Proton momentum spectra in high-energy reactions of 9Be and 12C with quasimonochromatic photons

Momentum spectra of protons emitted at three lab angles 23°, 55° and 130° in high-energy photoreactions of ⁹Be and ¹²C are studied by using tagged photons in the energy range between 360 and 600 MeV. At 23° and 55°, we observe a structure which may be ascribed to protons from quasifree production of a single pion and those from quasideuteron photodisintegration, while at 130°, the spectra are predominantly due to protons resulting from intranuclear multiple scattering. The results of an intranuclear cascade calculation are compared with the data.