Photonuclear experiments: from the bremsstrahlung to the Compton backward scattering photons

The features of the methods for obtaining the information on photonuclear reaction cross sections using the beams of bremsstrahlung and quasimonoenergetic photons from the annihilation in flight of relativistic positrons with which such the absolute majority of such kind data was obtained in the nucleus excitation energy up to ∼40 MeV are discussed. It was shown that significant disagreements between the results of such experiments in cross sections absolute values and shapes are due to both methods definite shortcomings which to a certain extent can be overcome by using the beams of the photons from the processes of Compton backward scattering.