[en] Energy spectra and charge distributions have been measured for multifragment disintegrations in Au + Au collisions at E/A = 100, 250, and 400 MeV. Energy spectra and mean transverse energies determined for fragments emitted in mid impact parameter collisions at E/A = 400 MeV reveal significant contributions from preequilibrium emission. Emission occurs for fragment energies that significantly exceed those predicted for an equilibrated decay of projectile-like residues

[en] Information about compressed high density nuclear matter can be obtained by studying collective flow exhibited by particles emitted in heavy ion induced reactions. Charged particles have been measured in 4π coverage for ¹⁹⁷Au + ¹⁹⁷Au collisions at E/A = 100, 250 and 400 MeV using the Miniball/Wall, the Catania Silicon-CsI array and the Aladin Spectrometer. Collective observables such as transverse sideward flow, radial flow and squeezeout will be discussed and the measured values will be compared to transport models

[en] Energy spectra and charge distributions have been measured for multifragment disintegrations in Kr + Au collisions at E/A = 35, 55, 70, 100, 200, and 400 MeV. Mean transverse energies determined for fragments significantly exceed those predicted for molecular dynamical and dynamical - statistical hybrid calculations. The measured fragment charge distributions are consistent with a open-quotes power-lawclose quotes falloff, that is more gradual than that consistent with recent open-quotes critical exponentclose quotes determinations. Comparison with statistical calculations reveal that such fragment distributions are strongly altered by the secondary decay of excited fragments

No abstract available

[en] Fragment distributions have been measured for Au + Au collisions at E/A 100 MeV and 1000 MeV. A high detection efficiency for fragments in nearly 4π geometry was obtained by combining the Aladin forward spectrometer system and the MSU-Miniball/WU-Miniwall array. At both energies the maximum multiplicity of intermediate mass fragments normalized to the size of the decaying system is about one IMF per 30 nucleons but the element distributions show significant differences. Within a coalescence picture the suppression of heavy fragments in central collisions at E/A = 100 MeV may be related to a reduction of the density in momentum space which is caused by the collective expansion velocity component. (orig.)

[en] Recent results from studies of the 1.8 - 4.8 GeV ³He + ^natAg, ¹⁹⁷Au reactions at LNS with the ISiS detector array have shown evidence for a saturation in deposition energy and multifragmentation from a low-density source. The collision dynamics have been examined in the context of intranuclear cascade and BUU models, while breakup phenomena have been compared with EES and SMM models. Fragment-fragment correlations and isotope ratios are also investigated. (K.A.)

No abstract available

[en] GeV light-ion-induced reactions offer a unique tool for preparing hot, dilute nuclear matter. Time evolution of nuclear multifragmentation in ³He + ^natAg and ³He + ¹⁹⁷Au reactions are investigated. Fragment-fragment correlations are studied in order to gain information on multifragmentation mechanism. (K.A.)

[en] The fragmentation of E/A=40 MeV ²⁰Ne projectiles into exit channels containing only p, d, t, ³He, α, ⁶He, ⁶Li, and ⁷Li fragments has been investigated. Relative shifts between the average longitudinal velocity of each fragment type were measured with ¹²⁰Sn and ¹⁹⁷Au targets. A post-breakup Coulomb acceleration component of these shifts was isolated. Its magnitude indicates that the projectile broke up while in near contact with the target. On the other hand, correlations between projectile fragments indicate that a significant fraction of these fragments are produced by the sequential decay of long- and short-lived unstable intermediates. A fully sequential decay process, although consistent with the experimental relative angle distributions, fails to reproduce the correlation function. Thus, a picture emerges of a prompt breakup step producing stable and unstable particles with the subsequent decay of the latter extending over a long time period

[en] The charge (Z) distributions from intermediate energy heavy-ion reactions depend upon the multiplicity n of intermediate mass fragments through a factor of the form e^-cnZ. Experimentally c starts from zero at low values of the transverse energy E_t and reaches a saturation value at high E_t. In a liquid-gas phase diagram c=0 for the saturated vapor, while c approx-gt 0 for the unsaturated vapor. It is suggested that in the c≅0 regime the source evaporates down to a sizable remnant, while for c approx-gt 0 the source vaporizes completely. Percolation of finite systems and nuclear evaporation portray a behavior similar to that observed experimentally. copyright 1996 The American Physical Society