Measurement and Resonance Analysis of Neutron Transmission Through Uranium-238

Neutron transmissions through 0.076-, 0.254-, 1.080-, and 3.620-cm-thick samples of isotopically enriched ²³⁸U have been measured from 0.88 to 100.0 keV using a time-of-flight technique over a path length of 150 m, the ORELA pulsed neutron source, and a 13-mm-thick lithium-glass detector. To obtain resonance parameters, these transmissions from 0.88 to 4.00 keV have been simultaneously least-squares shape-fitted with a multilevel Breit-Wigner cross-section formalism. In general, large neutron widths are obtained, resulting in an s-wave strength function of (1.208 ± 0.045) × 10⁻⁴ over the interval from 0.0 to 4.0 keV. An absolute energy scale accurate to 2 parts in 10 000 was established.