Neutron resonance spectroscopy for n+204Pb: Total and differential elastic scattering cross sections

We have measured the neutron total and elastic scattering cross sections for the 204Pb+n reaction over the neutron energy range 35-1000 keV. Neutron resonance widths and energies have been deduced for 1357 resonances from an R-matrix analysis of the total cross section data. Of this number 317, 424, and 617 are due to s-, p-, and d-wave interactions, respectively, with the parity assignments based mainly upon resonance asymmetries observed in the scattering data. The level densities and strengths of all partial waves are uniform up to a neutron energy of 500 keV. The s-, p-, and d-wave strength functions for this energy region are (in units of 10-4) 1.3±0.2, 0.19±0.02, and 1.0±0.1, respectively. If the strengths are calculated over the entire energy range the values for s and d waves are reduced by 35% and 12%, respectively, while that for p waves is increased by 40%. The s-, p-, and d-wave level densities (in keV-1) are 0.33±0.03, 0.44±0.02, and 0.68±0.01, respectively