一种毛细管聚焦的微束X射线衍射仪

A new type of micro-X-ray diffractometer focused by polycapillary optics

微区X射线衍射(micro-X-ray diffraction)分析在测量小样品或样品微区结构方面有着独特的优势.介绍了实验室自行研发的台式毛细管聚焦的微束X射线衍射仪(μ-Hawk),其主要由微焦斑X射线管、毛细管X光透镜、接收狭缝、SDD X射线探测器、θ-θ测角仪、三维样品台,以及在Lab VIEW语言环境下开发的计算机控制程序等部分组成.控制程序的主界面具备微区X射线衍射分析和微区能量色散X射线荧光分析两种分析模式.为了验证设备的可行性,分别对一枚人民币五角硬币上"角"字第一划中央处的微区和直径为140μm的铜质导线进行微区点分析;对苹果手机主板焊锡接触点上1.0 mm×0.6 mm区域内的物相分布进行二维扫描分析,具体方式为在二维待测区域内逐点自动执行θ-θ角度扫描,由程序控制的4个电机来实现此过程.分析结果表明,μ-Hawk所具备的微区能量色散X射线荧光分析模式,为物相结构的识别提供了元素种类的参考信息;与常规的X射线衍射仪相比较,μ-Hawk所采集的衍射图整体本底较低,并且所测得的衍射峰位置基本一致;μ-Hawk能适应小样品或样品微区物相结构的分析和物相分布的二维扫描分析,在材料科学、地球科学和文物保护等领域有着广泛的应用前景.

Micro-X-ray diffraction(μ-XRD)plays a significant role in measuring the phase structures of small samples or micro areas of larger samples.In this article,we propose a new type of desktop micro-X-ray diffractometer namedμ-Hawk focused by polycapillary optics.It consists mainly of a microfocus X-ray tube,polycapillary optics,receiving slits,a silicon drift diode(SDD)X-ray detector integrated with single/multi-channel pulse analyzer,independently rotatingθ-θgoniometer,high precision XYZ sample stage,computer programs developed by LabVIEW codes,etc.The main interface of the program has micro-X-ray diffraction analysis mode and micro energy dispersive X-ray fluorescence analysis mode.In addition,the monochromatization of Xray,the angular resolution and the accuracy of the results ofμ-Hawk are discussed.In order to demonstrate the feasibility of the instrument,the phase of micro area in the middle of the first stroke on the Chinese character"Jiao"from a 5-Jiao coin(Chinese currency)is measured by theμ-Hawk,and the phase of a copper wire 140μm in diameter is also detected by it.After that,the phase of 1.0 mm×0.6 mm area on the welding joint of the motherboard from an iPhone is two-dimensionally scanned byμ-Hawk.Theθ-θscanning is performed at each detected point inside the two-dimensional area.Four motors drive the X and Y axis of the sample stage as well as the q1 and q2 axis of the goniometer to accomplish the above functions.The results show that the micro energy dispersive X-ray fluorescence analysis mode ofμ-Hawk can provide elementary reference information for the analysis of phase structure.Compared with conventional X-ray diffractometer,theμ-Hawk can detect the same diffraction peaks on the coin with lower background.Furthermore,the accurate diffraction peaks can be measured with a lower power and shorter time.The measured results can better reflect the true phase structure of the micro area.Six diffraction peaks and their phases can be clearly identified from the diffraction pattern of the copper wire.For the welding joint,the phase mapping of SnO2(312)is acquired through data processing.Therefore,theμ-Hawk can adapt to the micro-X-ray diffraction analysis of small samples or micro areas of samples as well as the two-dimensional scanning analysis of phase mapping.Theμ-Hawk exhibits the unique advantages of accomplishing accurate micro-X-ray diffraction analysis,convenient software,low working power,time saving,and small in size.It indicates a wide application prospect in the fields of materials,geosciences and heritage protection.