Palo Alto High School, Palo Alto, California, 94301.
Microsc Res Tech. 2013 Nov;76(11):1112-7. doi: 10.1002/jemt.22273. Epub 2013 Aug 6.
Transmission X-ray microscopy (TXM) is a rapidly developing technique with the capability of nanoscale three dimensional (3D) real-space imaging. Combined with the wide range in energy tunability from synchrotron sources, TXM enables the retrieval of 3D microstructural information with elemental/chemical sensitivity that would otherwise be inaccessible. The differential absorption contrast above and below absorption edges has been used to reconstruct the distributions of different elements, assuming the absorption edges of the interested elements are fairly well separated. Here we present an "Absorption Correlation Tomography" (ACT) method based on the correlation of the material absorption across multiple edges. ACT overcomes the significant limitation caused by overlapping absorption edges, significantly expands the capabilities of TXM, and makes it possible for fully quantitative nano-scale 3D structural investigation with chemical/elemental sensitivity. The capability and robustness of this new methodology is demonstrated in a case study of an important type of rare earth magnet (Nd₂Fe₁₄B).
透射 X 射线显微镜（TXM）是一种快速发展的技术，具有纳米级三维（3D）实时成像的能力。结合同步辐射源在能量调节范围上的优势，TXM 可以获取具有元素/化学敏感性的 3D 微观结构信息，而这些信息在其他情况下是无法获得的。在吸收边以上和以下的差分吸收对比已被用于重建不同元素的分布，假设感兴趣元素的吸收边相当好地分离。在这里，我们提出了一种基于多边缘材料吸收相关性的“吸收相关断层扫描”（ACT）方法。ACT 克服了重叠吸收边引起的显著限制，显著扩展了 TXM 的功能，并使其有可能进行具有化学/元素敏感性的全定量纳米尺度 3D 结构研究。这种新方法的能力和稳健性在对一种重要类型的稀土磁铁（Nd₂Fe₁₄B）的案例研究中得到了证明。
