COMPLEX FRAGMENT EMISSION IN THE 200-MEV HE-4-NAT, AU-197 REACTIONS(AG)

Spectra, angular distributions, and cross sections have been measured for Z=3-14 fragments produced in 200-MeV He-4-induced reactions on Ag- nat and Au-197 targets. In addition, isotopic yields were measured at forward angles. Two-component moving-source fits have been performed o n the data to evaluate the relative contributions of nonequilibrium an d equilibrium emission mechanisms. At forward angles, the complex frag ment yields are dominated by nonequilibrium emission, with IMF energie s extending from the emission barrier to momenta in excess of the inci dent beam. Backward of 90 degrees the yields are nearly isotropic and exhibit spectra consistent with emission from an equilibrated composit e nucleus.