Inclusive 7Be production cross section in the 8B + 208Pb system at the Coulomb barrier

Data for the angular distribution of the inclusive Be7 production cross section in the B8+Pb208 system at an incident energy of 50 MeV, equivalent to the nominal Coulomb barrier height, were measured at the CRIB facility. A coupled discretized continuum channel calculation was able to describe the data well, with no evidence for a significant contribution from nonelastic breakup. The energy dependence of the breakup cross section was investigated with the aid of previous measurements of the inclusive Be7 production cross section for the same system at a deep sub-barrier energy and at approximately four times the Coulomb barrier. We infer an increasing importance of nonelastic breakup as the incident energy is increased above the barrier, ruling out proton-stripping as a possible mechanism for this process due to the increasingly badly Q-matched character of this transfer reaction as the incident energy increases.