Ta ₂ O ₅ as a Novel Additive for Highly Transparent Lu ₂ O ₃

ABSTRACT

Highly transparent Lu ₂ O ₃ :Eu scintillation ceramics were fabricated by pressureless sintering with Ta ₂ O ₅ as a novel sintering additive. The optical transmittance, microstructural evolution, and photoluminescence and scintillation properties of the samples were investigated. Ta ₂ O ₅ doping generates interstitial oxygen ions, which, on one hand, effectively suppress grain growth and promote densification, leading to high optical transparency. The maximum linear transmittance reaches 78.7% and 80.3% at 611 and 1100 nm (1 mm in thickness), respectively, when the sample doped with 0.3 at% Ta ₂ O ₅ sintered at 1840°C. On the other hand, these defects exert a detrimental effect on the luminescent and scintillation properties of the samples. Both intensities exhibit a non‐monotonic dependence on Ta ₂ O ₅ concentration, yet all samples display characteristic red emission of Eu ³⁺ centered at ∼611 nm. Notably, the XEL intensity of all ceramics surpasses that of BGO single crystals, demonstrating excellent scintillation performance. The samples also exhibit superior dose‐rate linearity ( R ²  = 0.9548) with a low detection limit of 0.113 mGy·s ⁻¹ . Furthermore, negative thermal quenching behavior is observed, which is ascribed to the thermally stimulated release of carriers from defect states.