The excitation functions for the pion-induced reactions $^{27}\mathrm{Al}$(${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$,xN${)}^{18}$F, $^{27}\mathrm{Al}$(${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$,xN${)}^{24}$Na, Si(${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$,xN${)}^{18}$F, and Si(${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$,xN${)}^{24}$Na have been determined for 50- to 390-MeV ${\ensuremath{\pi}}^{+}$ and 50- to 500-MeV ${\ensuremath{\pi}}^{\mathrm{\ensuremath{-}}}$. These excitation functions will enable experimenters to monitor high-intensity pion beams by activation of readily available high-purity Al foils or Si disks. The four excitation functions for $^{18}\mathrm{F}$ production and the two for $^{24}\mathrm{Na}$ production by ${\ensuremath{\pi}}^{+}$ show similar (3,3) resonance patterns. However, those for $^{24}\mathrm{Na}$ production by ${\ensuremath{\pi}}^{\mathrm{\ensuremath{-}}}$ are strikingly different in that the cross sections remain large from the resonance energy on down. This feature is attributed to increasing contributions from ${\ensuremath{\pi}}^{\mathrm{\ensuremath{-}}}$ absorption and charge exchange with decreasing energy.

The excitation functions for the $^{12}\mathrm{C}$(${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$,$\ensuremath{\pi}N$)$^{11}\mathrm{C}$ reactions have been established for 40- to 600-MeV ${\ensuremath{\pi}}^{\ensuremath{-}}$ and 50- to 520-MeV ${\ensuremath{\pi}}^{+}$. These excitation functions are dominated by the (3,3) pion-nucleon resonance but show an upward energy shift in the resonance peak for ${\ensuremath{\pi}}^{\ensuremath{-}}$ (to about 190 MeV) and a downward shift for ${\ensuremath{\pi}}^{+}$ (to about 160 MeV). The $\frac{\ensuremath{\sigma}({\ensuremath{\pi}}^{\ensuremath{-}})}{\ensuremath{\sigma}({\ensuremath{\pi}}^{+})}$ ratio at 180 MeV is 1.59\ifmmode\pm\else\textpm\fi{}0.07. The results are compared with theoretical calculations based on a semiclassical transport model including nucleon charge exchange and an intranuclear cascade model.NUCLEAR REACTIONS $^{12}\mathrm{C}$(${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$,$\ensuremath{\pi}N$)$^{11}\mathrm{C}$, excitation functions, $E{\ensuremath{\pi}}^{+}=50\ensuremath{-}520$ MeV, $E{\ensuremath{\pi}}^{\ensuremath{-}}=40\ensuremath{-}600$ MeV. Plastic scintillator targets, measured $^{11}\mathrm{C}$ by ${\ensuremath{\beta}}^{+}\ensuremath{-}\ensuremath{\gamma}$ coincidences. Compared with semiclassical transport and intranuclear cascade calculations.

The excitation function for the formation of 24Na in the interaction of gold with protons has been determined between 200 and 800 MeV and the 24Na cross section measured for 294 MeV π+.

The excitation functions for the reactions $^{12}\mathrm{C}({\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}, \ensuremath{\pi}N)^{11}\mathrm{C}$ have been measured by activation over the energy ranges 50 to 470 MeV for ${\ensuremath{\pi}}^{+}$ and 40 to 550 MeV for ${\ensuremath{\pi}}^{\ensuremath{-}}$. These excitation functions, clearly reflecting the (3,3) pion-nucleon resonance, show an upward energy shift in the resonance peak for ${\ensuremath{\pi}}^{\ensuremath{-}}$ and a downward shift for ${\ensuremath{\pi}}^{+}$. The $\frac{{\ensuremath{\sigma}}_{{\ensuremath{\pi}}^{\ensuremath{-}}}}{{\ensuremath{\sigma}}_{{\ensuremath{\pi}}^{+}}}$ ratio at 180 MeV is 1.55 \ifmmode\pm\else\textpm\fi{} 0.10.

The excitation functions for the reactions $^{12}\mathrm{C}({\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}, \ensuremath{\pi}N)^{11}\mathrm{C}$ have been measured by activation over the energy ranges 50 to 470 MeV for ${\ensuremath{\pi}}^{+}$ and 40 to 550 MeV for ${\ensuremath{\pi}}^{\ensuremath{-}}$. These excitation functions, clearly reflecting the (3,3) pion-nucleon resonance, show an upward energy shift in the resonance peak for ${\ensuremath{\pi}}^{\ensuremath{-}}$ and a downward shift for ${\ensuremath{\pi}}^{+}$. The $\frac{{\ensuremath{\sigma}}_{{\ensuremath{\pi}}^{\ensuremath{-}}}}{{\ensuremath{\sigma}}_{{\ensuremath{\pi}}^{+}}}$ ratio at 180 MeV is 1.55 \ifmmode\pm\else\textpm\fi{} 0.10.