Bruker D8衍射仪上PANalytical X光管焦斑的调整

X光管是X射线衍射仪的核心元件之一,但其价格昂贵且易老化,不同厂家生产的X光管规格又不尽相同,这给仪器的维修带来较大困难,寻找可替代光管及加深对其认识具有重要的现实意义和应用价值。本文在Bruker D8 ADVANCE型X射线粉末衍射仪上,采用PANalytical公司生产的X-ray陶瓷光管代替其原配光管,在对光管底盖做了适当的调整,使光管和底盖间错位90o后,X光路由点焦斑转变为线焦斑,发现仪器的灵敏度较调整前提高一倍,同原配Simens公司生产的陶瓷光管相当。     

获得高质量X射线衍射谱的测试条件优化

本文以德国BRUKER D8系列衍射仪为例,通过仪器的光路校准、选择光学系统参数、选择测量条件参数三方面详细阐述了获得高质量X射线谱的测试条件优化。精准的光路是获得高质量衍射谱图数据的前提,本文将以"三步法"─光管校准、探测器校准及标样校准为例,详细介绍光路的校准步骤。同时,本文详细介绍了光学系统参数的选择,在保证测试准确度的前提下提高测试的分辨率;同时研究了选择不同的发散狭缝和索拉狭缝对峰形及分辨率的影响。最后,以选用五种不同步长参数测试标样为例,就如何选择测量条件参数,提高效率进行分析。该分析表明不同步长值对峰形及分辨率有很大的影响,一般的物相鉴定测试中,步长参数值的选择以半高宽值的1/5到1/4为宜。     

X荧光光谱法测定乙烯裂解汽油加氢催化剂中活性组分的含量

采用人工合成标样，粉末压片法制备样品，使用理论α系数校正各组分之间因吸收－增强效应而产生的基体效应。用RIX3000型X射线荧光光谱仪对DQ－1催化剂中WO3、NiO,TiO2和F进行了测定，方法经标样和实际样品分析验证，测结果与标样值和实际样品推荐值相符，满足了测定DQ－1催化剂中WO3、NiO,TiO2和F的需要。     

微束微区X荧光探针仪的机械系统设计

随着核技术的发展,工业用核仪器已渗透到国民经济的各个领域并取得了显著的经济效益。而核仪器越来越高的测量精度和性能要求同时也对其机械传动及支撑系统提出了更特殊的需求。首次对微束微区X荧光探针的机械系统及其关键技术进行分析,从仪器的高空间分辨率和高能量分辨率的要求出发,详细讨论仪器的三维载物微动平台和X光管系统的支撑及传动系统的机械设计。对X光透镜焦斑的测试实验结果证明了该机械系统的设计达到了仪器性能指标要求。     

能量色散X射线荧光分析法测定石油焦硫含量的研究

通过二次标样法建立了测定石油焦硫含量的能量色散X射线荧光（EDXRF）分析法,与传统的管式炉法相比,该方法具有测定速度快,重复性好,准确度高的优点,为此建立了相应的企业标准,以便在生产中应用。同时考察了样品的粒度、装样深度及水分对测定结果的影响。     

新型X射线粉末衍射仪高级功能应用研究

本文介绍了德国布鲁克公司新一代的X射线粉末衍射仪"D8 ADVANCE with DAVINCI design"的光源、测角仪、光路系统、探测器和应用软件,并对该仪器进行功能开发应用研究。测试表征了介孔材料SBA-15的小角衍射,并与"NanoSTAR X射线小角散射系统"测试的结果进行对比;测试了3种纤维样品的取向度;通过X射线反射(XRR)测定多层膜,并使用Leptos软件进行了拟合,得到了各层膜的厚度、粗糙度及密度;通过测定单晶样品的摇摆曲线来确定单晶样品的晶面;最后简要介绍了对分布函数(Pair Distribution Functions(PDF))的测定及计算。通过对这些非常规的测试及表征,开发了该仪器的功能。     

小型多道波散型X射线荧光光谱仪的研制

介绍一种新研制成功的小型多道波散裂X射线荧光光谱仪，这种仪器采用小功率X光管作激发源，采用对数螺线弯晶进行分光，整机操作由微处理器和PC机控制，具有仪器结构紧凑，环境适应性强，性能价格比好等特点，适用于建材，化工，冶金等行业的生产控制分析。     

三晶体多轴联动同步辐射X射线荧光光谱仪

针对上海光源X射线吸收精细结构光谱仪对灵敏度和分辨率的要求,研制了三晶体多轴同步辐射X射线荧光光谱仪。其采用一台双晶单色器提供实验X射线,用3块凹面晶体构成系统主体色散结构,并在竖直平面内组成相交的罗兰圆实现荧光分析,可实现10°范围内的布拉格角变化。光谱仪通过高精度控制驱动设备使位移平台实现了3块晶体的4轴联动和总台的2轴联动,其中对位移平台的各轴精度达到了单步长移动25nm,可以实现高分辨率的三维扫描工作。编写了探测器的驱动软件,提高了驱动器的测试灵敏度和分辨率。最后,利用国际通用的实验物理控制系统——EPICS(Experiment Physics and Industrial Control System)完成了整个系统软件的设计,实现了系统各部分的精确控制、自动测量、数据分析和结果显示与存储等功能,构成了一套完整的基于同步辐射光源的高精度高分辨率X射线荧光光谱分析系统。采用钴元素作为测试样品进行了分析实验,结果显示:该光谱仪单次测量时间小于1.5s,测试精度达到0.4eV,分辨率为0.1eV。光谱仪可以完成对样品荧光的采集和分析,操作时间、精度、分辨率和重复性等性能指标均优于现有国内、外设备,目前已成功应用于上海光源XAFS线站的各项科学实验中。     

X射线衍射仪样品装调误差分析与校正

使用X射线衍射仪分析样品,测试角度误差的大小影响着分析结果的准确性,而样品装调误差会导致测试角度误差.本文系统分析了样品装调对测试角度误差的影响.结论是,转动误差和偏心误差对测量误差影响较大,一般需要校正;俯仰误差对测量结果影响较小,一般不用校正.实验表明,通过校正样品装调后的转动误差和偏心误差,可以将测量角度随机性误差控制在0.006°(2θ)以内,并将周期厚度为17nm左右的[Mo/Si]多层膜的测试周期厚度精确到0.1nm,为极紫外区高精度膜厚控制提供了保证.     

软X射线界面传输特性及应用研究

对软X射线与界面相互作用的规律进行初步研究,给出了软X射线界面散射的一级近似一般理论推导,从中给出了粗糙界面软X射线的散射传输特性,表明在粗糙表面上软X射线的镜向反射系数,需要做与粗糙度有关的数学修正。作为形式上的一种方法,本文还给出了粗糙表面对软X射线全反射的动力学模型,以及一维软X射线散射测量粗糙度原理。通过实验测量了λ=243Å,256Å时具有超光滑表面的Mo,Si样品之反射率和λ=44.6Å时石英超光滑样品的反射率。采用镀碘化铯的方法,使“真空紫外-软X光反射率计”的可测量短波长从200Å降至10Å.对44.6Å进行了散射测量,可以明显看到软X射线的非正常反射现象;还对积分散射测粗糙度方法进行了初步研究。最后给出了X线聚焦装置的理论公式和设计实例。     

Calibration of instrument and sample parameters for small angle X-ray scattering

A method for calibrating the parameters of a small angle X-ray scattering instrument using the diffraction ring of a standard sample is presented. A generalized geometric model for small angle X-ray scattering was constructed and detailed mathematical derivations presented to solve for the relevant instrument parameters, which were then used to convert two-dimensional small angle X-ray scattering data to standard curves. The method is valid regardless whether the detector photosensitive plane is perpendicular or tilted with respect to the beam. Small angle X-ray scattering was performed using standard calibration samples to validate the methodology.     

A prototype system to measure X-ray absorption spectra for diagnosis in vivo

We presented a new non-destructive test system for recording of X-ray absorption spectra. Its purpose was to investigate X-ray absorption spectral characteristics of organic and inorganic compounds and to explore the potential for biomedical pathological examination in vivo. An X-ray source with a maximum voltage of 80 kV and maximum current of 1 mA was selected for both good penetration and low radiation dose. A cadmium telluride (CdTe) detector was chosen for its wide energy range. Pulse-height analysis of the output of this sensor yielded energy spectra of X-rays that had passed through the sample. We calibrated the sensor with varying X-ray tube voltages and used tungsten X-ray lines to verify its accuracy. Different kinds of powders, aqueous solutions, aluminium alloys, and plastics were used as experimental samples to show their X-ray spectral absorption differences. The instrument had good prospects for further diagnostics combining radiology and tissue optics.     

Characterization study on NIS X-ray beam qualities and its applications

Quality of low and medium energy X-ray beam at the National Institute for Standards (NIS) of Egypt is studied in details in accordance with the recommendations of the Bureau International des Poids et Measures (BIPM) consultative committee for ionizing radiation (CCRI). The Half Value Layer (HVL) at each applied voltage is precisely determined. The setting up for the X-ray tube according to the TRS No. 469 of IAEA is performed. The effective energy of X-ray is determined using Hyper Pure Germanium Detector (HPGD) connected to photon energy spectrometer. The X-ray air Kerma is measured using NIS secondary standard dosimetry system, which is traceable to the SI units through BIPM. A proposed method for non-invasive tube voltage determination by HPGD is performed. Consequently, all X-ray beam quality parameters are extracted and found to be complying with CCRI recommended values for NIS X-ray tube.     

An X-ray Refractometer

A new X-ray refractometer arrangement for investigating the angular and spectral characteristics of refracted radiation in the hard X-ray range is proposed. The refractometer includes two goniometers set along the path of the direct X-ray beam, two crystal analyzers, and three radiation detectors. The maximum distance between the radiation focus and the entrance slit of the second goniometer is 1.4 m. The refractograms of thin-film samples, including a strained C/Si structure, and the dispersion spectrum of an X-ray tube with a copper anode are first measured. A new refractometry technique using sample rocking at a fixed position of the detector device is described. The results of measurements of the refraction rocking curves for fused silica samples and a ZnSe single crystal are presented.     

Soft-X-ray damage to biological samples

X-ray damage to biological samples was investigated in the wavelength region of 2.7–5 nm, which overlaps the so-called 'water window', the wavelength range of 2.4–4.3 nm usually used in X-ray microscopy. Yeast cells and myofibrils were chosen as representatives of whole cell samples and motile protein systems, respectively. The samples were exposed to X-rays using an apparatus composed mainly of a laser-plasma X-ray source, a Wolter mirror condenser, and a sample cell. The yeast cells lost their dye exclusion ability when the X-ray flux was higher than 1 × 10⁶ photons μm⁻², while the myofibrils lost contractility when the X-ray flux was higher than 4 × 10⁵ photons μm⁻². These X-ray fluxes are lower than the flux required for the X-ray microscope observation of biological samples at a resolution higher than that of light microscopes.     

能量色散X射线荧光光谱仪快速测定土壤中Cu、Pb、Zn、Rb、Nb和Th6种元素

直接使用粉末样品,用便携式能量色散X射线荧光光谱仪测定土壤样品中的Cu、、Zn、Pb、Rb、Nb和Th等6种元素。使用土壤、水系沉积物标准样品建立校准曲线,用铑靶Kα线的康普顿散射线作为内标校正基体效应。方法简便、快速、准确。除Th精密度为13%外,各组分分析的精密度(RSD,n=12)均小于6%,完全能满足化探样品测定的要求。     

Quantitative X-ray imaging of labelled molecules in tissues and cells

Using cisplatin as a model system, we have been able to demonstrate the feasibility of studying the cellular and subcellular distribution of a labelled molecule containing a single atom of platinum per molecule in bone marrow. An X-ray imaging system consisting of a microcomputer, a 4pi system and a software package was interfaced with an electron microscope enabling the computer to control the beam movements as well as receive signals from the STEM and EDS X-ray detectors. X-ray imaging is useful for both tissue and samples in which the population of cells is not homogeneous. Imaging permits elemental distributions to be measured throughout the sample and not in just randomly selected areas as previously done in X-ray microanalysis. Images are created for not only the element labelling the molecule of interest but also other specified elements present.
Three types of maps for imaging labelled molecules are compared and discussed. When the original (collected) data are mapped, the elements of interest are obscured by the continuum. The maps calculated using an internal standard give a concentration distribution on the basis of volume (mmol L⁻¹ of packed cells). The maps calculated using the continuum normalization method according to Hall produces concentration distribution on the basis of mass (mmol kg⁻¹ dry weight). By recalculating using the 'Peak' or 'Hall' method the continuum problem is removed yielding quantitative images of the intracellular distribution of labelled molecules present in low concentrations.     

创新设计的K-Alpha电子能谱仪

本文简单介绍新型高性能、一体化结构的K-Alpha型X射线光电子能谱(XPS)仪的主要特点,包括:全自动样品分析能力,先进的样品导航系统和摄像系统,独特的样品照明方式,用专利技术设计的样品荷电自动补偿装置,方便的谱仪自动校准功能,快速的XPS成像分析能力和高质量的深度剖析,紧凑的组装和小巧的体积,以及高性能价格比等等。这些特点相结合不仅简化XPS操作,而且提高XPS谱仪的分析能力和使用效率,满足用户对现代XPS分析的需求。