4 research outputs found
Transition from participant to spectator fragmentation in Au+Au reactions between 60 A and 150 AMeV
Isotopic effects in multifragmentation and the nuclear equation of state
Isotopic effects in spectator fragmentations following heavy-ion collisions at relativistic
energies are investigated using data from recent exclusive experiments with SIS beams
at GSI. Reactions of 12C on 112,124Sn at incident energies 300 and 600 MeV per nucleon
were studied with the INDRA multidetector while the fragmentation of stable 124Sn and
radioactive 107Sn and 124La projectiles was studied with the ALADIN spectrometer.
The global characteristics of the reactions are very similar. This includes the rise and
fall of fragment production and deduced observables as, e.g., the breakup temperature
obtained from double ratios of isotope yields. The mass distributions depend strongly
on the neutron-to-proton ratio of the decaying system, as expected for a simultaneous
statistical breakup. The ratios of light-isotope yields from neutron-rich and neutron-poor
systems follow the law of isoscaling. The deduced scaling parameters decrease strongly
with increasing centrality to values smaller than 50% of those obtained for the peripheral
event groups. This is not compensated by an equivalent rise of the breakup temperatures
which suggests a reduction of the symmetry term required in a liquid-drop description of
the fragments at freeze-out
Spectator fragmentation induced by relativistic C projectiles
Matière NucléaireInternational audienc