Yoneyama Akio, Kawamoto Masahide, Baba Rika
SAGA Light Source, 8-7 Yayoigaoka, Tosu, 841-0005, Japan.
Research and Development Group, Hitachi Ltd., 1-280 Higashi-koigakubo, Kokubunji, 185-8601, Japan.
Sci Rep. 2019 Dec 11;9(1):18831. doi: 10.1038/s41598-019-54907-3.
Elemental kinds, composition ratios, effective atomic number (Z), and spatial distributions are the most basic information on materials and determine the physical and chemical properties of materials. X-ray fluorescence analysis have conventionally been used for elemental mapping, however maps on deep internal areas cannot be obtained because the escape depth of fluorescence X-rays is limited to a few mm from the surface of samples. Herein, we present a novel Z imaging method that uses back-scattered X-rays. The intensity ratio of elastic and inelastic back-scattered X-rays depends on the atomic number (Z) of a single-element sample (Z for a plural-element sample), and so Z maps in deep areas can be obtained by spectrum analysis of the scattered high-energy incident X-rays. We demonstrated the feasibility of observing a phantom covered by an aluminum plate by using synchrotron radiation X-ray. A fine Z map that can be used to identify materials was obtained from only front-side observation. The novel method opens up a new way for Z mapping of deep areas of thick samples from front-side observation.
元素种类、组成比例、有效原子序数（Z）和空间分布是材料最基本的信息，它们决定了材料的物理和化学性质。传统上，X射线荧光分析用于元素成像，然而由于荧光X射线的逸出深度仅限于距样品表面几毫米，因此无法获得深部区域的图像。在此，我们提出一种利用背散射X射线的新型Z成像方法。弹性和非弹性背散射X射线的强度比取决于单元素样品的原子序数（对于多元素样品为Z），因此可以通过对散射的高能入射X射线进行光谱分析来获得深部区域的Z图像。我们利用同步辐射X射线证明了观察铝板覆盖的体模的可行性。仅通过正面观察就获得了可用于识别材料的精细Z图像。这种新方法为从正面观察厚样品深部区域的Z成像开辟了一条新途径。
