STRUCTURED CSI(TL) SCINTILLATORS FOR X-RAY-IMAGING APPLICATIONS

We are developing developing large-area, thick, structured CsI(TI) ima ging sensors for a wide variety of X-ray imaging applications. Recentl y we have fabricated structured CsI(TI) scintillators ranging from 30 mu m (16 mg/cm(2)) to 2000 mu m (900 mg/cm(2)) in thickness and up to 15 x 15 cm(2) in area. Even 2000-mu m-thick film showed well-controlle d columnar growth throughout the film. Material characterization confi rmed that the film is crystalline in nature and that the stoichiometry is preserved. To improve the spatial resolution of thick films, post- deposition treatments were performed. The effect of these treatments o n film characteristics was quantitatively evaluated by measuring signa l output, modulation transfer function [MTF(f)], noise power spectrum [NPS(f)], and detective quantum efficiency [DQE(f)]. The data show tha t by proper film treatments, the film DQE(f) can be improved.