三晶体多轴联动同步辐射X射线荧光光谱仪

摘要

针对上海光源X射线吸收精细结构光谱仪对灵敏度和分辨率的要求,研制了三晶体多轴同步辐射X射线荧光光谱仪.其采用一台双晶单色器提供实验X射线,用3块凹面晶体构成系统主体色散结构,并在竖直平面内组成相交的罗兰圆实现荧光分析,可实现10°范围内的布拉格角变化.光谱仪通过高精度控制驱动设备使位移平台实现了3块晶体的4轴联动和总台的2轴联动,其中对位移平台的各轴精度达到了单步长移动25nm,可以实现高分辨率的三维扫描工作.编写了探测器的驱动软件,提高了驱动器的测试灵敏度和分辨率.最后,利用国际通用的实验物理控制系统——EPICS(Experiment Physics and Industrial Control System)完成了整个系统软件的设计,实现了系统各部分的精确控制、自动测量、数据分析和结果显示与存储等功能,构成了一套完整的基于同步辐射光源的高精度高分辨率X射线荧光光谱分析系统.采用钴元素作为测试样品进行了分析实验,结果显示:该光谱仪单次测量时间小于1.5s,测试精度达到0.4eV,分辨率为0.1 eV.光谱仪可以完成对样品荧光的采集和分析,操作时间、精度、分辨率和重复性等性能指标均优于现有国内、外设备,目前已成功应用于上海光源XAFS线站的各项科学实验中.%To meet the requirements of the X-ray fluorescence spectrometer in Shanghai Synchrotron Radiation Facility(XAFS) for sensitivity and resolution ,a synchrotron radiation X-ray fluorescence spectrometer was proposed based on three-crystal and multi-axis linkage .In experiments ,the X-ray was provided by a double crystal monochromator ,the dispersion structure was made of three concave crystals and these crystals formed an intersectant Rowland circle in the vertical plane to achieve the fluorescent analysis .Moreover ,the dispersion structure could change in the Bragg angle ranges of 10° .Four-axis linkage of three crystal and two-axis linkage of the whole platform were implemented by high precisely controlling the driving device .Here ,the displacement precision of each axis reaches 25 nm in a single step ,which realizes high resolution and three-dimensional scanning work .The driver's software was programmed to improve the test sensitivity and resolution of the driver .The overall system software was designed by using the International Common Experimental Physical Control System-EPICS .By w hich ,the spectrometer realizes the functions such as the precise control , automatic measurement ,data analysis ,results display and storage functions and completes a high precision and high resolution X-ray fluorescent spectrum analysis system based on Synchrotron Radiation Source . By taking the cobalt as the experimental sample , an analysis experiment was performed .The results show that the single measurement time is less than 1 .5 s ,the test precision is 0 .4 eV and the resolution is 0 .1 eV .T he spectrometer can acquire and analyze the fluorescence of the sample and the operating time ,precision ,resolution and the repeatability are superior to those of the existing domestic and foreign equipment .It has been used in the scientific research experiments of Shanghai light source XAFS line .