Wavelength-dispersive X-ray analysi

Within this technique, we include EDX (energy dispersive x-ray analysis), WDX (wavelength dispersive x-ray analysis), and XRF (x-ray fluorescence analysis). In all of these, x-rays emitted from a sample are analyzed. In one case, they are created by bombarding the sample with x-rays (XRF), and in the others, they are created by high energy electron beam as in an SEM (EDX, WDX). 

The electron-optical performance of the EPMA system is indistinguishable from that of a conventional scanning electron microscope (SEM) thus, EPMA combines all of the imaging capabilities of a SEM with quantitative elemental analysis using both energy- and wavelength-dispersive X-ray spectrometry. ... 

Examples of using reference samples for calibration can be found in several chapters of the uses Methods for Geochemical Analysis (Baedecker 1987). Solid reference sample powders are used in cahbrating the dc arc emission, energy-dispersive X-ray and instrumental neutron activation analyses described, while acid-dissolved rock reference samples are used for IGP emission analyses and fused reference samples are used for wavelength-dispersive X-ray analyses. 

Taggart JE Jr, Lindsay JR, Scott BA, Vivit DV, Bartel AJ, Stewart K C (1993) Analysis of geological materials by wavelength-dispersive X-ray fluorescence spectrometry. In Badecker PA, ed. U.S. Geological Survey Bulletin 1770. Methods for Geochemical Analysis, pp E1-E19. 

Falcone, R., A. Renier, and M. Verita, M. (2002), Wavelength-dispersive X-ray fluorescence analysis of ancient glasses, Archaeometry 44(4), 531-542. 

Elemental analysis can also be performed on SEM samples using x-ray spectrometer attachments [55], The techniques are known as energy dispersive x-ray (EDX) analysis and wavelength dispersive x-ray (WDX) analysis and require installation of a detector in the sample chamber. 

This non-destructive technique is a very suitable tool for rapid in-line analysis of inorganic additives in food products (Price and Major, 1990 Anon, 1995). It can be readily used by non-skilled operators, and dry materials can be pressed into a pellet or simply poured into a sample cup. The principles of this technique related to food analysis are described by Pomeranz and Meloan (1994). A useful Internet site is http //www.xraysite.com, which includes information about different XRF instruments from various companies. Wavelength dispersive X-ray fluorescence (WD-XRF) or bench-top energy dispersive (ED-XRF) instruments are available. XRF is a comparative technique, thus a calibration curve needs to be established using food products of the same type as those to be... 

TGA/DTA combined thermogravimetry / differential thermal analysis WDX wavelength-dispersive X-ray diffraction... 

D 4927 Elemental Analysis of Lubricant and Additive Components, Barium, Calcium, Phosphorus, Sulfur, and Zinc, by Wavelength Dispersive X-ray Fluorescence Spectroscopy... 

X-ray spectroscopy is nowadays applied mostly in the form of X-ray fluorescence, where scanning monochannel machines, sequence spectrometers and simultaneous spectrometers are used in wavelength dispersive X-ray fluorescence. The introduction of bent analyser-crystals extended the method to smaller samples, thus marking another step toward microprobe analysis. 

A Jeol-35 Scanning Electron Microscope equipped with energy-and wavelength- dispersive X-ray spectrometers was used for elemental analysis. Spot analyses were carried out these covered approximately 0.5 pm for the pyrite and 1 pm for the coal. The standard atomic number, absorption and fluorescence (ZAF) corrections were applied to all analyses, using counting times of 200 seconds, an accelerating voltage of 15 kV and a pyrite crystal as standard. 

Wavelength dispersive X-ray spectrometry (WDS) for a more detailed elemental analysis of samples in the SEM. JEOL Four-Crystal Spectrometer attached to the JSM-35C SEM can be used for l-pm spot analysis, digital and analog line scans, and X-ray image mapping, elements detection from Be to U, minimum detection limit of 0.01% by weight, fully quantitative results by extended cp-p-z. 

Selected neat-theoretical density samples were hot isostatically pressed to full density (1400°C, 180 MPa, 1 h). Compact purity at this stage of processing was assessed using wavelength-dispersive x-ray fluorescence a detection limit of <1 ppm for the impurities of interest is claimed. No loss of purity relative to the starting powder was detected for the undoped material. Chemical analysis of the Ti-doped material indicated a Ti level of =700 ppm, with a factor of two uncertainty. This su ests no substantial Ti loss occurs during firing. 

In the technique of X-ray fluorescence (XRF) characteristic X-ray wavelengths are produced from a solid sample, and may be used to identify elements present (see Topic A4). The method is less accurate than those based on the atomic spectra of gases, but is useful for solid samples, especially minerals that may contain many elements. X-rays may be excited by the electron beam in an electron microscope, and the resulting energy dispersive X-ray analysis (EDAX) can be used to give approximate atomic analyses of individual grains of a powdered solid and to estimate the chemical homogeneity of a sample. 

In this analysis, three wavelength-dispersive X-ray spectrometers were used to simultaneously measure the characteristic X-ray intensities for copper, barium, and yttrium, at each point in the scan, producing two-dimensional X-ray intensity arrays. Complete quantitative analysis corrections, using the NBS theoretical matrix correction procedure FRAME (2), were performed at each picture element (pixel) in the image scan. 

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