四通道球面弯晶成像系统设计及实验研究

Design and experimental research of four-channel spherically bent crystal imaging system

基于动态X射线荧光成像技术对高集光效率、单色化成像诊断设备的需求,提出了一种四通道球面弯晶成像系统设计。采用"圆锥体"空间排布方式,解决了多个通道耦合问题。通过调整弯晶姿态,实现了像点的合理分布。针对4.51keV能点,采用Ge(400)球面弯晶作为成像元件,给出了四通道弯晶成像系统的光学初始结构参数。在实验中利用Ti靶X射线光管,对单个通道进行了网格背光成像,获得的二维图像放大倍数为7.8倍,空间分辨率达到15μm,初步验证了系统的成像性能。四通道弯晶成像系统与分幅相机结合,能有效解决动态X射线荧光成像技术信号弱、图像信噪比低的技术难点。

Since dynamic X-ray fluorescence imaging technology requires diagnostic equipment which has high throughput and narrow spectral width,we present the design of four-channel spherically bent crystal imaging system.The system adopts a cone spatial configuration to solve the problem of multiple channel coupling.With the size limit of framing camera taken into account,the images are reasonably planned by adjusting the position of bent crystal.We utilize Ge 400 crystal as the imaging component at 4.51 keV and then propose optical initial structural parameters of system.Grid backlit images of single channel are obtained by using X-ray tube in the laboratory.The magnification is 7.8,and the spatial resolution is 15 μm.The results preliminarily verify the performance of system.The four-channel system combined with the framing camera can effectively solve the technical difficulties such as weak signal and low signal to noise ratio in dynamic fluorescence imaging.