Fang Haixing, Ludwig Wolfgang, Lhuissier Pierre
Université Grenoble Alpes, Grenoble INP, CNRS SIMaP, 1130 Rue de la Piscine, 38402 Saint Martin d'Hères, France.
European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France.
J Appl Crystallogr. 2023 May 31;56(Pt 3):810-824. doi: 10.1107/S1600576723003874. eCollection 2023 Jun 1.
Laboratory-based diffraction contrast tomography (LabDCT) is a novel technique used to resolve grain orientations and shapes in three dimensions at the micrometre scale using laboratory X-ray sources, allowing the user to overcome the constraint of limited access to synchrotron facilities. To foster the development of this technique, the implementation of LabDCT is illustrated in detail using a conventional laboratory-based X-ray tomography setup, and it is shown that such implementation is possible with the two most common types of detectors: CCD and flat panel. As a benchmark, LabDCT projections were acquired on an AlCu alloy sample using the two types of detectors at different exposure times. Grain maps were subsequently reconstructed using the open-source grain reconstruction method reported in the authors' previous work. To characterize the detection limit and the spatial resolution for the current implementation, the reconstructed LabDCT grain maps were compared with the map obtained from a synchrotron measurement, which is considered as ground truth. The results show that the final grain maps from measurements by the CCD and flat panel detector are similar and show comparable quality, while the CCD gives a much better contrast-to-noise ratio than the flat panel. The analysis of the grain maps reconstructed from measurements with different exposure times suggests that a grain map of comparable quality could be obtained in less than 1 h total acquisition time without a significant loss of grain reconstruction quality and indicates a clear potential for time-lapse LabDCT experiments. The current implementation is suggested to promote the generic use of the LabDCT technique for grain mapping on conventional tomography setups.
基于实验室的衍射对比断层扫描（LabDCT）是一种新技术，用于使用实验室X射线源在微米尺度上三维解析晶粒取向和形状，使用户能够克服使用同步加速器设施受限的问题。为促进该技术的发展，本文详细说明了使用传统的基于实验室的X射线断层扫描装置来实现LabDCT，并表明使用两种最常见的探测器：电荷耦合器件（CCD）和平板探测器都可以实现。作为基准，使用这两种探测器在不同曝光时间对AlCu合金样品采集LabDCT投影。随后使用作者之前工作中报道的开源晶粒重建方法重建晶粒图。为表征当前实现方式的检测限和空间分辨率，将重建的LabDCT晶粒图与从同步加速器测量获得的图进行比较，后者被视为真实情况。结果表明，由CCD和平板探测器测量得到的最终晶粒图相似且质量相当，而CCD的对比度噪声比远优于平板探测器。对不同曝光时间测量重建的晶粒图分析表明，在总采集时间不到1小时的情况下，可以获得质量相当的晶粒图，且晶粒重建质量不会有显著损失，这表明时间推移LabDCT实验具有明显潜力。建议当前的实现方式可促进LabDCT技术在传统断层扫描装置上进行晶粒映射的广泛应用。
