Near- and sub-barrier fusion of 6He+40Ar

A measurement of the fusion cross section for 6He + 40Ar near and below the Coulomb barrier has been performed using a 6He beam from the UND/Um radioactive beam facility. The 6He nucleus is thought to have a neutron skin surrounding a 6He core. If this is the case, then Coulomb polarization of the core relative to the halo might result in neutron flow along a neck, and therefore to a large enhancement of the sub-barrier fusion cross section. 6He nuclei, of incident energy 10.05 ± 0.44 MeV, were directed into a segmented ionization counter (MUSIC) filled with P10 at 40 torr. The 40Ar in the detector gas served also as the target nuclei. 6He energies in the 50-cm active length of the detector varied from 7.75 MeV down to 3.05 MeV. Calculations indicate that fusion events should be distinguishable from most non-fusion events on the basis of energy deposition patterns in the ten MUSIC detector segments. For some large-angle scattering events a more elaborate analysis involving detailed Monte Carlo simulation of the various reactions is necessary