Bombarding energy dependence ofEr168(d, t)transitions

Abstract

Angular distributions have been measured for transitions populating residual states in $^{167}\mathrm{Er}$ through the $^{168}\mathrm{Er}(d, t)$ reaction at ${E}_{d}=15, 13, 11, \mathrm{and} 9$ MeV. Many of these transitions were previously seen to have angular distribution shapes which agreed with distorted-wave Born-approximation predictions at 17 MeV and these transitions also agree well with distorted-wave Born-approximation predictions at the lower bombarding energies. A small but significant number of transitions exhibited anomalously shaped angular distributions at 17 MeV and these continue to have anomalous angular distributions at the lower bombarding energies. Spectroscopic factors do not vary significantly over the bombarding energy range $9\ensuremath{\le}{E}_{d}\ensuremath{\le}17$ MeV. Spectroscopic factor disagreements between recent analyses of 17 MeV angular distributions and previously reported analyses of individual spectra at 12 MeV presumably do not result from a bombarding energy dependence but rather from the large uncertainties inherent in applying the distorted-wave Born-approximation analysis without having complete angular distributions.NUCLEAR REACTIONS $^{168}\mathrm{Er}(d, t)$, ${E}_{d}=15, 13, 11, \mathrm{and} 9$ MeV measured $\ensuremath{\sigma}(\ensuremath{\theta})$; DWBA analysis, deduced levels, $l$ values, spectroscopic factors. Enriched targets.