EDXRF中几何探测光路分析及其优化设计

能量色散X射线荧光分析因其分析速度快、准确度高、分析过程简单等优势已经广泛的应用到医疗、考古等诸多领域。探测光路的最优化设计可以减小仪器散射本底,降低检出限,提高仪器的分辨率及探测效率,增强特征X射线的全能峰的峰背比,改善仪器的工作性能。应用自制的一款低检出限、高分辨率的能量色散X射线荧光分析仪,通过对纯元素Cu特征X射线探测完成了光谱仪几何光路最优化设计。实验结果表明,X射线管与样品的夹角、样品与探测器的夹角均为45°,X射线管到样品、样品到探测器的距离均为10mm时,特征X射线的峰背比最佳。同时将Al-Pb准直加装在光路中进行本底测量,散射本底以及仪器的检出限大大降低,提高了仪器的分辨率及探测效率,为痕量和微量元素的分析提供了优化的光路解决方案。

Analysis of geometric detecting optical path and optimization design in EDXRF

Energy dispersive X-ray fluorescence analysis with the advantages of fast analysis speed, high accuracy and the simple process has been widely applied to many fields such as medicine and archaeology. The optimization design of detection optical path can decrease scattering background, reduce detection limit, improve resolution and detection efficiency, and enhance the peak-to-background ratio of characteristic X-ray to the instrument. Application of a self-made energy dispersive X-ray fluorescence analyzer with low detection limit and high-resolution, the optimization geometry layout design of optical path was established by detecting pure Cu elements characteristic X-ray. The experimental results showed the peak-to-background ratio of the characteristic X-ray was the best when the angle between X-ray tube and the sample, the sample and the detector were both 45° as well as the distance of X-ray tube to the sample and the sample to the detector were both 10mm respectively. When the AI-Pb collimator was installed in the optical path for the background measurement, the scattering of background and the detection limit of the instrument were reduced and the resolution and detection efficiency was improved greatly. It supplied the best solution for the design of the optimal optical path to analyze the trace and micro elements.