Reliability of the data on the cross sections of the partial photoneutron reaction for 63,65Cu and 80Se nuclei

Abstract

The cross sections of partial photoneutron reactions are evaluated for the 63,65Cu and 80Se isotopes. The cross sections are free of systematic uncertainties from shortcomings of the experimental methods for neutron multiplicity sorting based on measurements of neutron energy used in experiments with quasimonoenergetic annihilation photon beams. An experimental-theoretical method is used to evaluate cross sections σeval(γ, in)= F theor σexp(γ, xn), where ratios F theor = σtheor(γ, in)/σtheor(γ, xn) = σtheor(γ, in)/σtheor[(γ, 1n) + 2(γ, 2n) + …] are calculated using a combined model of photonuclear reactions, and σexp(γ, xn) is the experimental cross section of the neutron yield reaction free from neutron multiplicity sorting problems. The cross sections are evaluated for reactions (γ, 1n) and (γ, 2n) for the 63,65Cu and 80Se isotopes, and for the total photoneutron reaction σ(γ, Sn) = σ[(γ, 1n) + (γ, 2n) + …]. It is shown that noticeable deviations of the experimental cross sections from the evaluated values result from the unreliable sorting of neutrons between the channels with multiplicities 1 and 2.