Fragment flow and the multifragmentation phase space

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 4#pi# 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.)Available from TIB Hannover: RO 801(94-46) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman