X 射线双正弦相位光栅干涉仪的条纹可见度研究

X射线双相位光栅干涉仪在使用矩形光栅时,获得的条纹可见度较低,导致暗场图像信噪比严重降低,因此有必要探索提高条纹可见度的潜在途径。文章开展双正弦相位光栅干涉仪的条纹可见度研究,并对比了双正弦相位光栅干涉仪与双矩形相位光栅干涉仪在典型实验参数下的条纹可见度随光栅间距的变化规律。计算结果表明,双正弦相位光栅干涉仪在大光栅周期、大光源焦点尺寸和大探测器像素尺寸下具有优势,且条纹可见度峰值对应的光栅间距更小,使系统更紧凑。文章研究结果可为X射线双相位光栅干涉仪的参数设计与性能优化提供理论指导。

When binary gratings are used in X-ray dual-phase grating interferometers, the fringe visibility is relatively low, resulting in a serious reduction of the signal-to-noise ratio of dark-field images. Therefore, it is necessary to explore potential ways to improve the fringe visibility. In this paper, a study based on dual-sinusoidal phase grating interferometer is presented, and fringe visibility as a function of grating spacing between the dual-sinusoidal and dual-binary phase grating interferometers is compared under different experimental parameters. The results show that the dual-sinusoidal phase grating interferometer has certain advantages in large grating period, large light source focus size and large detector pixel size, and the grating spacing corresponding to the fringe visibility peak is smaller, which makes the system more compact. The results of this paper can provide theoretical guidance for parameter design and performance optimization of X-ray dual-phase grating interferometers.