(d, p) and (d, t) Reaction Studies of the Actinide Elements. I.U235

Abstract

Levels of the nucleus ${\mathrm{U}}^{235}$, populated in the reactions ${\mathrm{U}}^{234}(d, p){\mathrm{U}}^{235}$ and ${\mathrm{U}}^{236}(d, t){\mathrm{U}}^{235}$ induced by 12-MeV deuterons from the Argonne tandem Van de Graaff, were analyzed with a magnetic spectrograph. Most of the observed levels were identified as members of rotational bands built on the single-particle states of a deformed central field. The level assignments were made on the basis of relative populations of presumed members of each rotational band, ratios of the cross sections at 90° and 140°, and $\frac{(d, p)}{(d, t)}$ cross-section ratios. Pairing effects were calculated for the observed spectrum, and a single-particle scheme was extracted from the data. This single-particle scheme was compared with the calculations of Nilsson and Rost. Levels not predicted on the basis of the single-particle models were observed at excitations as low as 700 keV. Some of these levels, presumably vibrational excitations, were found to have cross sections comparable to those of single-particle states.