The Role of Different Luminescence Centers On the Dose Response of Al2O3:C OSLDs: A Systematic Investigation Using Continuous Wave and Pulsed OSL Readouts
D Flint*, D Granville, G Sawakuchi, Carleton University, Ottawa, ONSU-E-T-67 Sunday 3:00:00 PM - 6:00:00 PM Room: Exhibit Hall
Purpose: To characterize the dose response of optically stimulated luminescence (OSL) from Al2O3:C detectors (OSLDs) using continuous wave (CWOSL) and pulsed (POSL) stimulations and different detection windows.
Methods: Al2O3:C OSLDs were irradiated for a dose range from 0.1 to 200 Gy using a Co-60 source. Readouts of OSLDs were performed with a custom-made OSL readout system using CWOSL and POSL stimulations. Two separate optical filter sets (Hoya U-340 and Kopp 5113 optical filters) were employed to filter out the 530 nm stimulation light from the OSL signal and selectively separate the blue and ultraviolet OSL emissions of Al2O3:C OSLDs. The OSL decay curves were then analyzed using a range of intervals of integration to define the OSL signal, i.e., initial intensity or total area under the OSL decay curves. The results from CWOSL and POSL with different filter sets were compared to determine the contributions of the different recombination centers to the net OSL signal ofAl2O3:C OSLDs.
Results: The blue emission had a larger linearity range (up to ~2 Gy) than the ultraviolet emission (up to ~1 Gy). At 10 Gy, the dose response of the blue emission deviated from linearity by about 13% while the ultraviolet emission deviated by about 60%.
Conclusions: The dose response of Al2O3:C OSLDs depended on the detection window used to acquire the OSL signal. The ultraviolet emission had much higher supralinearity than the blue emission in the dose response of Al2O3:C OSLDs. A higher range of linearity can be achieved by selective detection of the blue emission, which can be performed using optical filters or POSL. The results of this work may assist in the development of: i) new commercial OSL readers; and ii) dosimetry protocols on the use of OSLDs in clinical settings.