Reliability of Results of Photonuclear Experiments for Ni

The reliability of experimental data on the cross sections ( ) and ( ) partial reaction cross sections measured for Ni nuclei in beams of bremsstrahlung gamma radiation and beams of quasimonoenergetic annihilation photons is analyzed on the basis of objective physical criteria. It is found that the data obtained using bremsstrahlung gamma radiation do not satisfy physical criteria and are obviously unreliable. At the same time, it is shown that the reliability of the data obtained with beams of quasimonoenergetic photons by means of photoneutron multiplicity sorting is questionable. New cross sections of partial and total photoneutron reactions on Ni nuclei were obtained by the experimental–theoretical evaluation method based on simultaneously employing the experimental neutron yield cross section, which is independent of the problems of experimental determination of neutron multiplicities, and the results of calculations within the combined photonuclear reaction model (CPNRM). Significant discrepancies between experimentally measured and evaluated cross sections are analyzed in detail. It is shown that the discrepancies in question are due primarily to misinterpreting a significant number of neutrons from the ( ) reaction as those that originate from the ( ) reaction.