The energy spectra of fast photoprotons from ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ have been measured for a bremsstrahlung energy between 50 and 80 MeV. The analysis of the obtained cross section shows a strong direct emission from the $1p$ shell.

• Received 18 September 1968

DOI:https://doi.org/10.1103/PhysRevLett.21.1266