Development of x-ray scintillator functioning also as an analyser grating used in grating-based x-ray differential phase contrast imaging

• Published in: Chinese physics B Vol. 20; no. 4; pp. 222 - 227
• Main Author: 雷耀虎 刘鑫 郭金川 赵志刚 牛憨笨
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.04.2011
• Subjects: X射线; 分析仪; 扫描电子显微镜; 相衬成像; 闪烁功能
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/20/4/042901

In order to push the grating-based phase contrast imaging system to be used in hospitM and laboratories, this paper designs and develops a novel structure of x-ray scintillator functioning also as an analyser grating, which has been proposed for grating-based x-ray differential phase contrast imaging. According to this design, the scintillator should have a periodical structure in one dimension with the pitch equaling the period of self-image of the phase grating at the Talbot distance, where one half of the pitch is pixellated and is made of x-ray sensitive fluorescent material, such as CsI（T1）, and the remaining part of the pitch is made of x-ray insensitive material, such as silicon. To realize the design, a deep pore array with a high aspect ratio and specially designed grating pattern are successfully manufactured on 5 inch silicon wafer by the photo-assisted electrochemical etching method. The related other problems, such as oxidation-caused geometrical distortion, the filling of CsI（T1） into deep pores and the removal of inside bubbles, have been overcome. Its pixel size, depth and grating pitch are 3 p.m~7.5 ~m, 150 p~m and 3 Ixm, respectively. The microstructure of the scintillator has been examined microscopically and macroscopically by scanning electron microscope and x-ray resolution chart testing, respectively. The preliminary measurements have shown that the proposed scintillator, also functioning as an analyser grating, has been successfully designed and developed.