Comparative analysis of estimates of neutron radiative capture cross sections for the most important fission products

Abstract

We have reevaluated the neutron capture cross sections of the most important fission products in the neutron energy range from 1 to 1000 keV, taking account of the most recent experimental data. We also used all the available earlier measurements, part of which we renormalized to contemporary standards. The consideration of all the data which agree within 5–10% ensures estimates of high reliability. The analysis of the experimental data and the theoretical description of the cross sections using the method of maximum probability show that the current accuracy of the estimates of the neutron capture cross sections of fission products of the first group in the energy range from 1 to 1000 keV is 10–15%. Since this accuracy satisfies the requirements for the estimated of fission products [40], we recommend the inclusion of our results in the file of cross section values of the respective nuclei. A correct comparison with integral data requires taking account of the effects of resonance self-shielding of the cross sections. A preliminary comparison with integral data shows that it is necessary to reconcile the differential and integral measurements of the99Tc and109Ag cross sections. It is difficult to determine the errors of the recommended cross sections of fission products of the second and third groups, for which there is no direct experimental information on the average fast neutron capture cross sections. The possibility of an experimental test of the cross section estimates should be investigated. This question is particularly urgent for107Pd,131Xe, and135Cs, which belong to the first half of the list of the most important fission products.