Subbarrier fusion in the systems 11,10Be+209Bi: the experimental data

The subbarrier fusion cross section has been measured in the system 11,10Be+209Bi. The data were collected at the RIKEN Ring Cyclotron with a total beam intensity of ∼10+5 Hz typical for such radioactive nuclear beams of first generation. The cross section accuracy is around 10 to 15 %. The two excitation functions look, within the statistical uncertainty very similar as well as the 9Be+209Bi one at difference with the expectations. This is triggering further theoretical analysis.