Adil Bahalim

1
Using GEMINI to study multiplicity distributions
of light charged particles and neutrons
Adil Bahalim Davidson College Dr. Joseph Natowitz
(Advisor), Dr. Seweryn Kowalski (Mentor) Summer
REU 2005 TAMU Cyclotron Institute
Background
Reconstruction
Heavy Ion Collisions
AMD Model Reconstruction

• Main hurdle is secondary decay (intermediate mass
  fragments) which makes it difficult to
  reconstruct primary fragments
• Antisymmetrized Molecular Dynamics (AMD)
  calculations used have shown to be good models
  for reconstruction
• Mean multiplicities (obtained from experiment)
  and distributions widths (difficult to obtain) of
  LPs are used as input parameters in GEMINI
• GEMINI is a statistical modeling code that uses
  the Monte-Carlo method to simulate sequential
  binary decays of nuclei

Procedure
Distribution Widths vs. Mean Multiplicities
GEMINI Simulations

• Simulated 1000 decay events for each nucleus from
  Z3 to Z40 with at least one from each
• Stability line (i.e. Z N)
• Proton-rich side ( Z gt N)
• Neutron-rich side (N gt Z)
• Excitation energies ranged from 2 to 5 MeV/amu in
  .5 MeV/amu increments
• Assumed constant inverse level density parameter
  (8)

Results
Conclusion
Best Fit Function at Exc. Energy 3 MeV/amu
Neutron Power-Function Parameters A B (yAxB)

• As expected, we found the relation between the
  mean multiplicities and distribution widths of
  the LCPs and neutrons
• These relations can be used as references to
  determine the distribution widths from the
  experimental data on mean multiplicities and
  implement them as input parameters for the
  reconstruction models