Ratio of the ternary-to-binary fission cross sections induced by thermal and resonance neutrons in ²⁴¹Pu

The ternary-to-binary fission cross-section ratio (T/B) was determined for ²⁴¹Pu for neutron induced fission in the energy region from 0.01 eV to 50 eV. The ternary and binary fission time-of-flight spectra were recorded at a 8.1 m flightpath at the CBNM Linac with a bank of four large gold-silicon surface-barrier detectors viewing a 1 mg/cm^{2 241}Pu target. The ternary alpha pulse-height spectrum in the neutron energy region of interest was checked continuously. From the time-of-flight spectra the ratios of the areas of the strongest resonances in ternary and in binary fission were calculated; in the neutron energy region from 0.01 to 0.5 eV ratios were calculated for 18 zones throughout the spectrum. In the energy region from 1 to 50 eV the T/B ratio varies significantly from resonance to resonance, allowing a classification into a "high" and a "low" group. Although the statistical accuracy is poorer in the region below 1 eV we deduce from these T/B data that the 0.260 eV resonance probably belongs to the "high" group and also that there is only a slight difference between the T/B value at 0.260 eV and at thermal energy. We correlate these T/B values with the resonance spin J in terms of the channel theory of fission.