## 11 Effect of BaO Modifier  
BaO when added to glass improves its density and stability [55]. Table 13 summarizes the mass attenuation coefficients of the studied glass with different fractions of BaO at a wide photon energy range from 10 keV to 20 MeV. On the other hand, Table 14 summarizes the neutron effective removal cross sections of the studied glass with different fractions of BaO. The photon-shielding capabilities of glass have been enhanced with the addition of the Sb\({}_{2}\)O\({}_{3}\) modifier while the neutron-shielding capabilities are decreased. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Photon Energy (keV)**} & \multirow{2}{*}{**Pure Glass**} & \multicolumn{6}{c}{**Glass with BaO Modifier**} \\ \cline{3-7}  & & **1\%** & **5\%** & **10\%** & **15\%** & **20\%** \\ \cline{2-7}  & & & **Mass Attenuation Coefficients (cm\({}^{2}\)/g)** & & & \\ \hline  
\hline \hline \end{tabular}
\end{table} 
Table 14: The neutron effective removal cross sections of the studied glass with BaO modifier. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Neutron Energy (keV)**} & \multirow{2}{*}{**Pure Glass**} & \multicolumn{6}{c}{**Glass with BaO Modifier**} \\ \cline{3-7}  & & **1\%** & **5\%** & **10\%** & **15\%** & **20\%** \\ \cline{2-7}  & & **1\%** & **5\%** & **10\%** & **15\%** & **20\%** \\ \hline
10 & 8.7100 & 8.6600 & 8.4639 & 8.2175 & 7.9726 & 7.7255 \\
20 & 30.9580 & 30.8940 & 30.1980 & 28.0520 & 26.9010 & 25.5530 \\
30 & 8.9307 & 8.8654 & 8.6071 & 8.2826 & 7.9564 & 7.6300 \\
40 & 8.9773 & 8.9070 & 8.6380 & 8.3013 & 7.9652 & 7.6280 \\
50 & 8.5718 & 8.5106 & 8.2516 & 7.9253 & 7.6011 & 7.2800 \\
60 & 9.1666 & 9.1030 & 8.8461 & 8.5251 & 8.2040 & 7.8825 \\
70 & 9.2569 & 9.2117 & 9.0336 & 8.8116 & 8.5871 & 8.3657 \\ \hline \hline \end{tabular}
\end{table} 
Table 13: The photon mass attenuation coefficients of the studied glass with BaO modifier. Comparison between the Influence of All Investigated Modifiers on the Shielding Properties of the Studied Glass  
In order to clearly compare the influence of the investigated modifiers on the performance of the studied glass as a radiation shield, the photon attenuation coefficients and the neutron removal cross sections were plotted for the pure glass against the glass with 1% fraction of the different modifiers studied in this work as shown in Figures 1 and 2. The glasses with 20% fraction of modifiers were compared and plotted as well in Figures 3 and 4. The average percentage differences between the coefficients and cross sections in the case of glass with modifiers are tabulated in Table 15 for easier comparison among the effects of the different modifiers. As can be seen from Figures 5 and 6, the results show that BaO enhances the photon-shielding properties of ZnO-Bi\({}_{2}\)O\({}_{3}\)-B\({}_{2}\)O\({}_{3}\)-SiO\({}_{2}\) the most among all compared metal oxides with an average between 0.95% and 18.94%, but on the other hand it decreases the neutron-shielding by an average ranging from \(-\)0.49% to \(-\)10.71%. The Sb\({}_{2}\)O\({}_{3}\) performed nearly the same with average percentage differences between 0.61% and 12.16% for photon-shielding abilities and between \(-\)0.61% and \(-\)8.74% for neutron-shielding abilities. The SrO also increased the ability of glass to shield against photons and reduced its ability against neutrons. The MgO modifier, on the one hand, enhanced the neuron-shielding capabilities of the studied glass the most with average percentage differences ranging from 0.56% to 10.43%, while it decreased the photon-shielding properties by, on average, between \(-\)0.39% to \(-\)7.89%. The Na\({}_{2}\)O, Al\({}_{2}\)O\({}_{3}\), and TiO\({}_{2}\) increased the ability of the studied glass to shield against neutrons as well and reduced the ability to shield against photons. In general, the effects of modifiers on photon shielding-properties are higher than on neutron-shielding properties.