Pb206(α,d)Bi208at 48 MeV

Abstract

The $^{206}\mathrm{Pb}(\ensuremath{\alpha},\mathrm{d})^{208}\mathrm{Bi}$ reaction was investigated at 48.2 MeV with about 25 keV resolution. Angular distributions were obtained for 48 levels at excitation energies up to 5 MeV. Many previously unknown levels were seen and most seem to have two-particle---two-hole structure and spins above 6; however, the relatively structureless angular distributions permit only approximate $L$ assignments. Transitions to six low-lying one-particle---one-hole states were analyzed in detail. Distorted-wave Born approximation predictions agreed with the observed angular distributions, but the absolute cross sections computed from published $^{206}\mathrm{Pb}$ and $^{208}\mathrm{Bi}$ wave functions are generally larger than observed, particularly those for the ${J}_{max}$ states. Contributions of the dominant two-step sequential stripping channels to the one-step results were investigated. They were important and gave varying amounts of enhancement for all six levels. The observed quenching of the ${J}_{max}$ cross sections was not reproduced.