Target residues from the reaction of 2.6 GeV protons with gold and thorium nuclei have been studied with radiochemical techniques. Chemical separations were used to enhance the sensitivity for detecting target residues in the near-target region. These data are compared to a new empirical parametrization of the mass and charge yields of fragmentation, or spallation, products based on a comprehensive analysis of data in the literature. Data include results from both projectile and target fragmentation studies. The new near-target residues provide significant new insight into the variation of the cross sections of products near in mass to the target (or projectile). The results of this study and the empirical description are compared to the internuclear-cascade model of these reactions.

• Received 9 July 1990

DOI:https://doi.org/10.1103/PhysRevC.42.2546