Cross sections for photoproduction and electroproduction of ${\pi }^{+}$ on ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ and ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$ leading to bound states in the daughter nuclei have been measured at Kharkov in the energy range 600-1200 MeV by use of the activation method. Careful comparison is made to other recent results obtained at intermediate and high energies. Agreement is found between the present data and results of earlier work carried out at Lund and DESY. Discrepancies between photoproduction data taken at different laboratories are attributed to differences between methods of background subtraction. Relative bremsstrahlung-induced to electron-induced yield ratios are compared with predictions based on the Dalitz-Yennie formalism for virtual-photon spectra.

NUCLEAR REACTIONS ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}(\gamma ,{\pi }^{+})$, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}(e,e^{\prime }{\pi }^{+})$, ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}(\gamma ,{\pi }^{+})$, ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}(e,e^{\prime }{\pi }^{+})$. Activation method. $E_0=600\mathrm{}-1200$ MeV; measured ${\sigma }_q$ and ${\sigma }_e$, deduced ${\sigma }_k$; calculated $\frac{{\sigma }_q}{{\sigma }_e}$. Ge(Li) detector.

• Received 31 May 1977

DOI:https://doi.org/10.1103/PhysRevC.16.1513