Comparison of Calculated Radiochemical Cross Sections with Experimental Results for Incident Protons andπ−Mesons in the 50- to 400-MeV Region: Effect of Varying a Few Nuclear Parameters in the Calculations

Abstract

Comparisons are made between theoretical predictions and experimental data for several ($p, \mathrm{xpyn}$) reactions involving C, Al, Cu, and U and for the (${\pi }^{-}, {\pi }^{-}n$) reaction in carbon. Interaction energies range from about 50 to 400 MeV. The theoretical model employs the two-step cascade-evaporation mechanism and includes the effect of the diffuse nuclear surface. The comparisons for the proton-initiated reactions indicate that agreement to within about 40% can be expected when the reaction cross section is about 100 mb, but the values can differ by factors of 5 or more when the cross section is about 10 mb. The agreement for the (${\pi }^{-}, {\pi }^{-}n$) reaction on carbon was fair. This reaction can be used for the measurement of the real part of the optical-model potential, and the method for doing so is described. The effects of the diffuse nuclear surface in conjunction with changes in the nuclear radius on the ($p, \mathrm{pn}$) reaction are discussed. Finally, results are given for the dependence of the ($p, \mathrm{xpyn}$) cross sections on the transition energy used in the calculation between the cascade and evaporation processes.