Normalization and Minimum Values of the ²³⁹Pu Fission Cross Section

Measurements were carried out to accurately determine the shape of the fission cross section of ²³⁹Pu down to 0.025 eV in order to determine a more accurate normalization for previously reported fission cross-section measurements from Oak Ridge National Laboratory at higher neutron energies. Also, experimental backgrounds were carefully studied to verify the cross section between resonances. Results indicate a 3.0% higher normalization should have been used previously, and the low cross sections between resonances reported earlier were correct. New differential cross-section data were obtained from 0.002 to 100 eV.