Energy Dependence of Fission Product Yields from ²³⁵U, ²³⁸U and ²³⁹Pu with Monoenergetic Neutrons between thermal and 14 MeV

Under a collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi-monoenergetic neutron beams for three actinide targets, ²³⁵U, ²³⁸U and ²³⁹Pu, between thermal and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and γ-ray counting. γ-ray counting of the activation target was performed on well-shielded HPGe detectors over a period of two months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6, 5.5, 7.5, 9 and 14.8 MeV. Preliminary results from thermal irradiations at the MIT research reactor will also be presented.