请给我mcnp5建立球形光中子靶源,内层为Na,半径1.19cm,中间层为Al,厚度0.32cm,外层为Be,厚度0.32cm,建立模型并输出中子能谱的代码
时间: 2024-10-08 15:01:51 浏览: 9
在MCNP5中建立这样一个球形中子靶源的模型,你需要遵循以下步骤,并注意每个部分的名称和尺寸都是关键:
1. **开始头文件**:
```mcnp
!*mcnp5
!title Neutron Target Model
```
2. **材料定义**:
```mcnp
MAT Na 5001 23 23 23.0 1.0 0.0 1.0 1.0 1.0 1.0 # Sodium (Na-23)
MAT Al 13001 27 27 26.982 0.0 0.0 1.0 0.12 0.082 1.0 # Aluminum (Al-27)
MAT Be 40001 4 4 9.0122 0.0 0.0 1.0 0.12 0.082 1.0 # Beryllium (Be-9)
```
3. **几何描述**:
```mcnp
SHELL sphere NaSource 0 0 0 1.19 # Inner sodium layer
SHELL sphere AlShell 0 0 0 1.19 1.51 # Aluminum layer (radius = inner + Al thickness)
SHELL sphere BeShell 0 0 0 1.51 2.24 # Beryllium layer (radius = aluminum + Be thickness)
```
4. **设置中子源**:
```mcnp
SOURCE neutrons 0 0 0 0 0 1E-6 # Point source at the center of the sphere
```
5. **追踪参数**:
```mcnp
FLUX 1E5 neutrons/cm^2-s # Set flux or number of neutrons per second
```
6. **输出中子能谱**:
```mcnp
SCORE neutron_spectrum output.neutron_spectrum # Request a neutron energy spectrum output
```
7. **结束文件**:
```mcnp
END
```