$\gamma$-ray spectra were recorded following bombardment of ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ targets by 220 MeV ${\pi }^{-}$ and 190 MeV ${\pi }^{+}$ beams. Residual nuclei were identified by their characteristic $\gamma$ rays and cross sections for production of specific states of daughter nuclei were calculated. Results for $\Delta A>\mathrm{}2\mathrm{}$ were found to be largely independent of the target and the charge state of the incident $\pi$. The resulting cross sections showed effects of binding energy and were in fair agreement with the results of an intranuclear cascade/evaporation calculation.

NUCLEAR REACTIONS ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}({\pi }^{\pm }, X\gamma )$, ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}({\pi }^{\pm }, X\gamma )$; $E_{{\pi }^{-}}=220\mathrm{}$ MeV; $E_{{\pi }^{+}}=190\mathrm{}$ MeV; detected $\gamma$ rays; Ge(Li); measured 90° $\sigma$ for multinucleon removal.

• Received 10 May 1978

DOI:https://doi.org/10.1103/PhysRevC.18.1368