Fast-Neutron Scattering from the 182, 184, and 186 Isotopes of Tungsten

The differential cross sections for the elastic and the inelastic scattering of fast neutrons from ${\mathrm{W}}^{182}$, ${\mathrm{W}}^{184}$, and ${\mathrm{W}}^{186}$ were experimentally determined at incident neutron energy intervals of $\stackrel{\mathrm{\sim }}{<}$ 25 keV from 0.3 to 1.5 MeV. The excitation, by inelastic scattering, of states in ${\mathrm{W}}^{182}$ was observed at 102±5 and 327±10 keV; in ${\mathrm{W}}^{184}$ at 110±5, 360±10, 901±10, 1003±10 and 1120±10 keV; and in ${\mathrm{W}}^{186}$ at 121±5, 398±10, 738±10, 863±10, 942±10 and 1035±10 keV. The differential elastic- and inelastic-scattering cross sections were measured at 8 or more angles between 27 and 150 deg by means of a multiangle fast time-of-flight system. The resolution was sufficient to resolve most of the scattered neutron groups. The experimental results were interpreted in terms of a deformed optical model, coupled-channel direct interaction, and Hauser-Feshbach theory. Good agreement with measurement was obtained when the effects of resonance-width fluctuations and correlations were included.