## 3 Result and Discussion
### Radiation Attenuation Studies
This is related to the PbO compound, which has a high density and cross-section of interaction. Hence, insertion of the PbO offers an additional resistance for passing photons, and the result is a significant reduction in the HVL values. In the low energy region in which the PE interaction is predominant, the HVL suffers a high increase with raising the photon energy. Increasing the energy of incident photons higher than 0.1 MeV causes a change in the interaction mode in which gamma-ray interacts with the glass atoms, where the PE decreases and CS begins to increase with raising the incident gamma photon energies. In this energy interval, the HVL increased linearly with energy. The HVL varies the range of 0.191-3.588, 0.171-3.397, 0.114-3.117, 0.054-2.717 cm with average HVL of 1.844, 1.739, 1.546, and 1.234 cm for glass samples SBT-Ti, SBT-Zn, SBT-Ba, SBT-Pb, respectively. The HVL continued its increase  
Figure 6: Variation of the mass attenuation coefficient versus the gamma-ray energy at different interaction regions. with the incident energy until 5 MeV, and then it began to reverse the trend and decreased slightly with raising the incident gamma photon energy. This decrease is due to the pair production, as illustrated in the mass attenuation coefficient section. The HVL in the mentioned interval varied between 5.768-5.543, 5.340-5.078, 4.579-4.223, 3.746-3.358 cm for samples SBT-Ti, SBT-Zn, SBT-Ba, SBT-Pb when the incident energy varied between 8 and 15 MeV, respectively. The fabricated glasses' thickness (\(\rm{D_{eq}}\)) equivalent to 1 cm of lead (Pb) was calculated at various energies, as presented in Figure 8. For all samples except the SBT-Pb, the \(\rm{D_{eq}}\) start very high at low energy. It takes values of 11.62, 8.81, 7.61, 4.56 cm for glasses SBT-Ti, SBT-Zn, SBTBa, and SBT-Pb, respectively. This high value of \(\rm{D_{eq}}\) is related to the high linear attenuation coefficient (LAC) of the Pb standard sample, where the LAC of the fabricated glasses is low compared to the LAC of Pb. After that, a sharp drop was achieved between 0.05 and 0.08 MeV. This reduction in the \(\rm{D_{eq}}\) for all samples is related to the K absorption edges of Te, which is the glass former in all studied glasses. In this energy interval between 0.05 and 0.08 MeV the \(\rm{D_{eq}}\) takes values of 4.14, 3.73, 2.49, and 2.57 cm for samples SBT-Ti, SBT-Zn, SBTBa, and SBT-Pb. Above 0.1 MeV, the \(\rm{D_{eq}}\) began to decrease gradually with increasing the incident gamma-ray energy. This is due to the CS interaction and increases in the LAC of fabricated glasses compared to Pb in this energy region. The lowest values of \(\rm{D_{eq}}\) achieved at gamma-ray energy, 1.5 MeV, take values 3.07, 2.90, 2.66, and 2.32 cm for the fabricated glasses SBT-Ti, SBT-Zn, SBTBa, and SBT-Pb. This illustrates that the fabricated glasses have a shielding capacity varied between 30 and 43% compared to the pure Pb at gamma-ray energy of 1.5 MeV. Above 1.5 MeV, the \(\rm{D_{eq}}\) began to increase slightly due to the  
Figure 7: Variation of the half-value layer (cm) versus the gamma-ray energy for the fabricated SBT glasses. small increase in the LAC of Pb compared to the fabricated glass samples. Also, Figure 8 illustrates that the high values of \(\rm{D_{eq}}\) obtained for glass samples SBT-Ti while the lowest achieved for the SBT-Pb. This is related to the amount of gamma-ray passing resistance offered by TiO\({}_{2}\) and PbO compounds, where the mentioned resistance for PbO is higher than that of TiO\({}_{2}\). Thus, the linear attenuation coefficient of the glasses containing PbO is higher than that of TiO\({}_{2}\) glasses, and the \(\rm{D_{eq}}\) for PbO doped glasses is lower than that of TiO\({}_{2}\) doped glasses. The transmission factor (TF, %) measures the photon numbers that can penetrate or escape from the shielding material. In contrast, the radiation protection efficiency (RPE, %) measures the number of photons that the shielding material can stop or absorb during the interaction.