$\gamma$ rays have been detected from 230-MeV negative pions incident on a water target. De-excitation $\gamma$ rays from ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{15}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, and ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$ have been identified and cross sections for excitation of particular residual states determined. Where necessary, the cross sections have been corrected for $\gamma$ feeding from higher states. Decays from short lived nuclear states result in Doppler broadened peaks which yield nuclear recoil momenta.

NUCLEAR REACTIONS ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}({\pi }^{-},\gamma X)$, $E=230\mathrm{}$ MeV, measured relative $\gamma$ yields at $\theta =90\mathrm{}°$.

• Received 8 April 1974

DOI:https://doi.org/10.1103/PhysRevC.10.1753