Energy-Dispersive Analysis EDS

Energy-Dispersive Analysis (EDS). EDS is the more generally applicable and versatile system for X-ray analysis, and the detector normally consists of a small 

The resistivity of the silicon is increased by making the whole detector a semiconductor p-i-n junction which is reverse biased by a potential applied to a thin film of gold on the outer faces. The silicon is doped with a small concentration of lithium, and the whole detector is cooled to liquid nitrogen temperature (77 K). The current which passes between the (gold) electrodes is now very small until an X-ray enters the detector, and the resultant current pulse can be amplified and measured. 

The gold-coated outer surface is protected by an ultra thin window of polymer which has been coated with evaporated metal in order to minimise light transmission. 

Quantitative Analysis. The efficiency of the detector is such that almost 100% of the X-rays entering it will produce a pulse, but the pulse processing speed limits the rate at which X-rays can be counted. If the count rate is less than a few thousand counts per second, then most of the incoming pulses are processed, but as the count rate rises an increasing fraction of the pulses are rejected. The live time during an analysis when the detector was counting is thus less than the elapsed time, and the EDS system records both times in order that the true count rate may be measured. 

The energy resolution of the detector is relatively poor, so that each X-ray line appears as a broad peak 100-200 eV wide. Any X-ray line thus occupies several channels of the MCA, and so the peak height is reduced. This factor, together with 

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SEM is similarly used with energy-dispersive analysis (EDS) to characterize and analyze structure. EESEM used to determine size and morphology. 

Fig. 6.25 Correlations between characteristic ratios a AFCT versus Si/Al, b Si/Al versus O/T and c Si/CT versus Al/CT, where CT is sum of cations (viz., Na, K", Ca ), T is the sum of Si and A1 and, O is the oxygen atoms present on the crystal surfaces, observed by the energy dispersive analysis, EDS of the micrographs...

Moreover, thin (less than 2 pm thickness) and pinhole-free Pd-Cu alloy composite membranes with a diffusion barrier have been fabricated on mesoporous stainless steel supports (MSSS) by vacuum electro-deposition (Nam and Lee, 2001). The deposition film was fabricated by multilayer coating and diffusion treatment and the formation of Pd-Cu alloys was achieved by annealing the as-deposited membranes at 450°C in nitrogen atmosphere. To improve the structural stability of Pd alloy/Ni-MSSS composite membranes, a thin intermediate layer of silica by sol-gel method was introduced as a diffusion barrier between Pd-Cu active layer and a modified MSSS substrate. The composition and phase structures of the alloy film were studied by energy dispersive analysis (EDS) and XRD the typical Pd-Cu plating had a composition of 63% Pd and 37%Cu and the atomic inter-diffusion of Pd and Cu resulted in Pd-Cu alloys in an fee structure. The electron probe microanalyser (EPMA) profiling analysis indicated that the improved membranes were structurally stable. The Pd-Cu alloy composite membrane obtained in this study yielded excellent separation performance with H2 permeance of 2.5 x 10 cm /(cm cmHg s) and Hj/Nj selectivity above 70000 at 450°C. 

A scanning electron microscope can also be equipped with additional instmmentation for electron-excited x-ray analysis (9). In many systems, this is performed in the mode known as energy dispersive x-ray analysis (edx). Other common acronyms for this method are eds for energy dispersive spectroscopy or edax for energy dispersive analysis of x-rays. 

The incoming electron beam interacts with the sample to produce a number of signals that are subsequently detectable and useful for analysis. They are X-ray emission, which can be detected either by Energy Dispersive Spectroscopy, EDS, or by Wavelength Dispersive Spectroscopy, WDS visible or UV emission, which is known as Cathodoluminescence, CL and Auger Electron Emission, which is the basis of Auger Electron Spectroscopy discussed in Chapter 5. Finally, the incoming... 

In order to confirm the formation of nanodots, the fabricated nanodot arrays on a substrate were examined using energy dispersive spectroscopy (EDS). The EDS analysis of niobium oxide arrays on Si film before etching (Fig. 2(a)) was shown in Fig. 3(a). The Si peak as well as Nb and O peaks was observed because niobium oxide on Si film was so thin. 

TEM observation and elemental analysis of the catalysts were performed by means of a transmission electron microscope (JEOL, JEM-201 OF) with energy dispersion spectrometer (EDS). The surface property of catalysts was analyzed by an X-ray photoelectron spectrometer (JEOL, JPS-90SX) using an A1 Ka radiation (1486.6 eV, 120 W). Carbon Is peak at binding energy of 284.6 eV due to adventitious carbon was used as an internal reference. Temperature programmed oxidation (TPO) with 5 vol.% 02/He was also performed on the catalyst after reaction, and the consumption of O2 was detected by thermal conductivity detector. The temperature was ramped at 10 K min to 1273 K. 

Although a number of secondary minerals have been predicted to form in weathered CCB materials, few have been positively identified by physical characterization methods. Secondary phases in CCB materials may be difficult or impossible to characterize due to their low abundance and small particle size. Conventional mineral identification methods such as X-ray diffraction (XRD) analysis fail to identify secondary phases that are less than 1-5% by weight of the CCB or are X-ray amorphous. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM), coupled with energy dispersive spectroscopy (EDS), can often identify phases not seen by XRD. Additional analytical methods used to characterize trace secondary phases include infrared (IR) spectroscopy, electron microprobe (EMP) analysis, differential thermal analysis (DTA), and various synchrotron radiation techniques (e.g., micro-XRD, X-ray absorption near-eidge spectroscopy [XANES], X-ray absorption fine-structure [XAFSJ). 

X-ray microanalysis techniques— in particular, electron probe x-ray microanalysis (EPXMA or EPMA) and SEM coupled with energy dispersive spectrometers (EDS, EDX) are, by far, one of the surface analysis techniques most extensively used in the field of art and art conservation, and they have actually become routine methods of analyzing art and archaeological objects and monitoring conservation treatments [34, 61, 63]. 

In 2006, a table-top energy-dispersive XRF (ED-XRF) spectrometer was acquired by the Archaeometry Lab to facilitate non-destructive analysis of obsidian and other types of artifacts. One of the first projects performed on the new XRF spectrometer was the re-analysis of the geological samples from sources in Peru. As a result, it is now possible for the Archaeometry Lab to use either XRF or NAA to successfully determine the provenance of obsidian artifacts from Peru. Due to its light weight, the spectrometer also has the potential to be transported from the laboratory to museums and to archaeological sites for in situ analysis. 

Enamel and bone, strontium isotope analysis, 102-104 Energy dispersive spectrometry (EDS), scanning electron microscopy, Seip textiles, 35 Energy dispersive X-ray fluorescence (EDXRF), elemental analyses copper-based coins, 231-245 copper coins, Herodian prutah, 246-257... 

This chapter summarizes results obtained during the past 5 years, on the design, preparation and study of titanium and vanadium compounds as candidate precursors to TiC, TiN, VC, and VN. The study of the precursor molecules was conducted through several steps. After their synthesis, thermoanalytical studies (TG-DTA), coupled to simultaneous mass spectroscopic (MS) analysis of the decomposition gases, were carried out to determine their suitability as precursors. CVD experiments were then conducted and were followed by characterization of the deposits by scanning electron microscopy (SEM) energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and electron microprobe analysis with wavelength dispersion spectroscopy (EPMA-WDS). 

Bulk spectroscopic techniques such as x-ray fluorescence and optical and infrared spectroscopies involve minimal sample preparation beyond cutting and mounting the sample. These are discussed in Section 9.2.1. Spectroscopic techniques such as wavelength dispersive spectroscopy (WDS) and energy dispersive spectroscopy (EDS) are performed inside the SEM and TEM during microscopic analysis. Therefore, the sample preparation concerns there are identical to those for SEM and TEM sample preparation as covered in Section 9.3. Some special requirements are to be met for surface spectroscopic techniques because of the vulnerability of this region. These are outlined in Section 9.5. 

Particle composition is far more difficult to evaluate. Bulk elemental analysis [atomic absorption spectroscopy (AA) or inductively coupled plasma mass spectrometry (ICP-MS) are most common for metals] is useful in confirming the overall bimetallic composition of the sample, but provides no information regarding individual particles. Microscopy techniques, particularly Energy Dispersive Spectroscopy (EDS), has supported the assertion that bimetallic DENs are bimetallic nanoparticles, rather than a physical mixture of monometallics [16]. Provided the particle density is low... 

Characterization. CHNS analysis was carried using the Thermo Finnigan FLASH EA 1112 CHNS analyzer. Energy dispersive analysis of X-rays (EDAX) was carried using the OXFORD ED AX system. Infrared spectroscopic studies of KBr pellets were recorded in the mid-IRregion (Bruker IFS-66v). Thermogravimetric analysis was carried out (Metler-Toledo) in nitrogen atmosphere (flow rate... 

BN nanotubes were prepared by a standard literature procedure.7 BN nanotubes were prepared by the reaction of B2C>3 with multi-walled carbon nanotubes (MWNTs) in the presence of ammonia at 1250 °C for 3 h. A grey spongy product was obtained after the reaction indicating the presence of unreacted MWNTs along with BN nanotubes. The product was washed with hot water to remove excess B2O3. The excess carbon present in the product was removed by oxidation at 800 C in low-pressure air (20 mPa). Scanning electron microscope (SEM) and energy dispersive analysis of X-rays (ED AX) were performed with... 

Energy-dispersive analysis of X-rays was the chosen analytical method because of its sensitivity to elements heavier than sodium, its capability of mapping elemental distribution, and its capacity for combination with a scanning electron microscope. EDS microanalysis has been reported to be suitable for the determination of mordant treatments on historical fibers (8-10) and has been used to characterize metal wrappings of combination yarns (11-13). EDS microanalysis has also been used to determine the composition of pseudomorphs and fibers in the process of mineral replacement (13, 14, 15). 

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