Ca40(γ,p0)39K reaction forEγ=100-300 MeV

The differential cross section for the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(γ,${\mathrm{p}}_0$ ${)\mathrm{}}^{39}$K process has been measured in the energy range $E_{\gamma }$=100–300 MeV at laboratory angles of 45°, 90°, and 135°. The cross section for the (γ,p) reaction leaving ${}_{}{}^{39}{}_{}{}^{}\mathrm{K}$ in its ground state was extracted from the tip region of the proton spectra measured at a series of bremsstrahlung endpoint energies. The data are compared with a distorted-wave impulse-approximation calculation based on a direct, single-particle knockout mechanism.