Supervisors info:
Γεώργιος Α. Σουλιώτης, Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Summary:
Nucleonic matter behaves as a homogeneous quantum liquid (Fermi liquid). However,
finite nuclei transiently behave as clusters of protons and neutrons. At present, there is a
renewed interest in clustering phenomena, both experimental and theoretical. While the
origin of nuclear clustering stems from the effective nuclear interaction, the detailed
mechanism of clustering remains elusive.
This work focuses on the study of the yields and the momentum distributions of projectilelike fragments from the reaction of an 40Ar beam with a 64Ni target at 15 MeV/nucleon.
The original experimental data were obtained in previous works of our group with the
MARS spectrometer at the Cyclotron Institute of Texas A&M University. Here, we focused
our attention to the products that correspond to the pick-up or removal of light clusters (d,
t, 3He and 4He).
As a first step in this study, we compared the experimental momentum distributions with
calculations performed with the Deep Inelastic Transfer model (DIT) and the Constrained
Molecular Dynamics model (CoMD) followed by the de-excitation code GEMINI. The
calculations appear to describe a good part of the experimental distributions but are
unable to fully describe the quasielastic part. Tentatively, we ascribe this disagreement
to a contribution of a direct cluster transfer from the target to the projectile and vice versa.
It appears that peripheral collisions of heavy ions offer the proper conditions (i.e., gentle
excitation of the reaction partners) so that clustering may develop, and cluster transfer
may be favored. For this reason, a detailed investigation of the possibility of direct transfer
of clusters in this reaction is carried out. Comparing the experimental momentum
distributions to appropriate reaction models, as we indicated above, an attempt has been
made to gain valuable insight into the mechanism of clustering and cluster transfer in
peripheral collisions in the Fermi energy regime.
Keywords:
Cluster Transfer, Cluster Breakup, Momentum Distributions, Peripheral Collisions, Fermi Energy
