# Itarare Group Sandstone as a Sustainable Alternative Material for Photon Radiation Shielding
## 4 Discussion
In the low-energy range, where photoelectric absorption is most pronounced, the number of photons that are completely absorbed or removed is maximized. Consequently, photons are absorbed quickly [49]. This results in EBF and EABF values being close to one, indicating minimal scattering and no buildup [50]. In contrast, in intermediate energy regions where incoherent scattering is more significant, photons continue to interact with the material after their initial interaction with it. This leads to higher accumulation factors [51]. Multiple incoherent scattering events occur, which increase the EBF and EABF values [47]. Moreover, accumulation factors are affected by the depth of photon penetration. The deeper a photon penetrates the material,the lower the likelihood of significant interaction, resulting in reduced accumulation factors [52]. Correlation analysis confirmed that chemical composition differences significantly influence the buildup behavior of the sandstone samples (Table 2). High negative correlations were observed between Fe\({}_{2}\)O\({}_{3}\) and EBF, as well as K\({}_{2}\)O and EBF. This indicates that samples with higher levels of these oxides, such as RMPS, tend to exhibit lower buildup values and, therefore, better shielding performance. Conversely, SiO\({}_{2}\) showed a positive correlation with EBF, supporting the observation that silica-rich samples, like AR2 and AR4, tend to have higher buildup factors. Regarding EABF, both TiO\({}_{2}\) and SO\({}_{3}\) demonstrated direct correlations with this parameter. This suggests that an increase in the amounts of these oxides corresponds to an increase in photon scattering. However, the small quantities of these oxides present in the samples, particularly in relation to SiO\({}_{2}\) and Al\({}_{2}\)O\({}_{3}\), mean that this finding should be approached with caution. Notably, EABF was not affected by variations in the iron oxide content of the sandstone samples studied. This suggests that air ionization is influenced more by the overall composition of the sample than by any single oxide in particular [53]. The previous literature supports our interpretations regarding EBF and EABF. Studies on basaltic rocks, such as those by [PERSON] et al. [53] and [PERSON] et al. [54], have shown variations in EBF and EABF that relate to the effective atomic number and interaction depth. Similarly, [PERSON] et al. [55] reported higher buildup values in granitioids with increased silica content, consistent with the trends observed in our study. [PERSON] et al. [50] emphasized the importance of iron-rich phases in enhancing photon attenuation, which leads to decreased buildup values--this aligns with our observations in samples like RMPS. The similarity in behavior among specific samples within the 0.1-1 MeV range, despite differing Fe\({}_{2}\)O\({}_{3}\) content (for example, RMPS versus AR1), may be attributed to compensating effects from other oxides, such as Al\({}_{2}\)O\({}_{3}\) and TiO\({}_{2}\), as well as structural factors not solely explained by chemical composition. In general, we observed that the heavier elements have a greater influence on the shielding parameters (MAC, LAC, MFP, HVL, and TVL), particularly at lower photon energies. The density of the sample was also a significant factor, particularly at lower photon energies. This result indicates that even slight differences in the chemical composition of the samples can significantly influence the shielding parameters. The Fe\({}_{2}\)O\({}_{3}\) content between the highest and lowest concentrations found in the sandstones was approximately 1.6 times. In the case of K\({}_{2}\)O, this difference was approximately 4.5 times, although the concentration of this oxide was significantly lower than that of the major ones. Thus, for the lowest photon energies (0.015 MeV and 0.1 MeV), the RMPS samples represent the material with the highest shielding capacity, while AR2 represents the lowest. At 1 MeV, the AR2 sample exhibited slightly superior attenuation performance compared to the other samples.