Fragmentation at 20 to 43 MeV/nucleon

In contrast to the data obtained with 43 MeV/nucleon 20Ne, extraction of the widths from projectile-like fragments observed in the reactions of 20Ne with 197Au at 20 MeV/μ leads to values of 30 to 40 MeV/c. Taken together, these results indicate a very rapid change in the nature of the fragmentation process between 20 and 43 MeV/nucleon. We have attempted to pursue these investigations by extracting higher energy beams from the TAMU cyclotron. Beams of 107 particles/second of 22.5 MeV/nucleon 20Ne and 32.5 MeV/nucleon 10B have been obtained and used to study light particle emission in reactions with 181Ta. Spectra obtained in these studies are shown. Each of the spectra shows evidence of a high energy component peaking at energies somewhat below that corresponding to the projectile velocity. The highest energy component in the spectrum from the 20Ne experiment is probably not from simple fragmentation. The prominent high energy component observed in the 32.5 MeV/nucleon 10B experiments has a width parameter sigma0 = 40 MeV/c suggesting that the major broadening occurs rapidly above that energy. The data are summarized. This conclusion must be viewed as tentative since there may be significant differences between 10B and 20Ne projectiles