High Energy Photoproton Production by 322-Mev Bremsstrahlung

The ejection of high energy protons from various materials by 322-Mev bremsstrahlung has been investigated using a detector telescope consisting of three liquid scintillators. Protons, above a minimum energy of 65 Mev, were distinguished from other particles by their dE/dx at a fixed range. At 70 Mev the angular distribution appears to be independent of nuclear complexity; the relative distributions from Li, C, and Ta have about the same shape. Distributions from C at 77, 127, and 174 Mev were measured between 11^∘{} and 45^∘{}. The data do not fit the predictions of a quasi-deuteron model, but adequate calculations require more knowledge of the deuteron photodissociation process. The yield at 45^∘{} for 72- and 142-Mev protons from various materials was found to be directly proportional to Z. The energy spectra of photoprotons from C have been measured at 45^∘{} and 90^∘{}. The absolute differential cross section for production of 72-Mev protons from C at 90^∘{} has been measured.