Structured CsI(Tl) scintillators for X-ray imaging applications

We are developing large-area, thick, structured CsI(Tl) imaging sensors for a wide variety of X-ray imaging applications. Recently we have fabricated structured CsI(Tl) scintillators ranging from 30 /spl mu/m (16 mg/cm/sup 2/) to 2000 /spl mu/m (900 mg/cm/sup 2/) in thickness and up to 15/spl times/15 cm/sup 2/ in area. Even 2000-/spl mu/m-thick film showed well-controlled columnar growth throughout the film. Material characterization confirmed 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 on film characteristics was quantitatively evaluated by measuring signal output, modulation transfer function [MTF(f)], noise power spectrum [NPS(f)], and detective quantum efficiency [DQE(f)]. The data show that by proper film treatments, the film DQE(f) can be improved.