R.W. Ingle

Measurement of the uranium-238 capture cross section for incident neutron energies up to 100 keV

AbstractThe neutron capture cross section of 238U was measured for incident neutron energies between 5 eV and 100 keV using a pulsed electron Linac neutron source and the time-of-flight technique. Capture gamma rays were detected by a large liquid scintillator located on a 40-m flight path. The incident neutron flux was monitored by a 10BF3 ionization chamber. The cross section was normalized by the saturated resonance technique.The data have uncertainties which increase from ∼5% at 1 keV to 10% at 100 keV. These data are compared with results from other measurements and with various evaluations.

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 /sup 238/U were measured from 0.88 to 100.0 keV by means of 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 were simultaneously least-squares shape-fitted with a multilevel Breil--Wigner cross-section formalism. In general, large neutron widths were obtained, resulting in an s-wave strength function of (1.208 +- 0.045) x 10/sup -4/ over the interval from 0.0 to 4.0 keV. An absolute energy scale accurate to 2 parts in 10,000 was established. 11 figures, 16 tables.

Measurement of the Uranium-238 Subthreshold Fission Cross Section for Incident Neutron Energies Between 0.6 and 100 keV

The neutron-induced /sup 238/U subthreshold fission cross section has been measured in the neutron energy range between 0.6 and 100 keV. A total of 28 fission clusters were identified. The well-known clusters at 721 and 1210 eV appeared resolved into their Class I components. Average /sup 238/U subthreshold fission cross sections were determined and compared with available results in the literature. The measurement is interpreted in terms of fission doorway (Class II levels) arising from the assumption of the existence of a double-humped fission barrier for the (/sup 238/U + n) compound nucleus at large deformations. On the basis of this model, several fission barrier parameters were determined.

Measurement of neutron transmissions from 0. 52 eV to 4. 0 keV through seven samples of /sup 238/U at 40 m

Neutron transmissions through 1.5-, 5-, 10-, 30-, 100-, 425-, and 1425-mil samples of depleted /sup 238/U were measured from 0.52 eV to 4.0 keV using the ORELA pulsed electron linac neutron source and time-of-flight technique with a 1-mm /sup 6/Li-glass detector with a flight path of 40 m. The measurements are tabulated and compared with transmissions calculated from the ENDF/B-IV total cross section. In addition, the 1425-mil transmission from 50 to 300 eV is compared with transmissions calculated by using multilevel formalisms, and some neutron widths are extracted with area analysis and compared with those from previous measurements. 14 figures, 10 tables. (auth)