Lu3+ Substituted Gd3Ga2Al3O12:Ce Ceramics for Improved X-Ray Imaging.

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.