Skobeltsyn Institute of Nuclear Physics
Lomonosov Moscow State University

There are well-known systematic disagreements in partial photoneutron reaction cross sections
data obtained in experiments with quasimonoenergetic annihilation photons using methods of
neutron multiplicity sorting. Using proposed criteria we found that major sources of data large
systematic uncertainties come from certain shortcomings of experimental methods for outgoing
neutron multiplicity sorting. To develop methods of correcting the data obtained in various
experiments a new approach for their evaluation was developed in which the equations of a
combined model of photonuclear reactions are used to decompose the experimental total neutron
yield reaction cross section into contributions of partial reactions. Evaluated cross sections of
partial photoneutron reactions obtained by using such method are in agreement with
experimental data obtained by alternative experiments. Evaluated partial photoneutron rections
cross sections for 91,94Zr, 115In, 159Tb, 181Ta, 188,189,190,192Os, and 208Pb are presented.