整体毛细管X光透镜在大气颗粒物单颗粒分析中的应用

Application of Monolithic Capillary X-Ray Lens in Analysis of Single Aerosol Particles

对大气颗粒物进行单颗粒X射线荧光(XRF)分析,是一种识别大气颗粒物来源的有力手段。为了利用实验室X射线光源对大气颗粒物进行单颗粒XRF分析,建立了基于整体毛细管X光透镜和实验室X射线光源的微束X射线谱仪。透镜焦斑处的功率密度增益在103数量级,焦斑直径为30μm左右。该微束X射线谱仪对Fe-Kα线的最小探测极限为0.7 pg。在Mo靶光源电压和电流分别为30 kV和50 mA的条件下,利用该谱仪对直径为9μm的大气颗粒物单颗粒进行XRF分析时,测谱时间在180 s左右。实验表明,基于毛细管X光透镜和实验室X射线光源的微束X射线分析技术在大气颗粒物单颗粒分析中有着潜在的应用价值。

X-ray fluorescence （XRF） analysis of single aerosol particles is a useful tool for identifying origins of aerosol particles. A micro-XRF spectrometer based on a monolithic capillary X-ray lens （MCXRL） and laboratory X- ray source is designed in order to carry out the XRF analysis of single aerosol particles. The order of magnitude of the gain of power density of the MCXRL is 10^3 at the focal spot, and the focal spot size of the MCXRL is about 30 μm. The minimum detection limit （MDL） of this spectrometer is 0.7 pg for the Fe-Ka. The XRF spectrum of a single aerosol particle with a diameter of 9μm is obtained within 180 s when the working voltage and current of a Mo rotating anode X-ray generator are 30 kV and 50 mA, respectively. The experimental results show that the designed spectrometer has potential applications in the analysis of single aerosol particles.