Status of experimental photonuclear results

Abstract

Absolute majority of data on photonuclear reaction cross sections was obtained in experiments using bremsstrahlung and quasimonoenergetic photons produced at annihilation in flight of relativistic positrons. There are significant disagreements both in absolute value and shape between the results of experiments of both types. So, the pronounced structural features are clearly observed in the cross sections obtained using bremsstrahlung but those are practically absent in the cross sections obtained on the beams of annihilation photons. The disagreements in absolute values are definitely systematic: they are directly dependent on the data retrieval method and significantly exceed the statistical errors achieved in experiments. There are also the significant disagreements between the data obtained in experiments of the same type. In combined systematic investigations of many data on various photonuclear (primarily, photoneutron) reaction, both total and partial, cross sections the possible reasons for disagreements between the results of photonuclear experiments were found out, the status of those experiments and methods of accounting and elimination of observed disagreements are discussed.