Systematics of spallation yields with a four-parameter formula

A semi-empirical four-parameter formula is proposed in order to systematize intermediate- and high-energy proton-induced spallation yields of target nuclei covering the 50-100 mass number interval. It is shown that the measured yields are reproduced by the formula with a degree of accuracy which is comparable with or better than those obtained in previous proton-spallation systemactics by other authors. The formula predicts reliable values for the most probable mass number of isotopic distributions. In addition, it allows one to derive in a simple way the mean nominal number of nucleons lost by the struck target nucleus, the charge- and mass-yield distributions for the spallation residuals, the total spallation reaction cross section, and the N/Z charge-dispersion curves. (orig.)