Optimizing gamma-ray shielding for boron neutron capture therapy by using unglazed ceramic composites

In this study, the researchers investigated the effectiveness of different ceramic samples in filtering gamma rays emitted by various sources. The samples, which contained varying concentrations of lead and barium, were evaluated for their potential use in beam-shaping assembly systems for Boron Neutron Capture Therapy techniques, specifically those using the ²⁵²Cf neutron source for cancer treatment. Stilbene and NaI (Tl) were used to measure the total and pure gamma rays in this study. In addition, theoretical calculations using the Phy-X/PSD software have been conducted across a broad energy range, spanning from 0.001 to 18 MeV. These calculations aim to determine the attenuation of gamma rays and the relative deviations compared to the corresponding measured gamma-ray energies. Various composites with different percentages of additives and thicknesses, ranging from 0.8 cm to 4 cm, have shown satisfactory attenuation properties for gamma-ray shielding applications. However, the samples containing lead, especially the unglazed ceramic composites with 15 % lead and 4 cm thickness, were found to have the most preferred attenuation properties. The results obtained indicate that samples with a higher lead content are more effective attenuators compared to those with additional barium. In addition, the relationship between the transmission gamma ray factor and the percentage of additives and energies of gamma rays can be determined from the experimental linear attenuation coefficient coefficients. In addition, various coefficients such as the mass attenuation coefficient, half-value layer, effective atomic numbers, and effective electron densities are studied theoretically for the unglazed ceramic samples. The dose rate is also taken into consideration.