Two-Neutron Quasiparticle States Observed inU236with the (d,p) Reaction

Abstract

Energy levels in the nucleus $^{236}\mathrm{U}$ have been studied with the $^{235}\mathrm{U}(d,p)^{236}\mathrm{U}$ reaction at bombarding energies from 12 to 16 MeV. The reaction products were analyzed with a split-pole magnetic spectrograph. The strongest transitions are those that lead to two-neutron quasiparticle states. Four rotational bands built upon the ${\frac{7}{2}}^{\ensuremath{-}}[743]\ifmmode\pm\else\textpm\fi{}{\frac{1}{2}}^{+}[631]$ and ${\frac{7}{2}}^{\ensuremath{-}}[743]\ifmmode\pm\else\textpm\fi{}{\frac{5}{2}}^{+}[622]$ configurations were identified. The bandheads for the ${K}^{\ensuremath{\pi}}={1}^{\ensuremath{-}},{4}^{\ensuremath{-}},{3}^{\ensuremath{-}},\mathrm{and} {6}^{\ensuremath{-}}$ bands are found to be at 970, 1054, 1192, and 1472 keV, respectively. The single-particle cross sections were extracted from the measured cross sections to the members in the rotational bands that involve the ${\frac{1}{2}}^{+}[631]$ orbital. Disagreement with calculated single-particle cross sections was found similar to the corresponding disagreement for cross sections extracted from the data on population of this orbital by transfer reactions on even-even targets. Me asured energy splittings in both $^{236}\mathrm{U}$ and $^{234}\mathrm{U}$ are compared with calculated values.