## 3 Results  
To improve the shielding performance and tensile strength of the RSF, a defoaming step in the pulverization and mixing process of the shielding material was inserted into the manufacturing process to improve the porosity. To observe the dispersion state of the manufactured RSF, nano-analysis SEM (SUPRA-55 VP, Zeiss, Oregon, USA) at 15 kV was used. Figure 2 shows an SEM image of air removal after blending with 25% BaSO\({}_{4}\) and polyethylene for 30 min, and an SEM image for no air removal. As shown in Figure 2, the SEM images of the RSF before and after air removal also showed differences in the flow ratio. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Tube Voltage (kVp)** & **Added Filter (mm Al)** & **Half Value (mm Al)** & **Effective Energy (keV)** \\ \hline
60 & 5.15 & 2.96 & 38.9 \\
80 & 5.15 & 3.87 & 46.3 \\
100 & 5.15 & 4.79 & 52.6 \\
120 & 5.91 & 6.04 & 58.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of effective energy to tube voltage. Figure 1: Configuration of the shielding experiment. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Characteristic Matter** & **Pb** & **Ba** & **Bi** & **W** \\ \hline Density (g/cm\({}^{3}\)) & 11.34 & 3.51 & 9.78 & 19.25 \\ Atomic mass (g/mol) & 207.2 & 137.3 & 208.9 & 183.8 \\ K—absorption edge (KeV) & 88.0 & 37.4 & 90.5 & 69.5 \\ Atomic number & 82 & 56 & 83 & 74 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Characteristic comparison of shielding materials. The density and volume of the materials used were calculated and the results are listed in Table 4. WO3 with a low porosity due to air removal showed a high tensile strength. When the porosity was higher than 20%, the strength dropped rapidly in the RSF using BaSO4. Figure 3 shows the results of the tensile strength of the RSF fabricated by increasing the amount of BaSO4 added from 250% to 350%, based on 100% silicone resin. As the porosity increased, the tensile strength gradually decreased. Therefore, the importance of air removal through defoaming in the blending process is highlighted. The result of the tensile strength test performed on the RSF, which was prepared by increasing the amount of BaSO4 added from 250% to 350% based on 100 units of silicone resin, is shown in Figure 3. The figure is an SEM image obtained by comparing the shielding materials of the RSF. It is a combination of tungsten and bismuth, which is widely used as an eco-friendly material. As shown in Figure 3, there is no significant difference in the appearance of the internal organization. However, a difference in size is shown in the composition of the particles. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Point**} & \multirow{2}{*}{**Shielding Film (0.6 mm)**} & **BaSO4** & **Bi2O3** & **WO3** \\ \cline{2-4}  & & **+ Silicon Resin** & \\ \hline
**Porosity (\%)** & **22** & 19 & 12 \\ \hline Tensile strength (MPa) & 6.4 & 9.2 & 10.5 \\ \hline \hline \end{tabular} BaSO4: barium sulfate, Bi2O3: bismuth trioxide, WO3: tungsten oxide powder.  
\end{table} 
Table 4: Porosity and tensile strength of shielding films. Figure 3: Particle size of shielded film by SEM. (**a**) Bismuth oxide (Bi2O3) and polyethylene compound; (**b**) tungsten oxide (WO3) and polyethylene compound. Figure 2: Radiation shielding films (RSF) viewed by SEM, comparing the mixing process with barium sulfate (BaSO4). (**a**) Mixing RSF without removing air; (**b**) mixing RSF with enough air removal. The indication is that the bonding state is maintained while the WO\({}_{3}\) maintains the size of micro units in the formulation of a polymer resin. As the pore size decreases, the porosity mostly tends to decrease, and as the porosity decreases, the shielding ratio improves. The shielding performance of the RSF manufactured for each shielding material was conducted using the experimental conditions proposed in this study.