双三角形相位光栅X射线干涉仪的条纹可见度  

Fringe visibility in X-ray interferometer using dual triangular phase gratings

作　　者：陈子涵 宋梦齐 陈恒 王志立[1] Chen Zi-Han;Song Meng-Qi;Chen Heng;Wang Zhi-Li(School of Physics,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]合肥工业大学物理学院,合肥230009

出　　处：《物理学报》2023年第14期305-315,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11475170,U1532113,11905041);中央高校基本科研业务费(批准号:JZ2022HGTB0244);安徽省自然科学基金(批准号:2208085MA18)资助的课题。

摘　　要：X射线光栅干涉仪成像需要高条纹可见度以获得高信噪比图像.最近的报道证实,X射线双矩形相位光栅干涉仪实验测量的条纹可见度较低.为此,提出了基于双三角形相位光栅X射线干涉仪的条纹可见度研究.利用X射线双相位光栅干涉仪的强度变化规律,对比研究了单色照明和不同多色照明下,双三角形相位光栅X射线干涉仪与双矩形相位光栅干涉仪的条纹可见度随光栅间距的变化规律.结果表明:无论是单色照明还是多色照明,双三角形相位光栅X射线干涉仪的条纹可见度的峰值随相移量的增加而增大.当相移量为5π/2时,双三角形相位光栅X射线干涉仪的条纹可见度在单色照明下比双矩形相位光栅干涉仪的条纹可见度提高约21%,在多色照明下提高至少23%.而在多色照明下,随着X射线平均能量偏离光栅设计能量的增加或光源焦点尺寸的增加,双相位光栅干涉仪条纹可见度的峰值均会单调下降.这些结果可作为X射线双相位光栅干涉仪的参数设计和性能优化的理论指导.In recent years,the X-ray interferometer using dual phase gratings has been extensively studied.The large periodic fringes produced by the X-ray interferometer using dual phase gratings can be directly detected by ordinary detectors.At the same time,the X-ray interferometer using dual phase gratings can reduce the radiation dose of the sample without using absorption gratings.Meanwhile,a high fringe visibility is always preferred to achieve a high signal-to-noise ratio for X-ray grating interferometry.However,recent studies have reported that experimental fringe visibility in X-ray interferometer using dual rectangular phase gratings is relatively low.Therefore,it is necessary to further increase the fringe visibility in X-ray interferometry using dual phase gratings.This work focuses on the analysis of fringe visibility in X-ray interferometer using dual triangular phase gratings.Based on the fringe intensity distribution formula of X-ray dual phase grating interferometer,the fringe visibility of the dual triangular phase grating interferometer is investigated as a function of the grating spacing under monochromatic and polychromatic illumination,respectively.For comparison,the fringe visibility of the dual rectangular phase grating interferometer is also studied under the same condition.The results show that the maximum fringe visibility of the dual triangular phase grating interferometer increases with the phase shift increasing regardless of monochromatic or polychromatic illumination.Under monochromatic illumination,the maximum fringe visibility of dual 5π/2 triangular phase gratings is about 21%higher than that of dual rectangular phase gratings.Under polychromatic illumination,the fringe visibility of dual 5π/2 triangular phase gratings is at least 23%higher than that of dual rectangular phase gratings.Under polychromatic illumination,the greater the deviation of X-ray average energy from the grating design energy,the greater the decrease of maximum fringe visibility of the dual phase grating interferome

关 键 词：X射线成像 光栅干涉仪 三角形相位光栅 条纹可见度 

分 类 号：TH744.3[机械工程—光学工程]