U238giant resonances and theU238(p,p′)reaction atEp=66MeV

Abstract

Measurements of inelastic proton spectra in the region 0-25-MeV excitation energy have been made for the ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}(p,p^{\prime })$ reaction using 66-MeV protons. Two new strongly collective excitation regions of ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ were discovered at $E_x\approx 1.6-2.0$ MeV and $E_x\approx 10-13$ MeV. The ≅1.8-MeV excitation region is complex, and its angular distribution is consistent with $L=3\mathrm{}$ and $L=2\mathrm{}$ groups. The collective resonance region at 10-13 MeV appears to have an $L=2\mathrm{}$ angular distribution with strength to exhaust most of the energy-weighted sum rule, although $L=3\mathrm{} \mathrm{and} 4$ components cannot be rigorously excluded. The remaining excitation region accounts for most of the cross-section strength in the reaction and consists of a relatively smooth continuum background. The results are discussed in terms of the Nilsson model.