Electron probe microanalyzer

D. E. Newbury, C. E. Fiori, R. B. Marinenko, R. L. Myklebust, C. R. Swyt, and D. S. Bright. Compositional Mapping with the Electron Probe Microanalyzer. Anal. Ghent. 1990, 62, Parti, 1159A PartII, 1245A. 

In electron-optical instruments, e.g. the scanning electron microscope (SEM), the electron-probe microanalyzer (EPMA), and the transmission electron microscope there is always a wealth of signals, caused by the interaction between the primary electrons and the target, which can be used for materials characterization via imaging, diffraction, and chemical analysis. The different interaction processes for an electron-transparent crystalline specimen inside a TEM are sketched in Eig. 2.31. 

Electron-phonon interaction, 23 804 Electron probe microanalyzer (EPMA), 16 484, 488... 

Optical examination of etched polished surfaces or small particles can often identify compounds or different minerals hy shape, color, optical properties, and the response to various etching attempts. A semi-quantitative elemental analysis can he used for elements with atomic number greater than four by SEM equipped with X-ray fluorescence and various electron detectors. The electron probe microanalyzer and Auer microprobe also provide elemental analysis of small areas. The secondary ion mass spectroscope, laser microprobe mass analyzer, and Raman microprobe analyzer can identify elements, compounds, and molecules. Electron diffraction patterns can be obtained with the TEM to determine which crystalline compounds are present. Ferrography is used for the identification of wear particles in lubricating oils. 

Qualitative analysis of purified CNM was made on the electron probe microanalyzer Camebax with the wide wavelength range (from lA to 20A) with the use of the analyzer crystals PET, TAP and LIF (Fig. 6). The x-ray diffraction research was made on the diffractometer Geigerflex with radiation X=1.789 A and with a step 0,01 grad (Fig. 7). 

Polished embedded in epoxy samples were analyzed by Camebax SX-50 electron probe microanalyzer. Element mapping were recorded by means of WDX-spectrometer with the Ep = 15 kV from the area 512 x 512 /[Pg.219]

Althoi there are several other sprecial types of electron microscopes, perhaps the most valuable is the electron-probe microanalyzer, which allows a researcher to make a chemical analysis of the compositicn of materials. This type of microscope uses the incident electron beam to excite the eitrrsant of characteristic x radiatinr by the various elements composing the qrecimen. Spectrometers built into the instrument detect and analyze the x rays. Viewing the resulting image, the researcher can easily correlate the structure and composition of the material. 

Several plagioclasc grains from annealed samples as well as shock-loaded run products were embedded in epoxy resin and polished. Observation was performed with an optical microscope using reflected and transmitted light Major and minor element compositions were determined by an electron probe microanalyzer. Shock textures were also examined in detail with a scanning electron microscope using back-scattered electron images. 

Electron excitation. The sample is bombarded with high-speed electrons in an evacuated apparatus. Historically, this was the first method and was used by Moseley in his work on the relation between characteristic wavelength and atomic number. It is not a practical method for the rapid analysis of many samples, because the apparatus must be evacuated after the insertion of each sample. However, x-ray spectrometers with electron excitation are used in certain instruments of a research nature in the electron probe microanalyzer (Sec. 15-11) and, as an optional accessory, in the transmission electron microscope and the scanning... 

Diffusion was promoted by heating the samples in a vacuum of about 6.5X10 Pa at 2000 2300 K in order to form a composition gradient between the molybdenum substrate and the rhenium layer. The composition gradient was investigated using an electron probe microanalyzer (EPMA). 

The compositions of both matrix powders pyrolyzed at different temperatures and composites were characterized by XRD. Mechanical properties of composites were measured by three-point-bending tests with 5mmx2mmx40mm specimens in an lnstron-5566 machine, operated at a crosshead speed of 0.5mm/min and a span of 24mm. The microstructures of composites both with and without boron were observed by electron probe microanalyzer (EPMA, JXA-8IOO, JEOL, Tokyo, Japan). 

A beam of electrons striking a target results in the emission of characteristic X-rays. This is the basis of the X-ray tube, as was discussed earlier in the chapter. A beam of electrons striking a sample will also generate characteristic X-rays from the sample. The use of a small diameter electron beam, on the order of 0.1 -1.0 p,m, to excite a sample is the basis of electron probe microanalysis. An electron probe microanalyzer is an X-ray emission spectrometer. The small diameter electron beam excites an area of the surface of the sample that is about 1 pm in diameter. Elemental composition and variation of composition on a microscopic scale can be obtained. 

The electron probe microanalyzer (EM or EPMA) uses a beam of high-energy electrons to bombard the surface of a solid sample. This results, as we have already seen, in the removal of an inner shell electron. As discussed in Section 14.2, this can result in the ejection of a photoelectron (the basis of ESCA) and the emission of an X-ray photon. The X-ray photons emitted have wavelengths characterishc of the elements present. The EPMA uses either a wavelength dispersive (WD) or energy dispersive (ED) X-ray spectrometer to detect and identify the emitted X-rays. This is very much analogous to XRE spectrometry... 

Electron Probe Microanalyzer, An Introduction to, and Its Application to Biochemistry (Andersen). 

The release of trace elements, associated with the combustion of coal, to the environment and disposal of coal ash, which often contains a wide range of trace elements, has become a matter of concern. The determination of these elements in coal (and coke) ash is a very important aspect of coal analysis and involves the use of atomic absorption (ASTM, 2011x). The methods cover the determination of beryllium, chromium, copper, manganese, nickel, lead, vanadium, and zinc. The use of x-ray fluorescence (Prather et al 1979), the electron probe microanalyzer (Raymond and Gooley, 1979), for determination of trace elements in coal has also been reported. 

In several papers (Arvanitoyannis et al. 1997, Chuang et al. 1999, Koyano et al. 2000, Yang et al. 2004), however, the two polymers have been reported to be essentially immiscible. They reported the difficult compatibility by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared spectrum (FUR), electron-probe microanalyzer, etc. Among them, Koyano et al. (2000) pointed out that the chitosan content is dependent upon the position of the film and chitosan is concentrated on the air-surface side of the films. In another research, however, Arvanitoyannis et al. (1997) reported that the difficulty could be mitigated by adding sorbitol and sucrose as plasticizer. 

For quantitative X-ray analysis, electron probe microanalyzers (EPMA, EPA, or EMMA) are able to determine the elemental concentration by X-ray emission from the microvolume of paint samples where a static electron beam interacts. However, due to inhomogeneity of paint samples nonquantitative... 

The earliest commercially available X-ray spectrometer appeared on the market in 1938. Ten years later, Friedman and Birks built the prototype of the first commercial X-ray secondary emission instrument. Somewhat later, Castaing and Guinier built the first electron probe microanalyzer using a focused electron beam to induce X-ray emission of the elements present in microscopic samples using electron probe X-ray microanalysis (EPXMA). The use of protons in PIXE for chemical analysis was first demonstrated by Sterk in 1964. From the 1960s until the present day, the use of large-particle accelerators (synchrotron rings) has resulted in a dramatic... 

Examination of a thin section of oxidized PAN by an electron probe microanalyzer for O2 has revealed that the outer brown core was oxidized and relatively rich in O2 as compared to the inner yellow core [189]. 

Wittry, David B. (1958). Electron Probe Microanalyzer, US Patent No 2916621, Washington, DC U.S. Patent and Trademark Office. 

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