Spectroscopy wavelength dispersive X-ray

Wavelength Dispersive (X-Ray) Spectroscopy Wavelength Dispersive X-Ray Spectroscopy... 

The wavelength-dispersive x-ray spectroscopy method (ASTM D6376) provides a rapid means of measuring metallic elements in coke and provides a guide for determining conformance to material specifications. A benefit of this method is that the sulfur content can also be used to evaluate potential formation of sulfur oxides, a source of atmospheric pollution. This test method specifically determines sodium, aluminum, silicon, sulfur, calcium, titanium, vanadium, manganese, iron, and nickel. 

Materials are made up of chemical compounds that in turn are formed by atoms. Atoms have essentially a dense nucleus around which a cloud of electrons balances the electrical charge of the nucleus. If high-energy electrons are shot at matter, some will bounce off the surface, some will penetrate into it producing X-rays, while others will interact with the higher energy electrons (inner shell electrons) of the atoms. These are the principles used for SEM, EDS and wavelength dispersive X-ray spectroscopy (WDS). 

Wavelength dispersive X-ray spectroscopy (WDS) uses the reflection of X-rays off of a crystal at a characteristic angle to detect X-rays of specific wavelength. 

Wavelength dispersive X-ray spectroscopy (WDS) may extend the threshold of detection by at least an order of magnitude as compared to the energy dispersive X-ray spectroscopy. Since the L X-ray spectra produced by heavier ions displays more complicated structure due to multiple vacancy production (Kageyama et al. 1996), WDS is must for analysis of such complex spectra. However, WDS requires optically flat, stable specimens and is limited to bulk analysis modes, limiting spatial resolution to more than 0.5 o.m. 

Microscopy techniques can be used to evaluate the size and distribution of particles added to polymer fibers, such as metals that modify the physical, mechanical, or electrical properties. In general, ultrathin sections are examined in either STEM or TEM modes to reveal the particles within the polymer. Energy (EDS) and wavelength dispersive x-ray spectroscopy (WDS) methods are used to map for various elements in order to establish the relation between the particle morphology and chemical composition. A specimen preparation method for x-ray analysis in the SEM is to use a trimmed block face, which remains after cutting thin sections, or to study a thick section. An example of such a study is described below. 

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