Excitation functions for complex fragment emission in the E/A =20--100 MeV 14N+natAg, 197Au reactions

Excitation functions have been measured for complex fragments with atomic number Z=3--15 emitted in collisions of E/A=20--100 MeV 14N ions with targets of natAg and 197Au. The results are analyzed in terms of a three-source model which includes: projectilelike fragments from peripheral processes, nonequilibrium emission, and statistical decay of fully equilibrated compound nuclei. Nonequilibrium emission of complex fragments is found to increase rapidly relative to equilibrium emission up to E/A∼60 MeV and then remain approximately constant thereafter. Evidence for enhanced production of heavier intermediate-mass fragments is found in the data for reactions with the natAg target at energies above E/A∼60 MeV. Fit parameters for the equilibrium and nonequilibrium sources are examined. In particular, it is observed that the temperature parameter for nonequilibrium emission of complex fragments is independent of bombarding energy up to E/A=100 MeV