Department of Mining and Materials Engineering, McGill University, 3610 Rue University, Montreal, Québec, Canada, H3A 0C5.
Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C-1), Wilhelm-Johnen Str., 52425 Jülich, Germany.
Ultramicroscopy. 2021 Jan;220:113166. doi: 10.1016/j.ultramic.2020.113166. Epub 2020 Nov 9.
Electron tomography has been widely applied to three-dimensional (3D) morphology characterization and chemical analysis at the nanoscale. A HAADF-EDS bimodal tomographic (HEBT) reconstruction technique has been developed to extract high resolution element-specific information. However, the reconstructed elemental maps cannot be directly converted to quantitative compositional information. In this work, we propose a quantification approach for obtaining elemental weight fraction maps from the HEBT reconstruction technique using the physical parameters extracted from a Monte Carlo code, MC X-ray. A similar quantification approach is proposed for the EDS-STEM tomographic reconstruction. The performance of the two quantitative reconstruction methods, using the simultaneous iterative reconstruction technique, are evaluated and compared for a simulated dataset of a two-dimensional phantom sample. The effects of the reconstruction parameters including the number of iterations and the weight of the HAADF signal are discussed. Finally, the two approaches are applied to an experimental dataset to show the 3D structure and quantitative elemental maps of a particle of flux melted metal-organic framework glass.
电子断层扫描技术已广泛应用于三维（3D）纳米尺度形貌特征和化学分析。本文开发了一种 HAADF-EDS 双模态断层重建（HEBT）技术，以提取高分辨率的元素特异性信息。然而，重建的元素图谱不能直接转换为定量成分信息。在这项工作中，我们提出了一种从 HEBT 重建技术中获取元素重量分数图谱的定量方法，该方法使用从蒙特卡罗代码 MC X-ray 中提取的物理参数。同时，还提出了一种用于 EDS-STEM 断层重建的定量重建方法。使用同时迭代重建技术，对二维幻影样品的模拟数据集进行了两种定量重建方法的性能评估和比较。讨论了重建参数（包括迭代次数和 HAADF 信号的权重）的影响。最后，将这两种方法应用于实验数据集，以显示通量熔融金属-有机骨架玻璃颗粒的 3D 结构和定量元素图谱。
