Fission Cross Section ofPu241

The low-energy neutron-induced fission cross section of ${\mathrm{Pu}}^{241}$ has been measured from 2-100 eV, with sufficiently high resolution to permit multilevel analysis below neutron energies of 36 eV. The results of the analysis are consistent with the assumption that the resonances can be separated into two groups having different average fission widths, and that the interference effects can be described by a single-fission channel for each group. The properties of resonances from 12-36 eV are found to be very similar to those below 12 eV, described previously. On the basis of the parameters obtained, the number of effective fission channels is discussed.