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

Resonances in both the capture and total cross sections for ³²S, ⁵⁶Fe, ²⁰⁶Pb, ²⁰⁷Pb, and ²⁰⁸Pb 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 $l>0$ neutrons, were found in all of these nuclei. The p-wave level density for ²⁰⁶Pb and ²⁰⁷Pb 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 lₙ=0 versus two lₙ=1 resonances for ²⁰⁷Pb targets differed by a factor of 10. The effective nuclear radius, R^', was found to be (8.5±{}0.2)F(²⁰⁶Pb), (9.5±{}0.3)F(²⁰⁷Pb), and (8.4±{}0.3)F(²⁰⁸Pb), giving an average of (8.8±{}0.3)F which is in good agreement with an optical-model prediction of 8.7F.