Monte Carlo Calculations on Intranuclear Cascades. I. Low-Energy Studies

Abstract

Nuclear cascade calculations of the Goldberger type have been performed using the MANIAC electronic computer. A three-dimensional relativistic treatment was used. The target nuclei were ${\mathrm{Al}}^{27}$, ${\mathrm{Cu}}^{64}$, ${\mathrm{Ru}}^{100}$, ${\mathrm{Ce}}^{140}$, ${\mathrm{Bi}}^{209}$, and ${\mathrm{U}}^{238}$. Incident protons and neutrons with energies between 82 and 365 Mev have been studied, but meson production was neglected in this energy range. Cascades initiated by about 1000 incident particles were followed in each case.The results have been compared with those of previous calculations of this type, as well as with experimental photographic-plate data and counter measurements reflecting the cascade stage of high-energy nuclear reactions. The agreement with experimental data is usually good.Tables and graphs are presented showing the frequency of occurrence of various residual nuclei, and data on the residual nuclear excitation energy after the cascade is over. A few comparisons with radio-chemical data indicate over-all agreement with the general spallation pattern of copper with 340-Mev protons and good agreement with the ${\mathrm{Ni}}^{64}(p, n){\mathrm{Cu}}^{64}$ reaction over the energy range 100-400 Mev. However, the calculated results for the ${\mathrm{Cu}}^{65}(p, pn){\mathrm{Cu}}^{64}$ reaction are low by almost a factor of two, although the energy dependence is approximately correct.