Fabrication and imaging characterization of high sensitive CsI(Tl) and Gd2O2S(Tb) scintillator screens for X-ray imaging detectors

Abstract

Indirect-detection methods consisted of an X-ray converter and photodiode arrays are more widely used in medical diagnosis and industrial fields. Two major scintillation materials such as terbium-doped gadolinium oxysulfide(Gd2O2S:Tb. Gadox) and thallium-doped cesium iodide(CsI:Tl) are commonly used. In this work, Gadox screens were manufactured by particle in binder (PIB) layer method and CsI:Tl scintillator films with columnar structure were also fabricated by thermal evaporation method onto glass substrates. Furthermore, two sample screens were coated to increase the light collection efficiency by white TiO2 reflective layers. The scintillation properties, such as emission spectrum and light output of these materials were measured by X-ray luminescence condition. In order to investigate the imaging performance of both Gadox and CsI:Tl scintillation screens as converters of X-ray imaging detectors, these materials were optically coupled with a 2D CCD image sensor. The light response to X-ray dose, spatial resolution and X-ray images were measured and analyzed under X-ray imaging system condition. (C) 2009 Elsevier Ltd. All rights reserved.