Study of dosimetric properties of Al2O3:C,Mg as radiophotoluminescent detectors

The objective of this work was to characterize the dosimetric properties of the Al2O3:C,Mg powder- based RPL detectors in the range of doses of interest in radiation therapy. The characterization of the dosimetric properties of Al2O3:C,Mg in dose ranges up to 60 Gy has been done. Two types of samples are prepared and tested a) Mixtures of powder with polycaprolactone and b) coatings of powder on polyurethane on polycaprolactone substrate. Properties such as linearity of RPL signal vs. dose, sensitivity of the dosimetry system such as RPL detector, PMT, LED wavelength and intensity, configuration of optical filters and setup, reproducibility of the measurements, zero dose signal (background level) etc. has been studied. It has been found that the material properties are in good agreement with properties required for a dosimeter in medical applications. The linearity of RPL signal vs. dose curve for 5% (5% Al2O3:C,Mg powder of the weight of polymer) and 10% samples has been plotted. The results obtained show that RPL detector has a linear response of RPL signal vs. dose below 20 Gy. The optimized conditions has been obtained for reading setup like the intensity of the stimulation light, optical filters and setting the detection window etc. The reproducibility tests have been done on different days and good results has been observed for the reproducibility at different days. RPL signal for the background has been measured.