Thermoluminescence properties of dysprosium-doped calcium borate glass for dose measurement subjected to ionizing radiation

摘要

Thermoluminescene (TL) dosimeters are widely used in radiation therapy to verify the radiation dose received by cancer patients. This research was carried out to study the TL properties of Dysprosium (Dy) doped borate glass as a TL dosimeter subjected to photon and electron irradiations. The glass samples with various Dy concentrations were prepared by melt-quenching technique. X-Ray diffraction analysis indicates that the glasses are amorphous. The performance of the glass samples were compared to the TLD-100 in terms of TL response, linearity, sensitivity, dose response, fading and reproducibility. The addition of Dy2O3 in borate glass enhanced TL sensitivity and improved the TL intensity of the glass. It was found that calcium borate with Dy concentration of 0.30 mol% was the optimum concentration to produce the highest TL response. The TL intensity increased with Dy concentration up to 0.40 mol% before it begin to gradually decrease. This phenomenon is due to the concentration quenching. The TL properties were studied over the useful radiotherapeutic dose in the range of 0.5 Gy to 4 Gy when subjected to 6 and 10 MV photon and 6 and 12 MeV electron irradiation. The sensitivity of Dy doped calcium borate was 5.8 times more sensitive than that of undoped sample and 6.8 times less sensitive compared to TLD-100. A correlation coefficient of 0.98 was obtained for reproducibility and the minimum fading for this glass was 10% for 60 days observation. By using XCOM software, the Zeff of the glass was found to be 12.14 and 13.60 for undoped and Dy doped glass, respectively.