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

Neutron-induced fission cross sections have been extracted for targets of ${}^{240,241,243}\mathrm{Pu},$ ${}^{234,236,237,239}\mathrm{U},$ and ${}^{231,233}\mathrm{Th}$ from $E_n=100\mathrm{}\mathrm{keV}$ to $\approx 2.5\mathrm{MeV}$ using surrogate $\mathrm{}(t,pf)\mathrm{}$ fission-probability data and a detailed statistical model to compensate for the difference between neutron-induced and $\mathrm{}(t,p)\mathrm{}$ reactions. This paper extends the results of previous work on the ${}^{235}\mathrm{U}\mathrm{}(n,f)\mathrm{}$ cross section, which serves as a proof-of-principle study. The $\mathrm{}(n,f)\mathrm{}$ 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 $E_n\approx 0.5\mathrm{MeV}$ and 10% at higher energies. The case of the ${}^{237}\mathrm{U}\mathrm{}(n,f)\mathrm{}$ cross section, simulated from surrogate $\mathrm{}(t,pf)\mathrm{}$ data, is investigated in greater detail to reconcile contradictory measurements in the literature.