用多毛细管X射线透镜做光源的微区扫描型EDXRF仪器, 围绕出射焦斑对称放置4~6个SDD探测器, 设计软件控制X射线管、 多个探测器、 高精度移动平台, 同时进行数据采集、 信号同步和结果分析, 从而开发完成NX-mapping高通量微区扫描型EDXRF仪器。 由于多探测器的采用, 该仪器的信号强度得到数倍的提升, 且稳定性没有因为器件间的差异而变差, 同等条件, 同等用时的情况下, 测试标准偏差降为单探测器时的不足40%。 均匀样品2 mm×2 mm面扫描时, 400个点的测试标准偏差与定点测试无差异, 说明运动机构和控制算法表现优异, 不会对测试结果产生影响。 对于微区扫描仪器的焦斑尺寸, 用“荧光刀口实验”的方法, 对Fe, Ni和Mo元素进行了测试, 测得三种元素的有效焦斑尺寸最小值分别为52.4, 49.3和39.03 μm, 各元素有效焦斑尺寸随原子序数的增加而减小, 这与多毛细管X射线透镜的设计原理相符; 实验还发现了各元素焦斑有效尺寸在极小值处对高度变化较为敏感的规律, 因此建议为了得到统一清晰的扫描图像, 要保持样品表面的平整。 最后用NX-mapping仪器对某单晶高温合金样品的Ni, Ta, W和Re元素进行扫描和分布分析, 图像清晰, 枝晶结构明显可辨, 并且其中Ni∶Ka特征线强度高达220 kcps, 明显高于普通的XRF测试。 在NX-mapping微区扫描型EDXRF仪器中, 由于多探测器的采用, 信号强度高, 测试精密度好, 随之测试时间可以缩短, 因此可以满足高通量测试的需求。

A high-through put μ-EDXRF instrument named NX-mapping with polycapillary optics and 4~6 SDD detectors placed symmetrically around the emitted focal spot was developed. We designed the software to control the X-ray source, multiple detectors, and high-precision stage and carried out the work of data collection, signal synchronization and result in analysis simultaneously. Due to the use of multiple detectors, the intensity of this XRF instrument was improved several times, and the RSD was reduced to 40% hasn’t deteriorated due to the differences between several detectors and the moving stage.There is no significant difference between the RSD of scanning a uniform sample with 2 mm×2 mm square 400 pixels and the fixed-point test, indicating that the motion mechanism and control algorithm performed well. The fluorescent knife-edge test was carried out forthe effective focal size testing of NX-mapping. The minimum effective focal size of Fe, Ni and Mo elements are 52.4, 49.3 and 39.03 μm. The law that each element’s effective focal spot size decreases with the increase of atomic number is summarized, which is consistent with the design principle of polycapillary optics.It is also found that the effective size of the focal spot of each element is sensitive to the change of height at the minimum value. Therefore, it is recommended to keep the surface of the sample flat in order to obtain uniform and clear images.Finally, the characteristic intensity of elements Ni, Ta, W and Re of a single crystal superalloy sample were scanned and analyzed by NX-mapping. The images of the dendritic structure can be distinguished, and the intensity of the Ni∶Ka characteristic line was up to 220 kcps, which was significantly higher than that of the ordinary XRF test. The NX-mapping μ-EDXRF instrument with multiple detectors, which provide high signal intensity, good test precision and shorter test time,can meet the requirements of high-through put testing.