Comprehensive property engineering of YGdAP:Ce scintillation crystals by optimizing the Y/Gd ratio

Abstract

Rare-earth aluminate perovskites have emerged as a promising class of scintillation crystals due to their high density and fast decay time. However, engineering their properties and growing bulk crystals with superior comprehensive performance for γ-ray detection remain a significant challenge. This paper employed a miniaturized Czochralski system to grow a series of continuous solid solution single crystals, Y_1−xGd_xAlO₃:0.5%Ce (x = 0, 0.25, 0.5, 0.75, 1), and studied their quality, optical, and scintillation properties. Our findings demonstrate that the Gd³⁺ concentration induces lattice distortion and cracking due to configurational entropy and local chemical stress, highlighting the need for optimizing growth conditions. Furthermore, the electronic structure analysis reveals that higher Gd³⁺ content reduces the bandgap and the rising edge of the Ce³⁺ 4f–5d₁ absorption transition, leading to a diminished light yield. Lastly, energy transfer between Gd³⁺ and Ce³⁺ evolves with Gd³⁺ concentration, resulting in faster decay times and changes in emission spectra, which offer valuable guidance for tailoring scintillation performance. This paper concludes that the comprehensive performance of YGdAP:Ce can be successfully optimized by elaborately adjusting the Y/Gd ratio. The tailored Y_0.5Gd_0.5AlO₃:0.5%Ce crystal features a high density (6.43 g cm⁻³), an extremely fast decay component (8.7 ns, 42.1%), and a relatively high light yield (12 000 ph MeV⁻¹). It integrates good scintillation performance, comparable to that of YAP:Ce, and high γ-ray detection efficiency. Moreover, the absence of expensive lutetium in YGdAP:Ce makes it a cost-effective alternative scintillator for γ-ray detectors.