Abstract
The scintillation and energy-storage properties of YAlO3 (YAP) crystals doped with Sc3+ and La3+ isoelectronic dopants were investigated in this work. The YAP:Sc and YAP:La crystals were grown from the melt with a nominal Sc and La content in the 0.2–5.0 mol.% range using the novel micro-pulling-down method. We found that the segregation coefficient of Sc ions in YAP:Sc (0.2–1.0 mol.%) crystals is about of 0.35–0.4 and decreases to around 0.2 at Sc content of 5.0 mol.% when the segregation coefficient of La ions in YAP:La (1.0–5.0 mol.%) crystals is 0.008–0.01. The scintillation and stimulated luminescence phenomena, like thermo- and photoluminescence, were utilized for the property characterization of the studied materials. The cathodoluminescence and X-ray-excited luminescence were used for the imitation of scintillation in the YAP:Sc and YAP:La crystals. The influence of Sc3+ and La3+ dopant concentration on the CL and RL emission spectra, as well as the shape of the measured thermoluminescence (TL) glow-curves, was also investigated. The measured emission spectra showed dominant emission of Sc3+ and La3+ ions in the UV range. For this reason, the YAP:Sc and YAP:La crystals can be considered for creation of ultraviolet (UV)-emitting scintillators. For the undoped YAlO3 crystals, the main TL emission peak occurs in a low-temperature range at 375 K. Meanwhile, even a small addition of dopants causes a strong suppression of luminescence of the YAP host and high-temperature peaks become dominant in the TL glow-curves of YAP:Sc and YAP:La crystals. Moreover, the amplitude of emission does not change monotonically with increasing dopant content. The kinetic parameters of emission were also evaluated, and the first-order behavior was confirmed in all cases. The dosimetric properties of investigated materials such as dose response, fading rate, and the lowest measurable dose are also discussed. The obtained results tend to suggest that the YAlO3 perovskite host, apart from its application for the development of efficient scintillators, may also be considered as a promising matrix for the creation of energy-storage phosphors for dosimetric applications.
Highlights
The micro-imaging technique utilizing X-ray sources for applications in biology, medicine, or industry needs the creation of efficient scintillation screens for micro-tomography image detectors with a spatial resolution in the μm range
During the last few years, new scintillation materials based on mixed oxide crystals of perovskite and garnet structure doped with rare-earth ions were developed for such a purpose
Taking into account that the spatial resolution of scintillating screens is primordial to the energy of their luminescence, the latter implies that the application of UV-emitting Sc3+ - and La3+ -doped scintillation materials to the micro-imaging technique can improve the spatial resolution of the detector
Summary
The micro-imaging technique utilizing X-ray sources for applications in biology, medicine, or industry needs the creation of efficient scintillation screens for micro-tomography image detectors with a spatial resolution in the μm range. During the last few years, new scintillation materials based on mixed oxide crystals of perovskite and garnet structure doped with rare-earth ions were developed for such a purpose. These materials showed advantageous properties as superior light yield (LY). Taking into account that the spatial resolution of scintillating screens is primordial to the energy of their luminescence, the latter implies that the application of UV-emitting Sc3+ - and La3+ -doped scintillation materials to the micro-imaging technique can improve the spatial resolution of the detector
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