He4(γ,p)-to-(γ,n) cross-section ratio

We have measured the cross-section ratio $\frac{\sigma (\gamma ,{}_{}{}^3{}_{}{}^{}\mathrm{H})}{\sigma (\gamma ,{}_{}{}^3{}_{}{}^{}\mathrm{He})}$ for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ from 31 to 51 MeV with an incident bremsstrahlung beam and a collimated solid-state telescope at 90° laboratory angle. The results obtained from these data for the total cross-section ratio are consistent with unity for most of the energy range covered, but deviate from this value in the energy region near 44 MeV.