样品厚度对薄膜法X射线荧光光谱测量的影响研究

发布时间：2018-10-13 16:19

【摘要】：分别以富集有Cr,Pb和Cd三种元素的尼龙薄膜样品及玻璃纤维滤膜为研究对象,采用滤膜叠加的方式,通过XRF光谱仪测量不同样品厚度下薄膜样品的XRF光谱,根据测得的尼龙薄膜样品中Cr,Pb,Cd元素及玻璃纤维滤膜中Ca,As和Sr元素特征XRF性质的变化,研究样品厚度对薄膜法XRF光谱测量的影响。结果表明:薄膜样品厚度对不同能量区间上元素特征谱线荧光性质的影响并不相同。元素特征谱线能量越大,元素特征X射线荧光穿透滤膜到达探测器的过程中损失越少;但由薄膜样品厚度增加引起的基体效应却越强,相应特征谱线位置处的背景荧光强度就越大,因此样品厚度增加所引起的基体效应对薄膜法XRF光谱测量的灵敏度影响就越大。对于特征谱线能量较低(能量小于7keV)的元素,以增加薄膜样品厚度的方式来增加待测组分的质量厚度浓度,并不能有效地提高薄膜法XRF光谱测量的灵敏度;对于特征谱线能量较高的元素(能量7keV),可以通过适当增加样品厚度以增加被测组分的质量厚度浓度的方式来提高XRF光谱测量的灵敏度,薄膜样品厚度在0.96~2.24mm内,更有利于XRF光谱的测量与分析。该研究为大气及水体重金属薄膜法XRF光谱分析中薄样制备及富集技术提供了重要的理论依据。
[Abstract]:The samples of nylon film and glass fiber filter membrane enriched with Cr,Pb and Cd were studied respectively. The XRF spectra of the film samples with different thickness were measured by XRF spectrometer by means of the superposition of the filter membrane. According to the changes of the characteristic XRF properties of Cr,Pb,Cd in nylon film and Ca,As and Sr in glass fiber filter membrane, the influence of sample thickness on XRF spectrum measurement by thin film method was studied. The results show that the thickness of thin films has different effects on the fluorescence properties of element characteristic lines in different energy ranges. The larger the energy of the element characteristic line, the less the loss of the element characteristic X-ray fluorescence penetrating filter membrane to the detector, but the stronger the matrix effect caused by the increase of the thickness of the film sample. The higher the background fluorescence intensity at the location of the corresponding characteristic line, the greater the influence of the matrix effect caused by the increase of the sample thickness on the sensitivity of the thin film XRF spectroscopy measurement. For the element with low characteristic line energy (energy less than 7keV), increasing the mass thickness concentration of the component by increasing the thickness of the film sample can not effectively improve the sensitivity of the XRF spectrum measurement by the thin film method. For the element (energy 7keV) with higher characteristic line energy, the sensitivity of XRF spectrum measurement can be improved by increasing the thickness of the sample to increase the mass thickness concentration of the measured component. The thickness of the film sample is in 0.96~2.24mm. It is more favorable to the measurement and analysis of XRF spectra. This study provides an important theoretical basis for the preparation and enrichment of thin samples in the XRF spectroscopic analysis of heavy metals in atmospheric and water bodies.
【作者单位】：中国科学院安徽光学精密机械研究所环境光学与技术重点实验室安徽省环境光学监测技术重点实验室;皖江新兴产业技术发展中心;中国人民解放军陆军军官学院;
【基金】：皖江新兴产业技术发展中心企业合作项目(ZNJX-15-10) 国家(863)计划项目(2013AA065502) 国家自然科学基金项目(61405257) 安徽省自然科学基金项目(1508085MF138) 安徽省自主创新专项(12Z0104074)资助
【分类号】：O657.34

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