Precise Uranium-235 Fission Cross-Section Measurements Below 1 keV

We have performed three measurements of the ²³⁵U fission cross section in the energy range from 0.02 eV to 1 keV. The averaged data are grouped into broad energy intervals to improve the statistical accuracy and to aid in the normalization of higher energy measurements. The uncertainty in the cross sections analyzed in this manner will permit normalization of the values at higher energy with an accuracy of about ±1%.