Spectra, angular distributions, and cross sections have been measured for Z=3–12 fragments produced in the reaction of 161-MeV protons with a silver target. Nonequilibrium mechanisms dominate the fragment yields at forward angles and for low-Z ejectiles. Equilibrated emission is primarily responsible for fragments observed at backward angles, an effect which grows in importance with increasing fragment Z value. A power-law fit to the elemental cross section distributions yields an exponent τ=4.7, significantly larger than observed for higher-energy protons. These data are compared with the predictions of statistical decay, accreting source, and preequilibrium calculations.

• Received 11 August 1989

DOI:https://doi.org/10.1103/PhysRevC.41.79