Undergraduate Investigations of the Fusion of ^6He with ^209Bi Near and Above the Barrier

The effect of the neutron-skin nature of ^6He on the fusion cross section was investigated by measuring the four-neutron(P.A. DeYoung, et al.), Phys. Rev. C58, 3442 (1998.), three neutron(J.J. Kolata, et al.), Phys. Rev. Lett. 81, 4580 (1998)., and two-neutron decay channels following fusion. The measurements were made at Notre Dame with the TwinSol system. The beam energies of the measurements span a range of 19 to 31 MeV. Overall, a significant enhancement of the total fusion cross section was observed yet the two-neutron channel seemed not to be enhanced. The existence of a high-spin isomeric state in the residual nucleus formed following three-neutron evaporation allows one to investigate the spin distribution of the compound nucleus(P.A. DeYoung, et al.), Phys. Rev. C62, 047601 (2000).. These results contradict the expectations resulting from an enhanced fusion cross section. The measured cross sections and compound-nucleus spin information will be compared to statistical model calculations. In addition to a discussion of the fusion of ^6He, the benefits, struggles, rewards, and difficulties associated with undergraduate research will be presented along with some insight into what is required to make undergraduate research a successful experience. Supported by the National Science Foundation; PHY9870262.