Resonance Neutron Capture and Transmission in Sulfur, Iron, and Lead

Resonances in both the capture and total cross sections for ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$, ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ were investigated in the energy range from 10 to 80 keV. Total and radiative widths, and in some cases spins and/or parities, were assigned, and isotopic identifications of resonances were made. Previously unknown resonances mostly due to $l>\mathrm{}0\mathrm{}$ neutrons, were found in all of these nuclei. The $p$-wave level density for ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$ and ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ was found to be more than twice as high as one would expect from the number of observed $s$ resonances. The total radiative widths for an $l_n=0\mathrm{}$ versus two $l_n=1\mathrm{}$ resonances for ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ targets differed by a factor of 10. The effective nuclear radius, $R^{\prime }$, was found to be (8.5±0.2)F(${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$), (9.5±0.3)F(${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$), and (8.4±0.3)F(${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$), giving an average of (8.8±0.3)F which is in good agreement with an optical-model prediction of 8.7F.