Pion-induced spallation of copper across the (3,3) resonance

Cross sections for about two dozen radioactive spallation products have been measured for 50-, 100-, 190-, and 350-MeV ${\pi }^{\pm }$ and for 200- and 350-MeV proton interactions with copper. Sums of measured pion-induced cross sections at 50 and 350 MeV are about the same as for protons of 200 and 590 MeV, respectively. However, at 100 and 190 MeV, nearer to the (3,3) pion-nucleon resonance, these pion-induced cross section sums are 50 to 75% greater than those for protons of similar total energy. Ratios of the ${\pi }^{-}$ to ${\pi }^{+}$ cross sections are greater than unity for neutron-rich products and less than unity for neutron-deficient products at all four energies, indicating that pion absorption is a substantial reaction mode, even at 190 and 350 MeV. At 100 MeV, and especially at 50 MeV, absorption appears to dominate over inelastic scattering and the $\frac{{\sigma }_{\pi }^{-}}{{\sigma }_{\pi }^{+}}$ ratios are noticeably changed from those at the higher energies. The intranuclear cascade plus evaporation codes reproduce the proton cross sections fairly well. The pion version of the intranuclear cascade code reproduces the pion results quite well at 350 MeV, but it underestimates them significantly at 50 and 100 MeV.