First X-ray fluorescence CT experimental results at the SSRF X-ray imaging beamline

X-ray fluorescence CT is a non-destructive technique for detecting elemental composition and distribution inside a specimen. In this paper, the first experimental results of X-ray fluorescence CT obtained at the SSRF X-ray imaging beamline (BL13W1) are described. The test samples were investigated and the 2D elemental image was reconstructed using a filtered back-projection algorithm. In the sample the element Cd was observed. Up to now, the X-ray fluorescence CT could be carried out at the SSRF X-ray imaging beamline.     

利用荧光CT实现生物医学样品内元素分布的无损成像

荧光CT是一种可无损重建元素空间分布的发射型断层成像技术,对生物医学研究具有重要意义.同步辐射的高通量、高准直和能量可调等特性使荧光CT的生物医学应用成为可能.文章通过优化设计,在上海同步辐射光源建立了一套用于生物医学样品微量元素分析的荧光CT成像系统.通过对实验装置的优化,提高了系统的数据采集速度和空间分辨率.将极大...     

上海光源硬X射线相干衍射成像实验方法初探

相干X射线衍射成像方法是一种先进的成像技术,分辨率可达纳米量级.国际上大多数的同步辐射装置和自由电子激光装置都建立了该成像方法,并有将其作为主要成像技术的趋势.上海光源作为目前国内唯一的一台第三代同步辐射光源,尚未建立基于硬X射线的相干衍射成像实验平台.随着一批以波荡器为光源的光束线站投入使用,使得该方法的建立成为了可能.本文基于上海光源BL19U2生物小角散射线站,通过有效的光路设计,搭建了相干衍射实验平台,在12 keV和13.5 keV能量点均获得了硬X射线相干光束,并基于小孔衍射测量了入射光束的空间相干长度.该平台支持常规和扫描相干衍射实验模式,对小孔衍射图样及波带片扫描衍射图样实现了正确的相位重建,证明了该平台初步具备开展硬X射线相干衍射成像实验的能力.硬X射线相干衍射成像实验平台为国内首次建立,将为国内该实验方法的发展和应用提供有效的软硬件支持.     

基本参数法在地面验证实验中的的应用

As the nearest celestial body to the earth, the moon has become a hot spot again in astronomy field recently. The element analysis is a much important subject in many lunar projects. Remote X-ray spectrometry plays an important role in the geochemical exploration of the solar bodies. Because of the quasi-vacuum atmosphere on the moon, which has no absorption of X-ray, the X-ray fluorescence analysis is an effective way to determine the elemental abundance of lunar surface. The CE-1 X-ray fluorescence spectrometer （CE-1/XFS） aims to map the major elemental compositions on the lunar surface. This paper describes a method for quantitative analysis of elemental compositions. A series of ground base experiments are done to examine the capability of XFS. The obtained results, which show a reasonable agreement with the certified values at a 30% uncertainty level for major elements, are presented.     

Quantitative analysis results of CE-1 X-ray fluorescence spectrometer ground base experiment

As the nearest celestial body to the earth, the moon has become a hot spot again in astronomy field recently. The element analysis is a much important subject in many lunar projects. Remote X-ray spectrometry plays an important role in the geochemical exploration of the solar bodies. Because of th equasi-vacuum atmosphere on the moon, which has no absorption of X-ray, the X-ray fluorescence analysis is an effective way to determine the elemental abundance of lunar surface. The CE-1 X-ray fluorescence spectrometer (CE-1/XFS) aims to map the major elemental compositions on the lunar surface. This paper describes a method for quantitative analysis of elemental compositions. A series of ground base experiments are done to examine the capability of XFS. The obtained results, which show a reasonable agreement with the certified values at a 30% uncertainty level for major elements, are presented.     

Confocal three-dimensional micro X-ray fluorescence based on synchrotron radiation for mineral analysis

The confocal three-dimensional micro X-ray fluorescence using polycapillary optics and a synchrotron radiation was applied to nondestructively analyze elemental compositions of minerals, and thereby obtain the three-dimensional distributions of elements in the minerals. Such confocal micro X-ray fluorescence had potential applications in the mineral prospecting, identification of jades, differentiation of stones.     

Advances in the histopathological characterization of breast tissue using combined X-ray fluorescence and X-ray diffraction data in a multivariate analysis approach

Previous studies have shown that the combination of X-ray fluorescence and X-ray diffraction data can be used as a histopathological characterization tool for breast tissue. Recent advances in energy-dispersive X-ray fluorescence techniques have allowed for benchtop systems to produce useful results in a reasonable time frame, allowing for clinical implementation to be realized. Using a polarized energy-dispersive X-ray fluorescence and energy-dispersive X-ray diffraction system optimized for measuring soft tissues, 38 breast tissue samples (19 normal and 19 diseased) were interrogated. The measured elemental concentrations and adipose and fibrous tissue contents were used in a principal component analysis study to determine the variables that produced the most differentiation between the normal and diseased tissues. For each sample, a soft independent modeling of class analogy technique was utilized to create classification models using the K, Fe, and Zn concentration and adipose and fibrous tissue content of all other breast samples. The class model produced from both X-ray fluorescence and X-ray diffraction data correctly classified 31 of 38 samples with no false positives or false negatives, showing improvement from solely X-ray fluorescence models or X-ray diffraction models alone, and demonstrates the usefulness of such a technique.     

基于同步辐射的快速扫描X射线微束荧光成像方法

在上海光源硬X射线微聚焦光束线站(BL15U1)上, 基于EPICS软件平台, 集成运动控制, 光强探测, 荧光探测等功能, 实现了"飞行"模式 (on-the-fly) X射线扫描微束荧光成像方法. 用"飞行"扫描X射线荧光成像法获得了标准镍网, 以及微量元素Cu, Zn,K, Fe在样品老鼠脾内的分布图像, 结果显示该方法不但在速度上有了极大的提高, 而且获得的元素分布图像具有高质量. 关键词： 快速扫描X射线微束荧光成像 同步辐射 微量元素分布     

The beam-based calibration of an X-ray pinhole camera at SSRF

A pinhole camera for imaging X-ray synchrotron radiation from a dipole magnet is now in operation at the Shanghai Synchrotron Radiation Facility (SSRF) storage ring. The electron beam size is derived by unfolding the radiation image and the point spread function (PSF) with deconvolution techniques. The performance of the pinhole is determined by the accuracy of the PSF measurement. This article will focus on a beam-based calibration scheme to measure the PSF system by varying the beam images with different quadrupole settings and fitting them with the corresponding theoretical beam sizes. Applying this method at SSRF, the PSF value of the pinhole is revised from 37 to 44 μm. The deviation in beam size between the theoretical value and the measured value is minimized to 4% after calibration. This optimization allows us to observe the horizontal disturbance due to injection down to as small as 0.5 μm.     

Total reflection X-ray fluorescence spectrometry for quantitative surface and layer analysis

Measurements of X-ray fluorescence spectra versus grazing incident angles provide information on elemental composition as well as density and thickness of near surface layers. Calculations of fluorescence intensities are presented, which are used for the evaluation of data obtained by total reflection X-ray fluorescence (TXRF) spectrometry. The calculation is based on a matrix formalism to account for standing wave phenomena due to transmission and reflection in layered material. For the determination of concentrations the model makes additional use of the fundamental parameter technique in order to include absorption and enhancement effects of the fluorescence radiation. On the basis of experimental data some capabilities of this nondestructive and contactless probing technique are presented.     

标定脉冲星导航探测器的荧光X射线光源

为标定X射线脉冲星导航用探测器, 设计了一种荧光X射线源, 该射线源的工作原理是 用X射线管的出射线轰击特定荧光靶材, 从而获得能量一定的荧光X射线, 并以此作为标定探测器的荧光X射线光源. 采用硅漂移半导体探测器在大气环境下测试了按上述原理搭建的荧光X射线光源的能谱分布和光子流量, 从光子流量入手推算了该荧光X射线光源用于真空系统中对探测器进行标定的可行性. 研制出了荧光X射线光源样机, 并在真空系统中对荧光X射线光源样机光子流量做了测试. 在探测距离D_x=300 cm, X射线管管流I_a=200 μA时, 所测得的荧光X射线光源光子流量可达19.57 ph/s@4.51 keV, 25.22 ph/s@5.41 keV, 33.27 ph/s@8.05 keV, 确认了所提方法的可行性, 获得了标定探测器的荧光X射线光源.     

X-ray nanometer focusing at the SSRF based on a multilayer Laue lens

We designed and fabricated a multilayer Laue lens(MLL) as a hard X-ray focusing device.WSi_2/Si multilayers were chosen owing to their excellent optical properties and relatively sharp interface.The multilayer sample was fabricated by using direct current(DC) magnetron sputtering technology and then was sliced and thinned to form an MLL.The thickness of each layer was determined by scanning electron microscopy(SEM) image analysis with marking layers.The focusing property of the MLL was measured at Beamline 15 U,Shanghai Synchrotron Facility(SSRF).One-dimensional(1D) focusing resolutions of 92 nm are obtained at photon energy of 14 keV.     

A wavelength-dispersive X-ray spectrometer for in/ex situ resonant inelastic X-ray scattering studies

A wavelength-dispersive X-ray spectrometer based on von Hamos geometry for in/ex situ resonant inelastic X-ray scattering (RIXS) studies at BL14W1-X-ray absorption fine structure (XAFS) beamline of Shanghai Synchrotron Radiation Facility (SSRF) is reported. The design considerations and the operational characteristics of the spectrometer are described in detail. With a Si(444) bent crystal, the spectrometer provides an energy range from 8 to 9 keV, which enables the measurement of K-edge X-ray spectroscopy of some transition metal complexes and L-edge X-ray spectroscopy of some 5d transition metal complexes. Based on von Hamos geometry, the process of the collection of RIXS is considerably simplified. The collection of full RIXS planes of tungstic samples requiring spectral resolutions is presented, demonstrating the speciation capabilities of the instrument. Taking the series of oxide-derived copper catalysts for carbon dioxide electrochemical reduction as the research model, the in situ RIXS were measured to probe dynamic changes in electronic structure. Finally, the comparison between in situ RIXS and in situ conventional XAFS is presented, demonstrating more competitive spectral resolution of RIXS.     

Evaluation of full-field energy dispersive X-ray fluorescence imaging apparatus and super resolution analysis with compressed sensing technique

A full-field energy dispersive X-ray fluorescence (FF-EDXRF) imaging spectrometer that utilizes single-photon counting analysis with a charge-coupled device was developed in our laboratory. We evaluated the developed spectrometer with respect to its energy resolution, spatial resolution, quantitative performance, and elemental imaging and compared it with the corresponding characteristics of scanning-type EDXRF spectrometers. In addition, we demonstrate that the limit of detection and sensitivity deteriorate as the analytical area decreases. Finally, compressed sensing, which is a widely used information-processing technique, was applied for clearing XRF images.     

Determination of elements in some lichens growing in Giresun and Ordu province (Turkey) using energy dispersive X-ray fluorescence spectrometry

The concentration of five different elements in six lichens species of different regions in Giresun and Ordu (Turkey) was determined using the energy dispersive X-ray fluorescence method. A radioisotope excited X-ray fluorescence analysis using the method of multiple standard addition is applied to the elemental analysis of lichens. An annular 50 mCi ²⁴¹Am radioactive source and an annular 50 mCi ⁵⁵Fe radioactive source were used for excitation of characteristic K X-rays. An Si(Li)detector which has a 147 eV full-width at half-maximum for 5.9 keV photons was used for intensity measurements. A qualitative analysis of spectral peaks showed that the samples contained potassium, calcium, titanium, iron, and barium.     

Lead speciation of PM2.5 collected from Greater Cairo,Egypt and Zarqa,Jordan: An energy dispersive X-ray fluorescence and X-ray absorption near edge structure study

Fine aerosol particles with an aerodynamic diameter equal or less than 2.5 μm (PM_2.5) have been collected from two sites (residential and industrial) in Greater Cairo, Egypt and one site in Zarqa, Jordan. Based on the elemental quantitative analysis of PM_2.5 using energy dispersive X-ray fluorescence with Mo secondary target, Pb concentrations increased remarkably during winter season regardless of the sampling location. Moreover, it reached the maximum concentration at the industrial location of Greater Cairo, Egypt, and it equals 415 ± 485 ng/m³. The remarkable high standard deviation is due to the significant variation of Pb concentration from time to time during that winter season. Depending on the energy dispersive X-ray fluorescence results, specific PM_2.5 samples that have the highest concentration of Pb (two samples/location) have been selected for the X-ray absorption near edge structure measurements to estimate the oxidation state of Pb species. The X-ray absorption near edge structure measurements including 13 Pb references have been carried out at Pb-L₃ absorption edge (13.039 keV) using fluorescence mode. It was shown that PM_2.5 contains divalent and tetravalent lead in both industrial site in Greater Cairo, Egypt and urban site of Zarqa, Jordan although that of a residential area of Greater Cairo-Egypt is almost divalent lead.     

Development of an online X-ray fluorescence analysis system for heavy metals measurement in cement raw meal

ABSTRACT

Particulate matters, gaseous chemicals, and heavy metals emitted from industrial processes into the environment could be directly transmitted to humans through air inhalation. In order to accurately estimate health risk and control the source of pollution caused by cement raw meal, an online X-ray fluorescence analyzer system, consisting of an X-ray fluorescence analyzer with data acquisition software and a laser rangefinder, was developed to carry out the measurement of heavy metals in cement raw meal. The X-ray fluorescence analyzer was mounted on a sled, which can effectively smooth the surface of cement raw meal and reduce the impact of surface roughness during online measurement. The laser rangefinder was mounted over the sled for measuring the distance between cement raw meal sample and the analyzer. Several heavy metals and other elements in cement raw meal were online measured by the X-ray fluorescence analyzer directly above a conveyor belt. The limits of detection for Pb, Cr, Fe, Ti, Ca, and S by the analyzer were 47 ± 1, 33 ± 1, 37 ± 1, 44 ± 1, 246 ± 4, and 118 ± 1 mg kg^?1, respectively. The relative standard deviation (RSD) for the elements mentioned was less than 10.7%. By comparison with the results by inductively coupled plasma mass spectrometry (ICP-MS) and CHNS/O elemental analyzer, relative deviation (D) of the online X-ray fluorescence analyzer was less than 7.4% for Fe, Ti, Ca, and S, between 1.71% and 12.10% for Pb and Cr.     

Energy-dispersive X-ray fluorescence study of elemental uptake in cauliflower

A ¹⁰⁹Cd radioisotope-induced energy-dispersive X-ray fluorescence (EDXRF) study has been performed on samples of cauliflower consisting of the flower, the leaves and the associated root soil. The cauliflowers were collected from farms near the main dumping site of municipal solid waste in the city of Kolkata, India and also from uncontaminated farms about 50 km away from the city. A unified calibration approach was undertaken for the elemental analysis of the samples of widely varying matrices. The present study suggests that the elemental concentrations in the root soils and leaves of the samples vary from farm to farm, whereby the concentrations of Cu, Zn and Pb in root soils of MSW-contaminated farms are higher by almost an order of magnitude compared to uncontaminated farms. But, the most notable feature of this study is the strikingly similar elemental concentrations in the edible flower part of all samples irrespective of the type of soil.     

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）以及用于三维无损分析的同步辐射X射线荧光扫描和成像方法（如X射线荧光CT、X射线荧光全场成像、共聚焦X射线荧光和掠出射X射线荧光等）。X射线荧光光谱法通过测量元素的特征X射线发射波长或能量,识别元素,该方法首先通过测量发射的特征线强度,然后将该强度与元素浓度联系起来,对给定元素进行量化分析。X射线荧光光谱技术可以进行多元素同时分析,同步辐射X射线荧光谱亮度高,可调谐,相干性、准直性及偏振性好,可以用于分析样品元素的含量和空间分布。近些年来随着新光源技术的使用、分析软件的更新换代和定量分析方法的发展,对同步X射线荧光光谱分析产生了极大促进,采用新型X射线光学元件和探测器,能极大提升分辨率和探测效率,促进相关学科应用的发展。介绍了近几年来国内外同步辐射X射线荧光光谱分析技术及其应用发展状况,给出了国内外比较典型的同步辐射X射线荧光光谱分析光束线站最新技术方面的发展概况,并列举了一些典型应用成果,例如在生物医学、环境科学、地质考古、材料科学和物理及化学等领域的应用。对于本领域及相关领域的专家学者了解国内外同步辐射技术发展现状、应用研究成果具有一定的参考意义。