15 research outputs found
Comparative Study of Multifragmentation of Gold Nuclei Induced by Relativistic Protons, He, and C
Multiple emission of intermediate-mass fragments has been studied for the
collisions of p, He and C on Au with the setup FASA. The mean
IMF multiplicities (for the events with at least one IMF) are saturating at the
value of for the incident energies above 6 GeV. The observed IMF
multiplicities cannot be described in a two-stage scenario, a fast cascade
followed by a statistical multifragmentation. Agreement with the measured IMF
multiplicities is obtained by introducing an intermediate phase and modifying
empirically the excitation energies and masses of the remnants.
The angular distributions and energy spectra from the p-induced collisions
are in agreement with the scenario of ``thermal'' multifragmentation of a hot
and diluted target spectator. In the case of C+Au(22.4 GeV) and
He(14.6 GeV)+Au collisions, deviations from a pure thermal break-up are
seen in the energy spectra of the emitted fragments, which are harder than
those both from model calculations and from the measured ones for p-induced
collisions. This difference is attributed to a collective flow.Comment: 33 pages 15 figures, accepted in Nucl. Phys.
Nuclear multifragmentation and fission: similarity and differences
Thermal multifragmentation of hot nuclei is interpreted as the nuclear
liquid--fog phase transition deep inside the spinodal region. The experimental
data for p(8.1GeV) + Au collisions are analyzed. It is concluded that the decay
process of hot nuclei is characterized by two size parameters: transition state
and freeze-out volumes. The similarity between dynamics of fragmentation and
ordinary fission is discussed. The IMF emission time is related to the mean
rupture time at the multi-scission point, which corresponds to the kinetic
freeze-out configuration.Comment: 7 pages, 3 Postscript figures, Proceedings of IWM 2005, Catani
Thermal multifragmentation in p + Au interactions at 2.16, 3.6 and 8.1 GeV incident energies
Multiple emission of intermediate-mass fragments has been
studied for the collisions p + Au at 2.16, 3.6 and 8.1 GeV with the
FASA setup. The mean IMF multiplicities for events with at least one
IMF are equal to 1.7, 1.9 and 2.1 (0.2) respectively.
The multiplicity, charge distributions and kinetic energy spectra of
IMF are described in the framework of a intranuclear cascade model
followed by the statistical multifragmentation model. However,
between the two parts of the calculation the excitation energies and
the residual masses and charges are modified to take into account the
losses during expansion.
The results support a scenario of true thermal multifragmentation
of a hot and expanded target spectator