Photonuclear Experiments: From Bremsstrahlung to Backward Compton Scattering Photons

The features of methods for obtaining information on photonuclear reaction cross sections using beams of bremsstrahlung and quasimonoenergetic photons formed during the in-flight annihilation of relativistic positrons are discussed. These methods have provided the vast majority of data in the nuclear excitation energy up to \({\sim}40\) MeV. It is shown that significant disagreements between the results of such experiments, both in absolute value and shape, are due to certain shortcomings of both methods. These shortcomings can be to a certain extent eliminated by using beams of photons formed in the processes of backward Compton scattering.