Monte Carlo Calculations on Intranuclear Cascades. II. High-Energy Studies and Pion Processes

Abstract

The nuclear cascade calculations described in the preceding paper have been extended to incident energies up to 1.8 Bev with the inclusion of pion production, scattering, and absorption processes. Again the MANIAC electronic computer was used. Several incident proton energies between 450 Mev and 1.8 Bev have been investigated, with ${\mathrm{Al}}^{27}$, ${\mathrm{Cu}}^{64}$, ${\mathrm{Ru}}^{100}$, ${\mathrm{Ce}}^{140}$, ${\mathrm{Bi}}^{209}$, and ${\mathrm{U}}^{238}$ as target nuclei. Cascades initiated by pions of several energies up to 1500 Mev incident on ${\mathrm{Ru}}^{100}$ have also been studied. The elementary cross sections used and the assumptions made about details of the inelastic nucleon-nucleon and pion-nucleon processes are presented. The results of the calculation are summarized in tables and graphs giving data on transparencies, on numbers, energy spectra, and angular distributions of emitted cascade nucleons and pions, and on frequencies of occurrence and excitation energies of residual nuclei. The computed number distributions, energy spectra, and angular distributions of emitted particles are compared with the results of several emulsion experiments with incident protons and negative pions. The agreement is generally satisfactory, but certain discrepancies are found, for example regarding spectra and angular distributions of emitted pions; some of these discrepancies are discussed in terms of details of the model used. The calculation predicts quite well the over-all yield distribution of spallation products of copper produced by 2-Bev protons; however, as at lower energies, the calculated cross sections for ($p, \mathrm{pn}$) reactions are too low by factors of two or three.