### 1. INTRODUCTION

^{-1}

^{238}U,

^{86}Kr,

^{48}Ca, and

^{16}O for an IF target and 600 MeV protons for an ISOL target and the uSR facility

^{1)}. With the increase in the number of particle accelerator facilities under either operation or construction, the accurate simulation using Monte Carlo codes become more important in the shielding design and radiation safety evaluation of accelerator facilities. The physics models which are used in Monte Carlo codes are critical factors to determine the secondary neutron production and the induced radioactivity of radiation shielding analysis.

### 2. MATERIALS AND METHODS

### 2.1 Physics models in MCNPX

^{3)}2) can be used. Second, for fission-evaporation, Dresner-RAL (Dresner evaporation model (associated with Rutherford Appleton laboratory fission by default)

^{4)}3), Abrasionablation model (ABLA) [9, 10], and Oak Ridge national laboratory (ORNL)

^{5)}4) model can be chosen. Third, ISABEL or LAQGSM can be selected as light-ion and nucleon physics modules. These can be selected with two cards of MCNPX input, which are LCA and LEA. The combinations of physics models in MCNPX 2.7.0 for each spallation reactions were illustrated in Figure 1.

^{3}He, and alpha according to MCNPX user’s manual), ISABEL and LAQGSM model are available for the calculation. In the case of heavy-ions, however, whose mass number is over 4, LAQGSM is the only model that can handle all heavy-ion interactions in MCNPX.

### 2.2 Simulation conditions using MCNPX

#### 2.2.1 600 MeV protons on carbon

#### 2.2.2 290 MeV·n-1 oxygen ions on carbon

^{-1}oxygen ions and the size of carbon target was 5.0 cm×5.0 cm×1.5 cm (thickness) [2]. Six different scoring angles to the beam axis were 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, and 90 degrees. This calculation was also performed in two ways; using only physics models and using the mix and match method with the JENDL/HE-2007 for neutron and proton.

### 3. RESULTS AND DISCUSSION

### 3.1 600 MeV protons on carbon

### 3.2 290 MeV·n^{-1} oxygen ions on carbon

^{-1}oxygen ions on the carbon target. The MCNPX results were close to the experimental data at whole energy range but underestimated. In the FLUKA calculation, the C/E ratio around 40 MeV was relatively bigger than that of other energies. The calculated results using PHITS were found to overestimate normally. In those comparisons, the properties of three well-known Monte Carlo codes (MCNPX, PHITS, and FLUKA) were described apparently for the heavy-ion induced neutron production.

### 4. CONCLUSION

^{-1}oxygen ions irradiated to the carbon target. The calculations were carried out in two ways; using only physics models and using the mix and match methods.