Scintillating Glass‐ceramic Substrates for Indirect Flat Panel Detectors in Digital Radiography

Indirect flat panel detectors (I-FPDs) enable digital radiography at high X-ray energies. However, the performance of these devices is limited due to the large number of X rays that pass through them undetected. The authors hypothesize that a glass-based scintillator may serve as a substrate for the thin film transistors and photodiodes in an I-FPD, leading to improvements in X-ray detection for improved performance. The authors synthesized a series of five glass-ceramic scintillators based on an oxyhalide glass matrix. Each glass ceramic contains barium chloride crystals which serve as scattering centers to prevent "light trapping" in the material; barium chloride is also a well-known scintillation crystal. Four of the samples contain trivalent terbium, which serves as a second luminescent center. The light output of each sample was compared against a well-known X-ray scintillator, gadolinium oxysulfide (GOS) under RQA9 exposure conditions, in the back-irradiation configuration. The addition of terbium oxide to the glass composition increases the detected light output, which varies by concentration. The thickness of the glass-ceramic scintillator has a profound effect on performance, with the results influenced by such factors as self-attenuation of emission in the thicker samples and decreased X-ray capture in the thinner samples. The brightest sample tested achieved a light output 13% that of the GOS intensifier screen. The results indicate that the use of scintillating glass-ceramic substrates should lead to increased performance in indirect digital radiography.