Dominance of strong absorption in /sup 9/Be + /sup 28/Si elastic scattering. [121 and 201. 6 MeV: angular distribution, optical model]

Because the character of the scattering changes markedly from /sup 6/Li to /sup 12/C projectiles, a study of the /sup 9/Be + /sup 28/Si system was undertaken to examine the transition region. Data were measured at 121.0 and 201.6 MeV. Low-energy data of other investigators were used to carry out global optical model searches. It was found that the elastic scattering of /sup 9/Be from /sup 28/Si is dominated at all energies by relatively strong absorption. This removes much of the sensitivity to the real potential, and even elastic scattering data spanning a range of energies from 13 to 201 MeV do not allow a unique determination of the potential parameters. There is at least circumstantial evidence that /sup 6/Li scattering at low energies (and by implication also /sup 9/Be scattering) may be strongly influenced by breakup processes, although it is not clear that the mechanism is the same. 3 figures, 1 table. (RWR)