincidence with d iscrete gamma rays from four rotational bands in Sr-82. Contrary to pu blished results, no significant shifts of the first moment of the spec tra were observed.