标题： 高能X射线下的Bragg相干衍射成像相位检索 显示英文标题

标题： Phase retrieval for Bragg coherent diffraction imaging at high X-ray energies

摘要： 具有能量$\geq 50$ keV 的相干 X 射线束有可能通过布拉格相干衍射成像（BCDI）实现对块状多晶材料中单个晶体内的原子晶格畸变场的三维成像。 然而，由于在高能 X 射线下傅里叶空间压缩导致的衍射信号欠采样，传统的相位检索算法不适合三维重建。 为了解决这个问题，我们利用一种带有傅里叶约束的相位检索方法，该方法专门针对使用粗间距探测器像素测量的欠采样衍射数据，这些像素对底层信号进行分箱处理。 通过我们的方法，我们表明可以在不物理上对衍射信号进行插值的情况下，从受像素面积积分影响的欠采样布拉格衍射数据集中重建出三维应变晶体。 通过模拟和实验结果，我们证明在相位检索过程中显式建模傅里叶空间压缩提供了一种可行的方法来反转高能 BCDI 数据，否则这些数据是难以处理的。 显示英文摘要

摘要： Coherent X-ray beams with energies $\geq 50$ keV can potentially enable three-dimensional imaging of atomic lattice distortion fields within individual crystallites in bulk polycrystalline materials through Bragg coherent diffraction imaging (BCDI). However, the undersampling of the diffraction signal due to Fourier space compression at high X-ray energies renders conventional phase retrieval algorithms unsuitable for three-dimensional reconstruction. To address this problem we utilize a phase retrieval method with a Fourier constraint specifically tailored for undersampled diffraction data measured with coarse-pitched detector pixels that bin the underlying signal. With our approach, we show that it is possible to reconstruct three-dimensional strained crystallites from an undersampled Bragg diffraction data set subject to pixel-area integration without having to physically upsample the diffraction signal. Using simulations and experimental results, we demonstrate that explicit modeling of Fourier space compression during phase retrieval provides a viable means by which to invert high-energy BCDI data, which is otherwise intractable.