## 3 Results and Discussion
From the results in Table 3, there was a slight difference among the libraries particularly in the 20 keV photon energy. This is because the glasses have some amount of molybdenum, and the K-edge energy of molybdenum lies near the 20 keV photon energy. This phenomenon is explained by Figure 3 which describes the photoelectric cross section of each library for the molybdenum element. The values for the K-edge of molybdenum, in each library, are 19.965 keV in EPDL97, 20.00 keV in XCOM-NIST, and 20.006 keV in EPICS2017. For both XCOM and EPDL97, the 20 keV energy appears after the Mo K-edge. Therefore, there is a higher value for MAC of the glasses at 20 keV using XCOM and EPDL97. This is the opposite for EPICS2017 since the Mo K-edge in this library is slightly higher than 20 keV. This results in lower MAC value at 20 keV for EPICS2017. Another slight difference among the libraries was found in the 80 keV photon energy MAC results. In this energy, the XCOM-NIST had a slight discrepancy with EPICS2017 and EPDL97, because the 80 keV energy is near the K-edge of Pb (\(\sim\)88 keV). It has been shown previously that MACs or cross sections vary among the libraries, especially in the photon energies near X-ray edges [24; 29]. Aside from these slight differences, there was a good agreement found among all three libraries for the rest of the photon energies. Figure 4 shows the MAC for the five Pb-SX glasses at four energies (20, 40, 60 and 80 keV). The data exhibited in this figure reveals that the MAC at 20 keV is much higher than the MAC at 40, 60 and 80 keV. This is correct for the five Pb-SX glasses. This high value of MAC at 20 keV in comparison with the other energies can be directly related to the photoelectric interaction, in which the probability of this interaction is high at 20 keV and reduces with increasing energy. So, increasing the energy from 20 to 80 keV causes the MAC to drop. These results agree with the observation of [PERSON] and [PERSON] where they observed that the MAC of the glasses is very high at 140 keV and the values reduce for the energy of 364 and 511 keV [43]. Additionally, we can observe from Figure 4 that the MAC for Pb-SX glasses improves with the addition of PbO; Pb-S1 had the lower MAC, while Pb-S5 had the highest MAC. The MAC increases from 52.79 to 63.18 cm\({}^{2}\)/g at 20 keV on increasing the PbO from 30 to 50 mol %. Additionally, at 40 keV, the MAC increases from 8.81 cm\({}^{2}\)/g (for Pb-S1) to 10.53 cm\({}^{2}\)/g (for Pb-S5), while at 80 keV, the MAC for Pb-S1 and Pb-S5 are 1.52 and 1.79 cm\({}^{2}\)/g, respectively. From these values, we can conclude that \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{Pb-S1} & \multicolumn{3}{c}{Pb-S2} & \multicolumn{3}{c}{Pb-S3} \\ \cline{2-10}
**Energy** & **EPICS2017,** & **EPDL97,** & **Phy-** & **EPICS2017,** & **EPDL97,** & **Phy-** & **EPICS2017,** & **EPDL97,** & **EPDL97,** & **Phy-** \\
**(keV)** & **(EpIXS)** & **(EpIXS)** & **X/PSD** & **ENDF/B-VIII** & **ENDF/B-VIII** & **ENDF/B-VIII** & **ENDF/B-VIII** & **ENDF/B-VIII** & **ENDF/B-VIII** & **ENDF/B-VIII** & **ENDF/B-VIII** \\ \hline
20 & 49.703 & 52.619 & 52.799 & 53.155 & 55.827 & 56.025 & 56.089 & 58.554 & 58.767 \\
40 & 8.808 & 8.791 & 8.811 & 9.340 & 9.323 & 9.344 & 9.792 & 9.774 & 9.797 \\
60 & 3.085 & 3.084 & 3.107 & 3.267 & 3.266 & 3.291 & 3.421 & 3.421 & 3.447 \\
80 & 1.486 & 1.494 & 1.522 & 1.570 & 1.578 & 1.608 & 1.641 & 1.650 & 1.682 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: MAC (cm\({}^{2}\)/g) of the samples. the increment of MAC at 20 keV as the concentration of PbO increases is higher than that at 40, 60 and 80 keV. It is important to remember that when the LAC values of the medium increases, its potency to attenuate the radiation also increases. In Figure 5 we exhibited the LAC for the five Pb-SX samples at the four tested energies. Glass codes Pb-S5 showed the highest LAC. This is due to the higher concentration of PbO in this glass (50 mol %).