Photoproton Cross Section for ¹⁹F

Abstract

Proton energy spectra have been measured at 90° for the ¹⁹F(e, e′p)¹⁸O reaction in the giant resonance region. The (γ, p₀) and (γ, p₁) differential cross sections are extracted from the proton energy spectra by using virtual-photon spectra. The integrated differential cross section of the (γ, p₀) and (γ, p₁) reactions are 1.80±0.27 and 0.50±0.45 MeV-mb/sr, respectively. The results are discussed with the shell model theory by comparing with the (γ, p₀) cross section of the neighboring 4n-nucleus ²⁰Ne. A significant increase of the proton yield leaving the non-ground states is found at 25 MeV of the incident electron energy. This is discussed in terms of the core excitation effect.