## 2 Materials and Methods  
The shielding material used in this study was tungsten, which has an atomic number of 74, an atomic weight of 183.84 g/mol, and a density of 19.25 g/cm\({}^{3}\). As its shielding performance is close to that of lead, it has been widely used recently as an eco-friendly radiation shielding material [14]. In this study, pure tungsten shielding fiber was produced from tungsten yarn made with industrial filament tungsten wire with a diameter of 30 \(\pm\) 0.05 \(\upmu\)m. The fabric was manufactured using a weaving machine ([PERSON], Dornier, HTVS 8/S20, Friedrichshafen, Germany). The diameter of the tungsten wire was selected such that it was small enough to maintain the flexibility of the tungsten fabric and provide a high weaving density, but not too small that the yarn could break during the weaving process. Therefore, a diameter of 30 \(\upmu\)m was selected in this study [15]. In addition, the fabric was woven by the twil weave method to minimize the spacing between the yarns, which occurs in warp and weft yarns from the plain weave method traditionally used for weaving [16]. Figure 1 shows the technical difference between the twil weave method and the plain weave method. Warp and weft yarns are crossed one by one in the plain weave method, whereas two or more yarns are crossed in the twil weave method [17]. In previous studies, mesh-type connection or knit weaving methods were suggested [18]. However, maintaining a constant shape during processing and achieving reproducibility of the shielding performance requires a more effective weaving method. In addition, the fabric was intended to be stacked for shielding applications involving higher radiation intensities. Therefore, in this study, the fabric was fabricated with high density using the twil weave method. The reproducibility of the shielding performance depends on the thickness of the shield and the consistency of the process technology. Figure 2 presents a fabric woven using tungsten yarn and Figure 3 presents the fabric weaving process with a weaving machine. Methods for improving the shielding performance of the woven shielding fiber include a laminated structure, that is, using multiple layers of overlapping fabric, and a double coating method [19; 20]. In general, a laminated structure of shielding fibers has the disadvantage of increased shielding thickness. Therefore, in this study, a method was developed in which a polyethylene (PE) yarn was wound around a tungsten wire and then woven into a fabric, and tungsten nanopowder was dispersed in the woven shielding fabric. Even with high-density weaving, gaps and voids between the yarns reduce the shielding performance of the tungsten shielding fiber. Therefore, filling the voids with tungsten  
Figure 1: Fabric weaving methods. **(a)** Plain weave method, **(b)** Twill weave method. Figure 3: High-density weaving process of shielding fiber. Figure 2: Tungsten yarn and fabric. nanoparticles was expected to improve the shielding performance of the fabric. The air pressure dispersion method of dispersing the tungsten nanoparticles on the shielding fiber fabric was configured as shown in Figure 4[21]. The air pressure dispersion method disperses tungsten nanoparticles onto the fabric through a thin air nozzle with a diameter of 1.5 mm. In this study, a direct-dispersion form was applied. A trace amount of thermocetting phenolic resin adhesive was used for the complete fixation of tungsten powder particles on the shielding fabric, thus, fixing the particles well, increasing the affinity with the fibers, and filling the voids. The dispersed tungsten powder was applied in a small amount of less than 8 wt% of the total shielding fiber. In this experiment, to determine the shielding area for medical radiation, the range and energy of the scattered rays inside the imaging room, which is the diagnostic area, were presented, and the shielding performance of direct radiation was evaluated.