3-Dimensional Element Mapping with X-ray Fluorescence Imaging Microscope

x射线荧光已被用来研究材料的组成。x射线荧光光谱确定了一种特定的元素。到目前为止，由于缺乏x射线成像设备，三维元素映射是非常困难的。筑波大学开发的Wolter镜使我们能够直接成像x射线荧光。x射线荧光成像显微镜（XFIM）由x射线源（同步辐射）、物镜（沃尔特镜）和x射线区域探测器（CCD相机）组成。我们使用的同步辐射设备是光子工厂（BL3C2）和Spring-8（BL39XU）。我们可以得到原子序数在20(Ca) ~ 30（Zn）之间的x射线荧光图像。利用CCD相机旋转样品，对50幅x射线荧光图像进行了三维元素映射。Wolter镜的放大倍率为10，它可以成像高达12kev的x射线荧光。镜面分辨率大于10 μm。x射线荧光成像显微镜检测灵敏度优于1 pg/pixel。记录并重构了铁、铜、镍导线的试样。还记录了合成金刚石的包裹体，得到了Fe、Co和Ni的三维分布。成功地对硫酸铜电解过程中的Cu沉积进行了动态观察，结果表明该显微镜具有较大的观察深度。通过使用x射线荧光成像显微镜，许多非破坏性观察的其他应用将成为可能。

X-ray fluorescence has been used to investigate the composition of materials. The spectrum of x-ray fluorescence defines a specific element. So far, being the lack of x-ray imaging device 3-dimensional element mapping was very difficult. A Wolter mirror which has been developed in the University of Tsukuba enables us to image x-ray fluorescence directly. The x-ray fluorescence imaging microscope(XFIM) consists of an x-ray source (synchrotron radiation), an objective mirror(Wolter mirror) and an x-ray area detector(CCD camera).Synchrotron radiation facilities we used were the Photon Factory(BL3C2) and the Spring-8(BL39XU). We could obtained x-ray fluorescence images whose atomic numbers are from 20(Ca) to 30(Zn). 3-dimensional element mapping was succeeded from fifty x-ray fluorescence images which were recorded with a CCD camera by rotating a sample. The magnification of the Wolter mirror was 10 and it can image x-ray fluorescence up to 12 keV. The resolving power of the mirror is better than 10 μm. The detection sensitivity of the x-ray fluorescence imaging microscope was better than 1 pg/pixel. Test samples of Fe, Cu and Ni wires were recorded and reconstructed. The inclusions of a synthesized diamond were also recorded and 3-dimensional distribution of Fe, Co and Ni could be obtained.Dynamical observation of Cu deposition at copper sulfate electrolysis was succeeded, which demonstrated that the microscope has a relatively large depth of view. Many other applications of non-destructive observation will be possible by using an x-ray fluorescence imaging microscope.