## 4 Effective Attenuation Factor for Layered Composites
\begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Material**} & \multirow{2}{*}{
\begin{tabular}{c} **\(\gamma\)-Ray** \\ **Energy** \\ **[MeV]** \\ \end{tabular} } & \multicolumn{5}{c}{**Linear Attenuation Coefficient [cm\({}^{-1}\)]**} \\ \cline{3-8}  & & **1:9** & **3:7** & **5:5** & **7:3** & **9:1** \\ \hline \multirow{8}{*}{PE/concrete} & 1 & 0.128 & 0.119 & 0.110 & 0.101 & 0.092 \\ \cline{2-8}  & 10 & 0.089 & 0.084 & 0.079 & 0.074 & 0.069 \\ \cline{2-8}  & 30 & 0.084 & 0.079 & 0.075 & 0.071 & 0.066 \\ \cline{2-8}  & 50 & 0.078 & 0.074 & 0.071 & 0.068 & 0.064 \\ \cline{2-8}  & 80 & 0.066 & 0.065 & 0.064 & 0.062 & 0.061 \\ \cline{2-8}  & 100 & 0.059 & 0.059 & 0.059 & 0.059 & 0.059 \\ \hline \multirow{8}{*}{PE/copper} & 1 & 0.369 & 0.307 & 0.244 & 0.181 & 0.118 \\ \cline{2-8}  & 10 & 0.244 & 0.205 & 0.165 & 0.126 & 0.087 \\ \cline{2-8}  & 30 & 0.213 & 0.180 & 0.147 & 0.114 & 0.081 \\ \cline{2-8}  & 50 & 0.164 & 0.142 & 0.119 & 0.097 & 0.074 \\ \cline{2-8}  & 80 & 0.105 & 0.095 & 0.085 & 0.075 & 0.065 \\ \cline{2-8}  & 100 & 0.074 & 0.071 & 0.067 & 0.064 & 0.061 \\ \hline \multirow{8}{*}{PE/lead} & 1 & 0.657 & 0.530 & 0.404 & 0.277 & 0.150 \\ \cline{2-8}  & 10 & 0.426 & 0.346 & 0.266 & 0.187 & 0.107 \\ \cline{2-8}  & 30 & 0.344 & 0.282 & 0.220 & 0.158 & 0.095 \\ \cline{2-8}  & 50 & 0.277 & 0.229 & 0.182 & 0.134 & 0.087 \\ \cline{2-8}  & 80 & 0.208 & 0.175 & 0.142 & 0.109 & 0.077 \\ \cline{2-8}  & 100 & 0.175 & 0.149 & 0.123 & 0.098 & 0.072 \\ \hline \multirow{8}{*}{PE/tungsten} & 1 & 1.019 & 0.812 & 0.605 & 0.398 & 0.191 \\ \cline{2-8}  & 10 & 0.671 & 0.536 & 0.402 & 0.268 & 0.134 \\ \cline{1-1} \cline{2-8}  & 30 & 0.583 & 0.468 & 0.352 & 0.237 & 0.122 \\ \cline{1-1} \cline{2-8}  & 50 & 0.513 & 0.413 & 0.313 & 0.213 & 0.113 \\ \cline{1-1} \cline{2-8}  & 80 & 0.444 & 0.358 & 0.273 & 0.188 & 0.103 \\ \cline{1-1} \cline{2-8}  & 100 & 0.410 & 0.332 & 0.254 & 0.176 & 0.098 \\ \hline \end{tabular}
\end{table} 
Table 3: Calculated Linear attenuation coefficient of laminated composites. Since the thickness of the designed composite material is 20 cm, the case where the calculated value is thinner than this and can cover more than 99.99% was excluded from the simulation. PE/concrete and PE/copper composites all had t\({}_{99,99}\) values of 20 cm or more regardless of the conditions, but in the case of PE/lead and PE/tungsten composites, t\({}_{99,99}\) values were calculated to be less than 20 cm under some conditions. (Table 4). Figure 6 shows the simulation results of linear attenuation coefficient of a 20 cm layered composite. The change in the linear attenuation coefficient of the composite material according to the layered structure was very small. However, it was confirmed that the linear attenuation coefficient of the entire composite material changed slightly as the number of layers of the layered composite material increased when PE and materials with a large difference in linear attenuation coefficient were compounded. In addition, although it cannot be said that there is a specific trend, it was found that gamma rays are refracted at the interface of the two materials as they pass through the composite material, and thus are affected by energy. Since this composite material has a layered structure, an interface exists