X-ray Spectrochemical Analysis Research Articles

Possibilities of the Determination of Matrix Elements of High-Purity Glasses of As–Se and As–S Systems by Inductively Coupled Plasma Atomic Emission Spectrometry

Possibilities of inductively coupled plasma atomic emission spectrometry (ICP AES) as an alternative to X-ray spectrochemical analysis are estimated in the determination of matrix elements of glasses of As–Se and As–S systems. Standard solutions were prepared from pure elements As, Se and S. It was shown that the matrix elements of glasses can be determined with an expanded uncertainty of 0.05–0.1 mol %. The results of determinations by ICP AES and X-ray fluorescence spectrometry were compared; and it was found that by the attained performance characteristics, the results of ICP AES are highly competitive with the data of X-ray fluorescence spectrometry, but do not require sets of adequate solid reference samples.

Seventh All-Russia Conference on X-Ray spectrochemical analysis

Seventh All-Russia Conference on X-Ray spectrochemical analysis

Dependence of analytical signal on the concentration of analyte in X-ray spectral analysis

The dependence of the intensity of analytical signals on the element concentrations expressed in weight percentages I(c) and atomic percentages I(a) in X-ray spectrochemical analysis is considered. It was shown that the change-over from the dependence I(a) to the dependence I(c), which took place in the 1950s, had no theoretical grounds, was based on an incorrect application of the concepts of density and Avogadro’s constant, and was accepted because of practical convenience. In the dependence I(c), the calibration characteristics becomes more complex; it requires corrections for matrix effects, even if these effects are absent. Analytical data published in weight percentages and obtained in the analysis of various samples by conventional X-ray fluorescence analysis (XRFA), X-ray radiometric analysis with an energy-dispersive spectrometer, absorption analysis, and electron probe microanalysis are recalculated into atomic percentages. These results and the data obtained by the author in the analysis of alloys and steels demonstrate a correlation between the intensity of characteristic lines and the atomic concentration of the components. If the calibration curve is based on I(a), a linear dependence over a wide range or the entire concentration range is observed in the majority of systems, the number of the necessary reference standard materials sharply decreases (to one), the sensitivity coefficient increases, and the corrections for matrix effects decrease or the necessity for them disappears.

Reporter gene imaging using radiographic contrast from nonradioactive iodide sequestered by the sodium–iodide symporter

The hypothesis that the human sodium-iodide symporter, NIS, can be used to detect NIS expression using standard radiological techniques was tested using adenoviral transduced NIS expression in human tumor xenografts grown in mice and in a naive dog prostate. Nonradioactive iodide was administered systemically to animals that 1-3 days previously had received a local injection of a replication-competent adenovirus expressing NIS under the control of the CMV promoter. The distribution of radiopacity was assessed in mouse tumors using micro-CT and a clinical X-ray machine and in the prostate of an anesthetized dog using a clinical spiral CT. Iodide sequestration and NIS expression were measured using X-ray spectrochemical analysis and fluorescence microscopy, respectively. Radiographic contrast due to NIS gene expression that was observed indicates the technique has potential for use in preclinical rodent tumor studies but probably lacks sensitivity for human use.

The Irkutsk school of x-ray spectrochemical analysis

The Irkutsk school of x-ray spectrochemical analysis

The Irkutsk school of x-ray spectrochemical analysis

The Irkutsk school of x-ray spectrochemical analysis

The Irkutsk school of X-ray spectrochemical analysis

The history of the Irkutsk school of X-ray spectrochemical analysis founded by N.F. Losev is described. The main results of its research are considered.

High-Resolution Spectrochemical Analysis of Columnar Defects Formed in Bi2Sr2CaCu2Ox by Swift Heavy Ion Irradiation

ABSTRACTSingle-crystal specimen of high-temperature superconductor Bi2Sr2CaCu2Ox was irradiated with 3.5 GeV Xe ions at room temperature up to 1.0 × 1011 ion/cm2. Significant enhancement of magnetization by the irradiation was confirmed. The irradiated specimens were studied by using a high-resolution transmission electron microscope with field emission electron gun (FE-TEM), and, also, with an energy dispersive x-ray analyzer (EDS). Columnar defects with diameter of about 6 nm were observed along the incident ion tracks. By nanoscale high-resolution x-ray spectrochemical analysis across the columnar defect, enrichment of Cu and depletion of Bi, Sr and Ca in the columnar defect center, and vice versa in the outskirts of the defect, was found for the first time. Oxygen depletion in the defect, and increased distribution outside of the defect were also found by electron energy loss spectroscopy. This experimental evidence suggests that the columnar defects are formed as a consequence of Coulomb explosion induced by the electronic excitation of the high-energy heavy ions.

Synthesis and Characterization of Potassium Gallate Silicate with the Zeolite LStructure

A Ga analog of zeolite L(Ga-L–D) with a high degree of crystallinity was synthesized in the K2O–Ga2O3–SiO2–H2O system and was characterized by x-ray diffraction, x-ray spectrochemical analysis, and thermal analysis. The results were used to assess the crystallization kinetics of Ga-L–D.

BaZr 0.85Me 0.15O 2.925 (Me=Y, In and Ga): crystal growth, high-resolution transmission electron microscopy, high-temperature X-ray diffraction and neutron scattering experiments

Nanocrystalline BaZr 0.85Me 0.15O 2.925 (Me=Y, In and Ga) and also undoped BaZrO 3 powder samples with crystallite sizes of D vol=7 nm were prepared using a sol–gel-type hydrolysis in microemulsion-provided nanoreactors. High-resolution transmission electron microscopy (HR-TEM) and X-ray spectrochemical analysis were applied to investigate morphological and structural parameters of the nanosized ceramics. The original powder samples consist of agglomerated nanoscaled spherical crystallites with sizes from 5 to 10 nm in diameter. By structure imaging, the cubic phase of BaZrO 3 was recognised. In the case of the yttrium-doped zirconate, by means of local sensitive EDXS measurements, the evidence is found for an enrichment of the dopant ions in the interfaces of the crystallites, i.e. in the grain boundaries. The effect of dopant enrichment in the grain boundaries on proton diffusion was investigated by neutron scattering experiments, measuring a nanocrystalline sample and a microcrystalline sample as reference. In situ high-temperature X-ray crystallite growth studies were performed to check the influence of different dopant radii on crystallite growth.

DXS: Differential absorption x-ray spectroscopy

X-ray spectrochemical analysis, with either energy-dispersive (EDS) or wavelength-dispersive (WDS) systems, is is used extensively by electron microscopists to determine the chemical composition of selected features in a wide variety of specimens. Several decades of development have yielded efficient and rugged detector crystals and goniometer hardware as well as sophisticated, but user-friendly, software for quantitative chemical and image analysis. Nevertheless an alternative system, based on differential x-ray absorption with "balanced" transmission filters (DXS™) has attractive advantages as a simple, low cost, system for qualitative x-ray microanalysis which does not require liquid nitrogen. Computer processing of intensities obviates the former need for impossibly-precise adjustment of filter thickness. However the filter array must be preset for analysis of the elements that are believed to be present for routine work.DXS analysis is based on the abrupt change in x-ray absorption that occurs between particular elements. This is illustrated by the different mass absorption coefficients for Fe and Cr K radiation for a series of filters in increasing atomic number from Ti to Co as shown in Figure 1 (1,2).

Ultratrace analysis by synchrotron radiation

Application of synchrotron radiation excitation to X-ray spectrochemical analysis is discussed. Improvements in sensitivity, nondestructiveness and selectivity are shown for X-ray fluorescence analysis based on various features of a synchrotron radiation light source. Imaging and chemical specification capabilities are explained together with future possibilities by X-ray microbeam analysis.

The Use of Layered Synthetic Microstructures for Quantitative Analysis of Elements: Boron to Magnesium

Layered Synthetic Microstructures (LSMs) were first reported as commercially available diffracting structures for routine x-ray spectrochemical analysis in 1984 (Nicolosi et al.). Innitially, these devices (PX-1 and PX-2) were intended for use as alternatives for Thallium Acid Phthlate (TAP) and Lead Octadeconate (LOD) for improved stability and diffracted intensity. Improvements in the analytical performance of X-Ray Spectrometers for the elements carbon to magnesium has met, and in some cases exceeded, innitial expectations. Having captured the interest of many new possible applications, developments for LSMs with larger 2d-spacing and greater reflectivity have continued.Previous instruments employing LSMs have had difficulty in measuring X-Ray energies below the carbon K-series characteristic. Below the carbon K-edge energy, several significant phenomenon combine to reduce sensitivity. Among these are: 1) Reduced reflectivity of conventional LSMs, 2) Increased absorption at the polypropylene window of the detector, and 3) Greater electronic noise.

SRによる蛍光X線分析の可能性

X-ray fluorescence trace and micro analyses using a synchrotron radiation source are of value in both research and technology. The outstanding properties of SR which serve to enhance the capability of X-ray spectrochemical analysis are the tunability of the energy spectrum, high brightness, and polarization for reduced scattered background. The state of arts and the future capability of this synchrotron radiation excited X-ray fluorescence analysis are presented. Applications of this method to earth science and materials science are also discussed.

Measurements of the Special Distribution Emitted From X-Ray Spectrographic Tubes

The fundamental parameter method for quantitative analysis of composite elements has been a powerful technique for x-ray spectrochemical analysis in which the x-ray intensity and spectral distribution from x-ray spectrographic tubes are the moste ssential factors in the calculating process based on x- ray physics.

Vergleich von Röntgen- und optischer Emissionsspektralanalyse mit der Glimmlampe bei Anwendung auf AgCu-Binärlegierungen

For the binary eutectic system AgCu, calibration curves are established over a large concentration range (0.3–99.7%). These calibration curves are bent in X-ray spectrochemical analysis as well as in optical emission spectral analysis with a glow discharge lamp as a result of matrix effects. Linearization is achieved by the “method of binary ratios.” By making use of this simple calibration method, it is possible to obtain results with high precision and accuracy: the relative S. D. depends on concentration and is approximately 0.05(1− c). Both methods of spectrochemical analysis are therefore suitable (at least for binary systems) for the determination of major and minor constituents.

Bead homogeneity in the fusion technique for x-ray spectrochemical analysis

Bead homogeneity in the fusion technique for x-ray spectrochemical analysis

The X-ray spectrochemical analysis of gallium phosphide layers on germanium substrates

気相成長法でゲルマニウム基板の上にエピタキシャル成長させたリン化ガリウム層の化学的組成を確かめるため,けい光X線分析を行なった.試料は層の厚さが50μm以下,大きさ6mm×6mm程度のものである.分析線としてGaKα線とPKα線を用い,層の厚さは基板のゲルマニウム基板より放射されるGeKα線によって決定した.検量線は質量吸収係数などの基礎的データによって計算法で作成した.けい光X線の強度は分析線の場合はじゅうぶんに厚いリン化ガリウム標準試料における強度との比によって示す.GeKα線の場合にはゲルマニウム板における強度との比によって示す.このように強度比をとることによって共通の定数を打ち消すことができる.PKα線によるリンの分析は1%程度の確かさが考えられる.GaKα線によるガリウムの分析では厚さの誤差が付加されるうえに検量線のこう配がゆるやかであるため,リンの場合より確度は低い.特に基板のゲルマニウムの強調効果が相対的に大きいところの薄い層において,ガリウム濃度を過大に測定する傾向がある.

Über den Einfluß von spektraler und energetischer Auflösung auf das Nachweisvermögen bei der Röntgenspektralanalyse—I: Abhängigkeit der Nachweisgrenzen von den Spektrometerdaten

The limits of detection in X-ray spectrochemical analysis are significantly determined by the properties of the X-ray spectrometer used. In order to describe this influence only a few parameters of the spectrometer are required: the spectral resolution and the reflection factor of the analyzing crystal, the spatial resolution and the transmission factor of the Soller slit, the energy resolution and the quantrum efficiency of the detector, and the resolution of the discriminator. The dependence of detection limits on these parameters is given. For practical applications it is shown how to determine these parameters.

Ferroelectric Tungsten Bronze-Type Crystal Structures. III. Potassium Lithium Niobate K(6−x−y)Li(4+x)Nb(10+y)O30

Ferroelectric K(6−x−y)Li(4+x)Nb(10+y)O30, with x ≃ 0.07, y ≃ 0.23, and a Curie temperature of 613°K, crystallizes with a tungsten bronze-type structure in the tetragonal system. The lattice constants are a = 12.5764 ± 0.0002 and c = 4.0149 ± 0.0001 Å at 298°K. The space group is P4bm. There is one formula per unit cell. The integrated intensities of 6578 structure factors, inside a reciprocal hemisphere of radius (sinθ) / λ = 1.02 Å−1, were measured with PEXRAD. There are 998 symmetry-independent Fmeas significantly above background. Isomorphism with BaxSr(5−x)Nb10O30 allowed the metal atom positions to be deduced. Oxygen atom positions were obtained by Fourier series methods. Refinement of structural parameters by the method of least squares resulted in a final agreement factor R = 0.0401. The structure is generally like that of other tungsten bronzes of formula (A1)2(A2)4C4(B1)2(B2)8O30, with the A1 site occupied by 87% K and 13% Li, the A2 site by 99% K and 1% Li, and the C site by 94% Li and 6% Nb. The B sites are fully occupied by Nb. X-ray spectrochemical analysis and the present diffraction study suggest x ≃ 0.07 and y ≃ 0.23 for the nonstoichiometric formula above. Evidence for major positional disorder, excluding occupancy disorder, similar to that observed in BaxSr(5−x)Nb10O30 and in Ba(4+x)Na(2−2x)Nb10O30 is not present for K(6−x−y)Li(4+x)Nb(10+y)O30. The K/Li atom at the A1 site is 12 coordinated with average K/Li–O distance of 2.833 Å. The K/Li atom at the A2 site is nine coordinated with average K/Li–O distance of 3.024 Å. The Li/Nb atom at the C site has three nearest oxygen neighbors at an average distance of 2.153 Å and six additional next-nearest neighbors at an average distance of 2.542 Å. The two independent irregular NbO6 octahedra have an average Nb–O separation of 1.973 Å. The Nb atom displacements, of 0.167 and 0.160 Å from the nearest mean oxygen plane, may be compared with the value of 0.175 Å predicted from the parabolic relation with Curie temperature. All metal atoms are displaced from the mean planes of oxygen in the same sense, making the positive polarization direction parallel to the sense of this displacement.