论文标题
探测器倾斜考虑在高能Bragg相干衍射成像中:一项仿真研究
Detector tilt considerations in high-energy Bragg coherent diffraction imaging: a simulation study
论文作者
论文摘要
本文解决了X射线布拉格相干衍射成像(BCDI)中的三维信号失真和图像重建问题,如果相对于衍射束的面积检测器的一般非正交取向,则解决了相干衍射成像(BCDI)。在第四代同步子源以新型BCDI适应的兴趣日益增加,需要在实验构型和随后的数据分析中即兴表演。本文中所设想的一种可能不可避免的即兴创作是一个光子计数区域检测器,在收购相干衍射信号期间,其脸从垂直于垂直于Bragg-diffracted Beam的倾斜倾斜。我们描述了一种可能需要这种检测器构型的情况,以及第三代同步基因的实验先例。在存在此类倾斜检测器的情况下,使用合成散射器的物理准确的衍射模拟,我们分析了观察到的信号变形的一般性质,并在图像重建过程中提供了校正其校正的处方。我们的模拟和重建是基于对BCDI采样几何学的已知理论以及最近开发的基于投影的波场传播方法的适应。这种构型修饰及其数值补救措施在实现非常规连贯的衍射测量几何形状方面具有潜在有价值,并最终为将BCDI整合到下一代光源的新材料表征实验中铺平了道路。
This paper addresses three-dimensional signal distortion and image reconstruction issues in x-ray Bragg coherent diffraction imaging (BCDI) in the event of a general non-orthogonal orientation of the area detector with respect to the diffracted beam. Growing interest in novel BCDI adaptations at fourth-generation synchrotron light sources has necessitated improvisations in the experimental configuration and the subsequent data analysis. One such possibly unavoidable improvisation that is envisioned in this paper is a photon-counting area detector whose face is tilted away from the perpendicular to the Bragg-diffracted beam during acquisition of the coherent diffraction signal. We describe a likely circumstance in which one would require such a detector configuration, along with experimental precedent at third generation synchrotrons. Using physically accurate diffraction simulations from synthetic scatterers in the presence of such tilted detectors, we analyze the general nature of the observed signal distortion qualitatively and quantitatively, and provide a prescription to correct for it during image reconstruction. Our simulations and reconstructions are based on an adaptation of the known theory of BCDI sampling geometry as well as recently developed projection-based methods of wavefield propagation. Such configurational modifications and their numerical remedies are potentially valuable in realizing unconventional coherent diffraction measurement geometries and eventually paving the way for the integration of BCDI into new materials characterization experiments at next-generation light sources.