Eu³⁺-doped Y₂O₃-based luminescent materials can be used as a scintillator for electron or high energy β-ray irradiation, which are essential for applications such as electron microscopy and nuclear batteries. Therefore, it is essential to understand their defect mechanisms and to develop materials with excellent properties. In this paper, Y₂O₃-based transparent ceramics with different Eu³⁺ doping concentrations were prepared by solid-state reactive vacuum sintering. This series of transparent ceramic samples exhibits strong red emission under electron beam excitation at the keV level. However, color change appears after the high-energy electron irradiation due to the capture of electrons by the traps in the Y₂O₃ lattice. Optical transmittance, laser-excited luminescence, X-ray photoelectron spectroscopy (XPS), and other analyses indicated that the traps, or the color change, mainly originate from the residual oxygen vacancies, which can be suppressed by high Eu doping. Seen from the cathodoluminescence (CL) spectra, higher doping concentrations of Eu³⁺ showed stronger resistance to electron irradiation damage, but also resulted in lower emissions due to concentration quenching. Therefore, 10% doping of Eu was selected in this work to keep the high emission intensity and strong radiation resistance both. This work helps to enhance the understanding of defect formation mechanisms in the Y₂O₃ matrix and will be of benefit for the modification of scintillation properties for functional materials systems.

Ce³⁺-activated Gd₃(Al,Ga)₅O₁₂:Ce scintillation ceramics have been widely studied due to their excellent scintillation properties. However, the relatively long radiative lifetime and slow decay components limit their applications in X-ray imaging. To address these issues, Lu³⁺ ions were introduced to partially substitute Gd³⁺ ions, thereby weakening the role of self-trapped states in the excitation process of Ce³⁺ and reducing the negative effects caused by shallow electron traps. As a result, the scintillation decay time was, overall, shortened, and an average decay time of 63 ns was obtained when x = 0.997. Meanwhile, the afterglow behavior induced by shallow electron traps was significantly suppressed (for the sample with x = 0.5, the afterglow intensity was measured to be approximately 0.48% of the initial intensity at 100 ms after the X-ray excitation was turned off). Meanwhile, an X-ray imaging spatial resolution comparable to that of commercial CsI:Tl (10 lp mm⁻¹) was achieved for the (Gd,Lu)₃Ga₂Al₃O₁₂:Ce³⁺ scintillation ceramics.