Abstract
Intermediate-mass fragments formed in reactions of ions with and targets have been studied at five energies between 0.48 and 3.6 GeV. Inclusive measurements show that as the bombarding energy increases, there is a strong enhancement in fragment cross sections and a trend toward isotropic angular distributions. Between 0.90 and 1.8 GeV, a change in the emission mechanism is suggested by (1) kinetic energy spectra with high-energy tails that become distinctly flatter, (2) a broadening of the spectral Coulomb peaks toward lower energies, and (3) charge distributions that become constant, exhibiting a power-law exponent τ≊2.0. Exclusive studies of the Ag system at 0.90 and 3.6 GeV detected multifragment events with multiplicities up to four. The probability for high-multiplicity events increases about 40-fold between 0.90 and 3.6 GeV. At both energies, the kinetic energy spectra depend on multiplicity, especially when triggering on backward-emitted fragments. For multiplicity three events, a rapidity analysis of the data at 3.6 GeV is consistent with a single, relatively low source velocity, ≊0.4 cm/ns. The data are compared with predictions of a coplanarity-sphericity calculation, the sequential statistical decay code GEMINI, and a hybrid intranuclear cascade/percolation model.
- Received 1 February 1993
DOI:https://doi.org/10.1103/PhysRevC.48.1092
©1993 American Physical Society