Mass attenuation coefficients of B2O3–Al2O3–SiO2–CaF2 glass system at 0.662 and 1.25 MeV gamma energies

Dosimetric Study of Heat-Treated Calcium-Aluminum-Silicon Borate Dosimeter for Diagnostic Radiology Applications

The production of thermoluminescence (TL) dosimeters fabricated from B₂O₃-CaF₂-Al₂O₃-SiO₂ doped with Cu and Pr for use in diagnostic radiology is the main goal of this research. The TL samples were synthesized via the melt-quench technique processed by melting the mixture at 1200 °C for 1 h, and, after cooling, the sample thus created was divided into two samples and retreated by heating for 2 h (referred to as TLV30) and for 15 h (referred to as TLV17). SEM and EDS analyses were performed on the TL samples to confirm the preparation process and to investigate the effects of irradiation dosimetry on the TL samples. Furthermore, the TL samples were irradiated with γ-rays using a 450 Ci ¹³⁷Cs irradiator and variable X-ray beams (5-70 mGy). Two important diagnostic radiology applications were considered: CT (6-24 mGy) and mammography (2.72-10.8 mGy). Important dosimetric properties, such as the glow curves, reproducibility, dose-response linearity, energy dependence, minimum dose detectability and fading, were investigated for the synthetized samples (TLV17 and TLV30), the results of which were compared with the Harshaw TLD-100. The TLV17 dosimeter showed higher sensitivity than TLV30 in all applied irradiation procedures. The dose-response linearity coefficients of determination R² for TLV17 were higher than TLD-100 and TLV30 in some applications and were almost equal in others. The reproducibility results of TLV17, TLV30 and TLD-100 were less than 5%, which is acceptable. On the other hand, the results of the fading investigations showed that, in general, TLV17 showed less fading than TLV30. Both samples showed a significant decrease in this regard after the first day, and then the signal variation became essentially stable though with a slight decrease until the eighth day. Therefore, it is recommended to read the TL dosimeters after 24 h, as with TLD-100. The SEM images confirmed the existence of crystallization, whilst the EDS spectra confirmed the presence of the elements used for preparation. Furthermore, we noticed that TLV17 had grown dense crystals that were larger in size compared to those of TLV30, which explains the higher sensitivity in TLV17. Overall, despite the fading, TLV17 showed greater radiation sensitivity and dose-response linearity compared with TLD-100. The synthetized TL samples showed their suitability for use as dosimeters in diagnostic radiology radiation dosimetry.

Attenuation properties of radiation shielding materials such as granite and marble against γ-ray energies between 80 and 1350 keV

In this study, the γ-ray energy-dependent mass and linear attenuation coefficients of various granite and Turkish marble species have been experimentally obtained. Radionuclides (133Ba, 137Cs, 60Co and 22Na) with point geometry were used as γ-ray sources. The absorption capacity of each sample at nine γ-ray energies was measured using a high resolution γ-ray spectrometer equipped with a high purity germanium (HPGe) detector. To obtain the precision of the results (1σ standard deviation of the single value), this procedure was repeated six times for each species of granite and marble, respectively. The energy-dependent mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), the half (HVL) and the tenth value layer (TVL) were calculated following that the MAC and LAC results were compared to the literature values.