Magnesium aluminate spinel for optically stimulated luminescence dosimetry

Motivated by the search of new materials for optically stimulated luminescence (OSL) dosimeters, magnesium aluminum spinels with different Mg:Al ratios were investigated. Powders were prepared via the co-precipitation method with Mg:Al ratios 1:2 (stoichiometric), 1.5:2 (MgO-rich) and 1:3 (Al2O3-rich) and calcined at 1000 degrees C in air for 2 h. A higher level of structural disorder was found in the powders than in the single crystal as determined by X-ray diffraction and Raman spectroscopy measurements, while the same luminescence centers were present in all materials as shown by X-ray induced radioluminescence measurements. Among the different Mg:Al ratios, stoichiometric spinel presented superior OSL dose response, being linear within 0.16 Gy and 2 Gy, presenting 1% reproducibility of the dosimetric response after repeated exposure to the same dose, having the least fading, and with a minimum detectable absorbed dose (MDD) of 0.65 mGy. (C) 2021 Elsevier B.V. All rights reserved.