Program - Brookhaven National Laboratory

Study of Various Potentials in Heavy-Ion Collisions at Intermediate Energies
Varinderjit Kaur, Suneel Kumar, School of Physics and Materials Science, Thapar University, Patiala
(Punjab).
Heavy-ion collisions have always captured a central place in nuclear physics mainly due to the wider
domain of physics it caters. Right from low energy to the ultra-relativistic energies, a large number
of new phenomena have been predicted. The reaction dynamics in heavy-ion collisions at intermediate
energies has been used extensively during the last three decades to understand the nature of nuclear
matter at extreme conditions of temperature and density. The phenomena that are mainly observed
in this energy range are multi-fragmentation, collective flow and nuclear stopping etc. Among these
observables, collective transverse in-plane flow has been found to be of immense importance [1, 2]. Lots of
experiments have been performed and number of theoretical attempts have also been employed to explain
and understand transverse in-plane flow. Collective flow is negative at low incident energies whereas it
is positive at a reasonable higher incident energies. At a particular energy, however, a transition occurs.
This transition energy is known as balance energy. This balance energy has been subjected to intensive
theoretical calculations using variety of equations of state as well as NN cross-sections [1, 2]. Interestingly
none of these studies take the effect of various potentials such as Skryme potential (density dependent),
Yukawa potential (surface dependent), Coulomb potential, symmetry potential, and momentum dependent
interactions etc. into account. Here, our aim is to pin down the contribution of various potentials in
transverse in-plane flow and hence balance energy by using the reactions of Ni58 + Ni58 and Fe58 +
Fe58 between the incident energy range from 50 MeV/nucleon to 150 MeV/nucleon. The study has been
performed within the framework of Isospin-dependent Quantum Molecular Dynamics (IQMD) model [3].
The impact parameters are guided by the experimental study of R. Pak et al. [4].
[1] J. Aichelin, Phys. Rep. 202, 233 (1991); A. D. Sood and R. K. Puri, Phys. Lett. B 594, 260 (2004).
[2] G. D. Westfall et al., Phys. Rev. Lett. 71, 1986 (1993). [3] C. Hartnack et al., Eur. Phys. J. A 1, 151
(1998). [4] R. Pak et al., Phys. Rev. Lett. 78, 1022 (1997); ibid. 78, 1026 (1997).
PR 80
Interaction of Fast Nucleons with Actinide Nuclei Studied with Geant4
Yury Malyshkin, Igor Pshenichnov, Igor Mishustin, Walter Greiner, Frankfurt Institute for Advanced
Studies, J.-W. Goethe University, 60438 Frankfurt am Main, Germany. Timothy Hughes, Oliver Heid,
Siemens AG, 91052 Erlangen, Germany.
We model interactions of protons and neutrons with energies from 1 to 1000 MeV with uranium and
americium nuclei, as well as with extended targets made of such fissile materials. The calculations are
performed with the Monte Carlo model for Accelerator Driven Systems (MCADS) [1, 2] which is based on
the Geant4 toolkit [3] version 9.4. This toolkit is widely used for Monte Carlo simulations in particle and
nuclear physics already for a decade. Previously it was applied to transport particles in materials containing
nuclei not heavier than uranium (Z