Simulated neutron-induced fission cross sections for various Pu, U, and Th isotopes

Neutron-induced fission cross sections have been extracted for targets of 240,241,243Pu, 234,236,237,239U, and 231,233Th from En=100 keV to ≅2.5 MeV using surrogate (t,pf) fission-probability data and a detailed statistical model to compensate for the difference between neutron-induced and (t,p) reactions. This paper extends the results of previous work on the 235U(n,f) cross section, which serves as a proof-of-principle study. The (n,f) cross sections are compared to earlier estimates based on the same surrogate data, but obtained using a more simplistic approach. The cross sections are also compared to accepted values where direct measurements exist and are consistently accurate to within 20% below En≅0.5 MeV and 10% at higher energies. The case of the 237U(n,f) cross section, simulated from surrogate (t,pf) data, is investigated in greater detail to reconcile contradictory measurements in the literature