Chromium activated Ca₉Al (PO₄)₇ nanophosphors: synthesis, morphology and dosimetry characteristics

In this article, a sol-gel route was employed to prepare nanophosphor materials including Ca9-x CrxAl (PO4)(7) series (where 0.05 <= x <= 0.5 (mol%)). All subseries were irradiated to a gamma- test dose of 5 Gy and the thermoluminescence (TL) response of Cr-activated (0.1 mol%) Ca9Al (PO4)(7) sample has the best TL response and was chosen for investigations. The phase, particle size, surface morphology, and elemental mapping of the chosen sample Cr-0.1 in comparison with other ones (Cr-0.05 and Cr-0.5) were scrutinized using x-ray diffraction (XRD), transmission electron microscope (TEM), SEM-EDX mapping, and XPS techniques. XRD profiles showed that all diffraction peaks assigned to the trigonal R 3 c space group and the average of particle sizes obtained by the modified Scherer method and TEM data are closely related. The presence of Cr3+ ions in the Ca9Al (PO4)(7) lattice was assured by XPS spectra. Cr-0.1 chosen sample was studied after irradiation to different gamma-doses and displayed a prominent glow curve at 205 degrees C +/- 3.97 degrees C. It showed a linear dose-response curve from 200 mGy up to 10 Gy with fading of 24% upon 24 h and almost no significant signal loss for further interval times. The average Z(eff) value was similar to 11 at both 662 and 1250 keV energies making this sample a bone-equivalent material (11.3-11.8). Values of activation energies (eV) calculated by different methods were comparable. Results the dosimetric properties of that the Cr-0.1 sample can be surely considered as an additional recommended detector as other available ones in marketing.