Abstract
Background: Li is one of the most studied halo nuclei. The fusion of Li with Pb is the subject of a number of theoretical studies with widely differing predictions, ranging over four orders of magnitude, for the fusion excitation function.
Purpose: The purpose was to measure the excitation function for the Li Pb reaction.
Methods: A stacked foil and degrader assembly of Pb targets was irradiated with a Li beam producing center-of-target beam energies from above-barrier to near-barrier energies (40–29 MeV). The intensity of the Li beam (chopped) was 1250 particles/s and the beam on-target time was 34 h. The decay of the stopped evaporation residues (EVRs) was detected in an -detector array at each beam energy in the beam-off period (the beam was on for 5 ns and then off for 170 ns).
Results: The observed nuclidic yields of At and At are consistent with being produced in the complete fusion of Li with Pb. The observed yields of At appear to be the result of the breakup of Li into , with the Li fusing with Pb. The magnitudes of the total fusion cross sections are substantially less than most theoretical predictions.
Conclusions: It is possible to measure the EVR production cross sections resulting from the interaction of Li with Pb using current-generation radioactive beam facilities. Both complete fusion and breakup fusion processes occur in the interaction of Li with Pb. An important breakup process leads to the fusion of the Li fragment with Pb.
6 More- Received 27 August 2012
DOI:https://doi.org/10.1103/PhysRevC.87.044603
©2013 American Physical Society