He4(γ,p)tReaction for Photon Energies Between 180 and 320 MeV

The differential cross section for the reaction ${}_{}{}^4{}_{}{}^{}\mathrm{He}(\gamma ,p)t$ was measured in a spark chamber experiment for photon energies between 180 and 320 MeV and proton c.m. angles between 60 and 120°. The results show that the cross section continues to decline with increasing energy. No evidence of a peak was found in the region of the first pion-nucleon resonance. An empirical function, involving the nucleon momentum distribution in the nucleus, was derived from a simple model of the photodisintegration process, and was used to correlate the observed differential cross sections over a large range of energy and angle.