Measurement of the /sup 239/Pu fission cross-section and its ratio to the /sup 235/U fission cross-section in the energy range from 1 keV to 1 MeV

The cross-section for the /sup 239/Pu(n,f) reaction has been measured on the Harwell 45 MeV linac using the time-of-flight method. Fission events were recorded by detecting the prompt neutrons and the incident neutron flux spectrum was measured with a detector which was calibrated against two standard detectors. The cross-section was normalized in the 10 to 30 keV energy interval to agree with the recent evaluation of Sowerby et al. Comparison with this evaluation shows agreement to within 5% at energies above a few keV. The agreement with the ENDF/B-IV evaluation is generally within 4% throughout the complete energy range. A similar comparison is made for the ratio of the /sup 239/Pu and /sup 235/U fission cross-sections, obtained from the present measurement, and a previously published measurement of the /sup 235/U(n,f) cross-section made with the same equipment. 3 tables, 2 figures. (auth)