Absolute Neutron Fission Cross Sections of ²³⁵U, ²³⁸U, and ²³⁹Pu at 13.9 and 14.6 MeV

Measurements of the absolute neutron fission cross sections of ²³⁵U, ²³⁸U, and ²³⁹Pu have been made at 13.9 and 14.6 MeV with a double 4π ionization chamber. The associated particle method with the time-of-flight technique was used. Our final values of σ_nf(²³⁵U), σ_nf(²³⁸U), σ_nf(²³⁹Pu), σ_nf(²³⁸U)/σ_nf(²³⁵U), and σ_nf(²³⁹Pu)/σ_nf(²³⁵U) are compared to previous data.