基于CCD和CsI闪烁体的硬X射线成像

根据CCD的工作特点,采用曝光控制和多帧图像叠合技术,研制了基于CCD和CsI闪烁体的硬X射线成像探测器,以提高对硬X射线的探测效率。搭建了实验平台,以微加工技术制作的镍准直器为成像目标进行了实验验证。实验中,利用55Fe放射源对CCD进行直接成像;然后利用241 Am放射源同时对CCD和硬X射线成像探测器分别进行直接成像和间接成像。最后,对图像中出现的拖影、清晰度渐变和区域亮度不同等现象进行分析。分析结果表明:相比CCD本身,这种技术不仅拓展了探测器的可响应能区,而且提高了的量子效率,并且在241 Am放射源照射下,实现了对硬X射线的高分辨成像,其空间分辨优于50μm。该器件可作为位置灵敏探测器应用于未来空间天文观测。

Hard X-ray imaging based on CCD and CsI scintillator

In consideration of the working characteristics of a Charge Coupled Devices (CCD ) , an imaging detector based on CCD and CsI scintillator was presented by using flexible exposure control and multi-frame superpositioning techniques to improve the detection efficiency of hard X-ray .An experimental platform was built ,in which a nickel collimator based on a micromachining techniques was adopted as the imaging spatial target .In the experiment ,the 55 Fe X-ray source was adopted for direct imaging of CCD itself .Then ,the 241 Am X-ray source was used for both direct imaging by CCD itself and indirect imaging by the hard X-ray imaging detector .Finally ,some phenomenon exhibited in the images such as drag shadows ,clarity gradients ,and different area brightness were analyzed .The results indicate that the techniques presented not only expands the responsive energy range ,but also improves the quantum efficiency significantly as comparing with CCD itself . In addition , under exposure with 241 Am X-ray sources ,hard X-ray imaging with a spatial resolution better than 50 μm was achieved .The imaging detector is promising to be a position sensitive detector for future space astronomical observations .