Quasi-pixel structured nanocrystalline Gd2O3(Eu) scintillation screens and imaging performance for indirect X-ray imaging sensors

Abstract

A novel quasi-pixel structured scintillation screen with nanocrystalline Gd2O3:Eu particle sizes was introduced for indirect X-ray imaging sensors with high sensitivity and high spatial, resolution. A nanocrystalline Gd2O3:Eu scintillating phosphor with average 100 nm sizes was used as a conversion material for incident X-rays into optical photons. In this work, silicon-based pixel structures with different 100 and 50 mu m pixel sizes, 10 mu m wall width and 120 mu m thickness were fabricated by a standard photolithography and deep reactive ion etching (DRIE) process. The pixelated scintillation screen was fabricated by filling the synthesized nanocrystalline Gd2O3:Eu scintillating phosphor into pixel-structured silicon arrays, and X-ray imaging performance such as relative light intensity. X-ray to light response and spatial resolution in terms of modulation transfer function (MTF) of the fabricated samples were measured. Although high spatial resolution imaging was largely achieved by pixel-structured nanocrystalline Gd2O3:Eu scintillation screens, X-ray sensitivity was still low for medical imaging applications. As a result, novel quasi-pixel structured screens with additional thin Gd2O2S:Tb scintillating layer were proposed for X-ray imaging detector with suitable sensitivity and spatial resolution in comparison with pixel-structured screens, and X-ray imaging performance of quasi-pixel structured nanocrystalline Gd2O3:Eu scintillating screens was investigated. (c) 2011 Elsevier B.V. All rights reserved.