同步辐射X射线荧光分析

 近二、三十年来,X射线荧光分析(简称XRF)已成为物质中元素含量分析的基本手段,已广泛应用于物理、化学、生物、医学、法学、地学、材料科学等学科及工农业生产中.XRF是用X射线激发样品,并检测从样品中发射出的元素之特征X射线强度,分析样品中元素的含量.所谓特征X射线,是指每种元素的原子受激后会发射特定能量的X射线,它们是不连续的,是各自分立的.当原子内壳层中的电子受外来粒子作用而电离后,就会在内壳层留下一个空穴,于是较外层的电子就会跃迁到这个空穴,这就是所谓的退激发过程.     

同步辐射X射线荧光光谱国内外研究进展

同步辐射光源是带电粒子在加速器储存环中以接近光速的速度运动时,沿轨道切线方向发射出的辐射,同步辐射X射线荧光分析(SR-XRF)是以同步辐射X射线作为激发光源的X荧光光谱分析技术.同步辐射X射线荧光分析包括了用于微区及微量元素分析的同步辐射XRF、用于表面及薄膜分析的同步辐射全反射X射线荧光(SR-TXRF)以及用于三...     

同步辐射X射线三维显微成像

本介绍了利用同步辐射进行X射线三维成像的工作原理及进展状况,详细论述了X射线三维成像的两种方法,X射线全息及CT技术,以及通过两的结合（HCT）进行高分辨率三维成像的有关理论与实验技术;介绍了同轴全息中消除“双生像”噪声的数字方法,讨论了影响分辨率的各种因素;本还介绍了在国家同步辐射实验室软X射线实验站进行的生物样品X射线三维成像的实验及其结果。     

现代实验室型X射线荧光元素分布成像和形态分析技术的研究进展

近年来,随着X射线光源、单色、聚焦及探测系统的发展,在实验室可借助低功率X射线光源开展X射线荧光(XRF)和X射线吸收谱(XAS)分析。液体金属射流源等新型X射线光源系统、闭合反馈系统、电荷耦合元件和方孔微通道板等技术和计算方法的进步促进了聚焦扫描型、全场型和XRF计算机断层扫描等实验室型XRF元素空间成像技术的发展。超环面、球面和柱状弯晶等单色聚焦系统的发展推动了实验室型XAS技术的发展。探索新型的实验室X射线光源系统,开发更高效的单色聚焦系统,推动X射线动态电影拍摄技术等将是未来研究的重要发展方向。     

同步辐射全反射XRF实验

本文叙述了同步辐射全反射X射线荧光分析的实验装置和方法，给出了几种标准物质TXRF实验的检出限，我们已在细胞元素谱、体液和水样方面作了一些研究。并对实验结果进行了讨论。     

同步辐射X荧光分析中的逃逸峰的测量和计算

Si(Li)探测器引起的同步辐射X射线荧光(SR-XRF)谱中的逃逸峰,严重干扰利用XRF谱进行的定性和定量分析.对实验中的逃逸峰进行了鉴别.测定了14个样品的从K K_α到As K_α12个元素的标识谱的逃逸峰的强度和峰位.比较了逃逸峰与最近主峰能量差的实验值和标准值,一般误差小10%.用简化的X射线激发的Si K_α分布出射模型,计算元素逃逸峰强和其主峰强的比值,发现随原子序数增加,实验和理论比值都从约1%下降到0.1%左右.     

同步辐射微束荧光CT及其应用新进展

同步辐射微束X射线荧光CT（SR-XFCMT）是将传统的X射线荧光分析法和计算机断层成像（CT）技术有机结合发展起来的一种先进的分析技术．SR-XFCMT可以给出元素在样品内部的分布而不需要对样品进行破坏性的处理，现已成为很多研究领域的有力工具．文章简要介绍了同步辐射微束荧光CT技术及其应用的最新进展，阐述了同步辐射微束X射线荧光CT的关键问题及其发展的前景.     

氧化镓的同步辐射研究

 利用金刚石对顶砧（DAC）高压装置产生高压，使用体积比为16∶3∶1的甲醇、乙醇和水混合液作为传压介质，通过原位高压同步辐射技术对氧化镓的高压行为进行了研究（0～42.5 GPa）。实验发现在室温下13.3 GPa压力附近，单斜结构的氧化镓发生了结构相变，变成三角结构。相变后镓离子由原来同时位于由氧离子围成的四面体和八面体的中心位置变成只位于八面体的中心位置。卸压后的X射线衍射谱表明，氧化镓又恢复为单斜结构，该相变为可逆相变。     

同步辐射讲座 第三讲 软X射线显微术

对生物样品的研究，软X射线显微术具有独特的优势，例如，它能够对较厚的活性含水的生物样品直接进行显微成像以及元素分布的微区分析等，文章简要论述了软X射线显微术的衬度机制及其优势；列表概括了包括SCXM，TXM，STXM，Gabor全息以及衍射等几种类型的X射线显微术的基本特性；简要综述了合肥国家同步辐射实验室（NSRL）软X射线显微术的研究进展。     

整体毛细管X光透镜在大气颗粒物单颗粒分析中的应用

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30 μm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9 μm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.     

Review of in situ X-ray fluorescence analysis technology in China

In the past two decades, the in situ X-ray fluorescence (XRF) technology has been developed rapidly in China, which is mainly due to the rapid development of China's economy and the great demand for rapid qualitative and quantitative analysis of elements in geological exploration, environmental protection, and industrial process analysis. In this article, the development of in situ XRF analysis technology in China is reviewed from three aspects, namely in situ XRF analyzers, in situ XRF analysis technology, and applications of in situ XRF analysis technology. The in situ XRF analyzers are divided into four generations, and the technical characteristics of each generation of analyzers are discussed from the perspectives of X-ray excitation source, detector, electronic circuit unit, and digital signal processing. The progress of X-ray spectrum analysis, matrix effect correction, and correction of uneven effect and humidity effect is reviewed. The representative applications of XRF analysis technology in geological and mineral survey, environmental pollution investigation, cultural relic identification, and alloy analysis are introduced.     

毛细管X光透镜三维共聚焦微束X射线荧光技术在岩矿样品分析中的应用

利用毛细管X光透镜搭建了三维共聚焦微束X射线荧光谱仪,处在激发道的多毛细管X射线会聚透镜和处在探测道的多毛细管X射线平行束透镜处于共聚焦状态,该共聚焦结构降低了X射线荧光光谱的背底,从而有利于降低的X射线荧光分析技术的探测极限。在上述共聚焦结构中,多毛细管X射线会聚透镜和多毛细管X射线平行束透镜的焦斑重合形成共聚焦微元,探测器只能探测到来自该共聚焦微元内的X射线荧光信号,当该共聚焦微元在样品移动时,就可利用该共聚焦技术原位无损得到样品内部的三维X射线荧光信息。该共聚焦技术使用的多毛细管X射线会聚透镜具有103量级的功率放大倍数,从而降低了该共聚焦技术对高功率X射线源的依赖程度,即利用低功率普通X射线源就可以设计毛细管X光透镜共聚焦X射线荧光技术。利用上述共聚焦微束X射线荧光谱仪对两种岩矿样品进行三维无损分析,在其中一种岩石中发现：Fe浓度大的区域Cu的浓度也大,这在一定程度上反映了岩矿自然生长的机理。实验结果证明：该共聚焦X射线荧光技术可以在不破坏样品情况下分析岩矿样品中元素成分组成和元素三维分布情况。该共聚焦三维微束X射线荧光技术在矿石勘察、玉器选材和鉴别、石质食用器皿、“赌石”和家用石质地板检测等领域具有潜在的应用。     

Application of Three Dimensional Confocal Micro X-Ray Fluorescence Technology Based on Polycapillary X-Ray Lens in Analysis of Rock and Mineral SamplesSCIEI北大核心CSCD

Confocal three dimensional (3D) micro X-ray fluorescence (XRF) spectrometer based on a polycapillary focusing X-ray lens (PFXRL) in the excitation channel and a polycapillary parallel X-ray lens (PPXRL) in the detection channel was developed. The PFXRL and PPXRL were placed in a confocal configuration. This was helpful in improving the signal-to-noise ratio of the XRF spectra, and accordingly lowered the detection limitation of the XRF technology. The confocal configuration ensured that only the XRF signal from the confocal micro-volume overlapped by the output focal spot of the PFXRL and the input focal spot of the PPXRL could be detected by the detector. Therefore, the point-to-point information of XRF for samples could be obtained non-destructively by moving the sample located at the confocal position. The magnitude of the gain in power density of the PFXRL was 10(3). This let the low power conventional X-ray source be used in this confocal XRF, and, accordingly, decreased the requirement of high power X-ray source for the confocal XRF based on polycapillary X-ray optics. In this paper, we used the confocal 3D micro X-ray fluorescence spectrometer to non-destructively analyzed mineral samples and to carry out a 3D point-to-point elemental mapping scanning, which demonstrated the capabilities of confocal 3D micro XRF technology for non-destructive analysis elements composition and distribution for mineral samples. For one mineral sample, the experimental results showed that the area with high density of element of iron had high density of copper. To some extent, this reflected the growth mechanisms of the mineral sample. The confocal 3D micro XRF technology has potential applications in such fields like the analysis identification of ore, jade, lithoid utensils, "gamble stone" and lithoid flooring.     

Optimization of a primary X-ray filter for X-ray fluorescence analysis of uranium and plutonium

When workers are wounded at a nuclear fuel handling facility, it is difficult to quantify actinide contamination through α-particle counting because these particles are shielded by blood. To overcome this problem, we used X-ray fluorescence (XRF) analysis with a handheld-type device that is useful in cases where sampling is not allowed, such as in this study. In XRF analysis, a primary X-ray filter made of metal foil is generally inserted between the X-ray tube and the sample to attenuate the incident X-ray at the energy region of the XRF signal for the target element. Doing so can reduce the background signal originating from the scattered radiation of the incident X-ray. In this study, we aimed to optimize a primary X-ray filter that facilitates simultaneous high-sensitivity analysis of uranium and plutonium in a wound. For this purpose, XRF measurements were performed for a needle-puncture wound model contaminated by U and Pu, and the relationship between the filter material/thickness and the detection limit was investigated. Optimizing the filter material/thickness of a given target element was found to improve the detection limit of the measurement by ~10%.     

在XRF多变元体系因素分析中应用交互有效法选择体系的主组份

本文报道了在X-射线荧光分析多变元体系因素分析中,应用交互有效法选择体系主组份的研究。本方法在基本参数法的基础上,运用交互有效法,通过最小预报残差平方和(PRESS)的计算,对体系进行了主组份分析,确定了该体系中的最佳维数和主要影响因素。选择体系中的主组份进行回归分析,剔去了噪声,模型稳定性增强,XRFA的预报能力和分析结果准确度有了显著的提高。文中给出了分析地质样品中十三个主、次量元素的实验结果和数据对照。     

利用毛细管X光透镜共聚焦微束X射线荧光技术对单根头发中元素空间分布进行无损扫描分析

头发中的元素与人的饮食和健康状况有关,对头发中元素的分析,不仅可用于刑事物证鉴别,还可为疾病的预防和治疗提供依据,因此,如何检测头发中元素分布等信息倍受人们关注。本文利用基于毛细管X光透镜和实验室普通X射线光源的共聚焦微束X射线荧光技术对单根头进行了无损扫描分析,分析了单根头发中元素的空间分布。在该毛细管X光透镜共聚焦微束X射线荧光技术中,毛细管X光会聚透镜的出口焦斑和毛细管X光平行束透镜的入口焦斑处在共聚焦状态,从而形成共聚焦微元,探测器只能探测到来自该共聚焦微元中的X射线信号,降低了背底信号对X射线荧光谱的影响,从而有利于提高该共聚焦X射线荧光技术的分析精度。该共聚焦技术中采用了具有高功率密度增益的毛细管X光会聚透镜,降低了该共聚焦X射线荧光技术对X射线光源功率的要求,从而保证了该共聚焦技术可以采用实验室普通X射线光源,降低了实验成本。实验表明,毛细管X光透镜共聚焦微束X射线荧光技术在单根头发元素分布检测中具有应用价值。     

Application of artificial neural networks to X-ray fluorescence spectrum analysis

X-ray fluorescence (XRF) is widely applied as a mature nondestructive testing method, and appropriate improvement of quantitative analysis methods can improve the accuracy of XRF. Artificial neural network is an intelligent information processing system, its developments and application in XRF are reviewed, and representative models (back propagation, radial basis function, genetic algorithm artificial neural network, and others) are discussed in more details in overfitting, generalization, and algorithm efficiency. Potential directions of developing artificial neural network applied in XRF are proposed in this review as a further study.     

行波管用钨铼合金中高含量铼的X射线荧光光谱测定

根据行波管用的关键材料-钨铼合金中高含量铼测定的需求,研究了用X射线荧光(XRF)光谱法测定铼时所存在的基体效应、谱线重叠和背景干扰的影响,从理论上解释了XRF二元比例法校正曲线线性差的原因。理论和实验结果均表明：直接用Re Lα分析线强度绘制的校正曲线比二元比例法可以获得更好的线性。本法具有快速准确的特点,分析结果与化学方法一致,在生产控制中应用效果显著。