Relative yields of 36 products extending from ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ to ${}_{}{}^{65}{}_{}{}^{}\mathrm{Zn}$ have been measured for the interaction of 500-and 1570-MeV negative pions with Cu. These results are compared with calculations from the ISOBAR model, with earlier studies of Cu spallation with lower (resonance) energy pions, energetic protons, and heavy ions. Relative yield patterns at both ${\pi }^{-}$ energies show only slight differences when compared to spallation by protons of comparable energy. Calculations from the ISOBAR model adequately reproduce the shapes of the mass yield and charge yield of the experimental data for 500-MeV ${\pi }^{-}$. The calculation, however, overestimates the yield of neutron-rich isotopes from deep spallation. At the 1570-MeV ${\pi }^{-}$ energy the yield patterns, charge-dispersion, and mass-yield curves are nearly identical to those for 2-GeV proton spallation. These results suggest that pion-nucleon resonance effects probably decrease at higher energies and that limiting fragmentation and factorization concepts may be applied to understanding high-energy pion spallation.

NUCLEAR REACTIONS $\mathrm{Cu}({\pi }^{-}, \mathrm{spallation})$, $E_{{\pi }^{-}}=500\mathrm{} \mathrm{and} 1570$ MeV, measured relative $\sigma (A, Z)$, products ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$-${}_{}{}^{65}{}_{}{}^{}\mathrm{Zn}$. Deduced charge-dispersion and mass-yield curves. Comparison with intranuclear cascade and evaporation calculations. Natural targets, Ge(Li) detectors, radiochemistry.

• Received 7 August 1978

DOI:https://doi.org/10.1103/PhysRevC.18.2241