DEEP SPALLATION OF MEDIUM MASS ISOTOPES BY PROTONS

Spallation systematics have been extended into the deep spallation mass region. Production cross sections of scandium radioisotopes from 0.8 GeV protons on Y-89, Mo-92, Mo-96, Mo-100 and Te-130 targets were measured and the cross sections were used to generate isobaric yield curves at A(p) =47. In the latter target, this corresponds to a mass loss of > 80 nucleons. At approximately 10 MeV/nucleon and for products outside the multifragmentation region, this is an extreme manifestation of the spallation process. The results prove to fit smooth extrapolations from trends developed in earlier work on less deep spallation. The influence of target composition is still evident even from Te-130, in contrast to expectations, based on evaporation considerations, that this so-called memory effect would wash out.