JAEA-Conf 2011-002 - 日本原子力研究開発機構

27. Comparison of Neutron Production from Heavy-ion Reaction using
PHITS and FLUKA
Cheol Woo LEE, Young-Ouk LEE
Korea Atomic Energy Research Institute, 1045 Daeduck-daero, Yuseong-gu, Daejeon, Korea
e-mail: cwll@kaeri.re.kr
In this study, heavy ion transport codes, PHITS and FLUKA were compared in the view of the radiation
shielding. The neutron production rates were calculated using these two codes and the results were compared
with the measurement. C-12 ion beam with the energy of 400 MeV/n and graphite target was used in the
calculation of the neutron production. The angular distributions of the secondary neutrons from the thick target
were compared and applied in the shielding calculations. By using these neutron source terms, the differences of
the dose rate behind of the shield materials, concrete, due to the neutron spectrum was evaluated. The shielding
design margin for the n-TOF experimental room using heavy ion beam in the accelerator facility in Korea was
evaluated.
I. Introduction
With increasing multi-purpose use of high energy heavy ion accelerators, secondary particle production and
transport by high-energy heavy ions are an important issue in the design of the heavy ion accelerator rooms and
facility. At present, the development of a heavy ions accelerator with the acceleration energy of 400 MeV/n is
under consideration in Korea. And we have a plan to build a n_TOF measurements room in the heavy ion
accelerator facility. But there have been no experience to construct a heavy ion accelerator of the high energy
above 100 MeV/n and perform the radiation shielding design in Korea.
This study is a preliminary analysis of the simulation codes for the heavy ion transport through the benchmark
calculations for the evaluation of the secondary radiation source terms and the difference of the calculation for
the shielding design.
II. Calculations and Results
JAEA-Conf 2011-002
Heavy-ion transport codes containing an event generator and physics models to simulate the heavy-ion
transport and nuclear-nuclear reactions requires following some features.
- reliable description of cross-sections and particle yields from a fraction of eV to TeV for heavy-ion projectiles
- leading particles (elastic, diffractive and inelastic)
- evaluate nuclide inventory or residuals
- simulate electromagnetic process and describe the magnetic field for charged particles
There are many Monte Carlo codes satisfying these requirements like as FLUKA, PHITS, GEANT4,
MARS15, MCNPX and SHIELD. Of these, FLUKA and PHITS were selected in this study considering
benchmarking conditions, geometrical model, kinds of heavy ions, measurements for benchmarking, energy of
particles, etc.
The inelastic interaction of the incoming projectiles and the target nuclei interact leads to the production of
secondary particles via different processes, such as fragmentation, fusion, Fermi break-up, and de-excitation. The
produced particles are mostly protons, neutrons and light fragments. The secondary neutrons are more important
in the view of the prompt radiation shielding.
The production yields of the secondary neutrons, mostly differential in both, energy and angle are compared by
using the three codes. These simulations can also be divided in two categories.
The first one is a thin target which thickness is in the order of one interactions length. The comparisons of the
results from thin target are very valuable assessing the quality of the models of a Monte Carlo particle code and