X-Ray Nanoanalysis in the SEM

2005 ◽  
Author(s):  
William E. Vanderlinde ◽  
Don Chernoff
Keyword(s):  
Computer Software ◽  
Energy Dispersive ◽  
Bulk Analysis ◽  
Thin Sections ◽  
X Ray ◽  
Interaction Volume ◽  
Surface Sensitivity ◽  
Analysis Technique ◽  
Environmental Sem ◽  
Volume Size

Abstract Scanning electron microscopy (SEM)/energy dispersive x-ray spectroscopy (EDS) is generally thought of as a bulk analysis technique that is not suited for nano-scale analysis. This paper discusses several options for reducing or eliminating the interaction volume size and obtaining x-ray data with much higher spatial resolution and surface sensitivity than is typically achieved in the SEM. These include collecting data at very low accelerating voltages to minimize beam spread in the sample, tilting the sample to keep the interaction volume near the surface, and analyzing thin sections to reduce or eliminate the problem of beam spread in the sample. Computer software simulations, in conjunction with experimental data are used to illustrate these methods. The paper also discusses issues effecting EDS analysis in the environmental SEM. It has been shown that computer modeling is a useful tool for determining the optimum beam conditions to improve energy dispersive analysis in the SEM.

about chemical bonding and molecular structure. This information can be used to detect th e types of organic materials present on the surface. 4.3.2.2. Raman spectroscopy (RS) [7, 8] It is used to examine the energy levels of molecules that cannot be well character-ized via infrared spectroscopy. Th e two techniques, however, are complimentary. In the RS, a sample is irradiated with a strong monochromatic light source (usu-ally a laser). Most of the radiation will scatter or "reflect off' the sample at the same energy as the incoming laser radiation. However, a small amount will scat-ter from the sample at a wavelength slightly shifted from the original wavelength. It is possible to study the molecular structure or determine the chemical identity of the sample. It is quite straightforward to identify compounds by spectral library search. Due to extensive library spectral information, the unique spectral finger-print of every compound, and the ease with which such analyses can be per-formed, the RS is a very useful technique for various applications. An important application of the RS is the rapid, nondestructive characterization of diamond, diamond-like, and amorphous-carbon films. 4.3.2.3. Scanning electron microscopy (SEM) / energy dispersive X-ra y analysis (EDX) [7, 8] The SEM produce s detailed photographs that provide important information about the surface structure and morphology of almost any kind of sample. Image analy-sis is often the first and most important step in problem solving and failure analy-sis. With SEM, a focused beam of high-energy electrons is scanned over the sur-face of a material, causing a variety of signals, secondary electrons, X-rays, photons, etc. - each of which may be used to characterize the material with re-spect to specific properties . The signals are used to modulate the brightness on a CRT display, thereb y providing a high-resolution map of the selected material property. It is a surface imaging technique, but with Energy Dispersive X-ray (EDX) it can identify elements in the near-surface region. This technique is most useful for imaging particles. 4.3.2.4. X-ray fluorescence (XRF) [7, 8] Incident X-rays are used to excite surface atoms. The atoms relax through the emission of an X-ray with energy characteristic of the parent atoms and the inten-sity proportional to the amount of the element present. It is a bulk or "total mate-rials" characterization technique for rapid, simultaneous, and nondestructive analysis of elements having an atomic number higher than that of boron. Tradi-tional bulk analysis applications include identifying metals and alloys, detecting trace elements in liquids, and identifying residues and deposits. 4.3.2.5. Total-reflection X-ray fluorescence (TXRF) [7, 8] It is a special XRF technique that provides extremely sensitive measures of the elements present in a material's outer surface. Applications include searching for metal contamination in thin films on silicon wafers and detecting picogram-levels o f arsenic, lead, mercury and cadmium on hazardous, chemical fume hoods.

2003 ◽  
pp. 43-45
Keyword(s):  
Molecular Structure ◽  
Energy Levels ◽  
Monochromatic Light ◽  
Surface Region ◽  
Carbon Films ◽  
Energy Dispersive ◽  
X Rays ◽  
Bulk Analysis ◽  
X Ray ◽  
High Resolution Map

scholarly journals On the calculation of the gauge volume size for energy-dispersive X-ray diffraction. Erratum

2011 ◽  
Vol 19 (1) ◽  
pp. 136-136
Author(s):  
Matthew R. Rowles
Keyword(s):  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gauge Volume ◽  
Volume Size

An equation in the paper by Rowles [(2011),J. Synchrotron Rad.18, 938–941] is corrected.

A background correction for energy-dispersive X-ray analysis of thin sections

1977 ◽  
Vol 6 (3) ◽  
pp. 154-160 ◽  
Author(s):  
William M. Sherry ◽  
John B. Vander Sande
Keyword(s):  
Background Correction ◽  
Energy Dispersive ◽  
Thin Sections ◽  
X Ray

Energy-dispersive X-ray analysis on thin sections and unimpregnated soil material.

1975 ◽  
Vol 23 (2) ◽  
pp. 113-125
Author(s):  
E.B.A. Bisdom ◽  
S. Henstra ◽  
A. Jongerius ◽  
F. Thiel
Keyword(s):  
Chemical Elements ◽  
Research Abstract ◽  
Energy Dispersive ◽  
Topographic Image ◽  
Thin Sections ◽  
Soil Material ◽  
Crystalline Materials ◽  
X Ray ◽  
Loose Soil

A combination of scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDXRA) was used in the study of soil materials. The investigation in situ of components in thin sections was used to estimate chemical elements with atomic numbers 11 upwards, from sodium on. EDXRA could detect chemical elements up to magnifications of X 10 000. The composition of amorphous and micro-crystalline materials cannot be estimated in thin sections by light microscopy but by this technique was clearly displayed. Composition of loose soil material can also be investigated. The material that could be studied by SEM-EDXRA did not need high polishing of the thin section, and the plastic used for impregnation of the soil material was not affected by the investigation.Identification of chemical elements in situ, high resolution of the topographic image and relatively short testing times for the elements make this combination of techniques useful for soil research. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals On the calculation of the gauge volume size for energy-dispersive X-ray diffraction

2011 ◽  
Vol 18 (6) ◽  
pp. 938-941 ◽  
Author(s):  
Matthew R. Rowles
Keyword(s):  
Energy Dispersive ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
Active Volume ◽  
X Ray ◽  
Gauge Volume ◽  
Energy Dispersive Diffraction ◽  
Volume Size

Equations for the calculation of the dimensions of a gauge volume, also known as the active volume or diffraction lozenge, in an energy-dispersive diffraction experiment where the detector is collimated by two ideal slits have been developed. Equations are given for equatorially divergent and parallel incident X-ray beams, assuming negligible axial divergence.

Energy-Dispersive X-Ray Techniques for Accurate Heavy Element Assay

1986 ◽  
Vol 30 ◽  
pp. 285-292 ◽  
Author(s):  
H. Ottmar ◽  
H. Eberle ◽  
P. Matussek ◽  
I. Michel-Piper
Keyword(s):  
Absorption Edge ◽  
Heavy Element ◽  
Accurate Determination ◽  
Energy Dispersive ◽  
X Rays ◽  
Specific Absorption ◽  
X Ray ◽  
Xrf Analysis ◽  
Analysis Technique

Energy-dispersive X-ray techniques can be employed in two different ways for the accurate determination of element concentrations in specimens: (1) spectrometry of fluoresced characteristic X-rays as widely applied in the various modes of the traditional XRF analysis technique, and (2) spectrometry of the energy-differential transmittance of an X-ray continuum at the element-specific absorption-edge energies.

Thin sectioning, freeze fracturing, energy dispersive x-ray analysis, and chemical analysis in the study of inclusions in seed protein bodies: almond, Brazil nut, and quandong

1978 ◽  
Vol 56 (17) ◽  
pp. 2050-2061 ◽  
Author(s):  
John N. A. Lott ◽  
Mark S. Buttrose
Keyword(s):  
Chemical Analysis ◽  
Freeze Fracture ◽  
Prunus Dulcis ◽  
Energy Dispersive ◽  
Protein Bodies ◽  
Brazil Nut ◽  
Fixed Tissue ◽  
Thin Sections ◽  
X Ray ◽  
Freeze Dried

Protein bodies from almond (Prunus dulcis), Brazil nut (Bertholletia excelsa), and quandong (Santalum acuminatum) have been studied in thin sections of fixed and embedded tissue, in freeze-fracture replicas of unfixed tissue, by chemical analysis of tissue for P, K, Mg, and Ca, and by energy dispersive x-ray (EDX) analysis of both sections of glutaraldehyde-fixed tissue and freeze-dried tissue powders. The protein bodies in all three species contained globoid crystals, protein crystalloids, and proteinaceous matrix regions. Results of EDX analyses were consistent with globoid crystals being rich in phytin. Variation in both the structure and the elemental composition of globoids was common. In almond some globoids were lobed rather than spherical, and large globoid crystals often contained considerable calcium whereas small globoid crystals contained little if any calcium. The globoid crystals of Brazil nut often contained barium in addition to P, K, Ca, and Mg. Protein crystalloids of Brazil nut were compound crystals. Protein bodies of quandong seed, which is largely endosperm rather than embryo, were unexceptional.

scholarly journals Interaction of Glass-ionomer Cements with Moist Dentin

2004 ◽  
Vol 83 (4) ◽  
pp. 283-289 ◽  
Author(s):  
C.K.Y. Yiu ◽  
F.R. Tay ◽  
N.M. King ◽  
D.H. Pashley ◽  
S.K. Sidhu ◽  
...  
Keyword(s):  
Field Emission ◽  
Energy Dispersive ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Air Voids ◽  
X Ray ◽  
Water Permeation ◽  
Aqueous Gels ◽  
Glass Fillers ◽  
Environmental Sem

Glass-ionomer cements (GICs) are regarded as aqueous gels made up of polyalkenoic acid salts containing ion-leachable glass fillers. The consequence of water permeation across the GIC-dentin interface is unknown. This study used SEM, field-emission/environmental SEM (FE-ESEM), and TEM to examine the ultrastructure of GIC-bonded moist dentin. Dentin surfaces bonded with 6 auto-cured GICs were examined along the fractured GIC-dentin interfaces. Additional specimens fractured 3 mm away from the interfaces were used as controls. SEM revealed spherical bodies along GIC-dentin interfaces that resembled hollow eggshells. FE-SEM depicted similar bodies with additional solid cores. Energy-dispersive x-ray analysis and TEM showed that the spherical bodies consisted of a silicon-rich GIC phase that was absent from the air-voids in the controls. The GIC inclusions near dentin surfaces result from a continuation of the GI reaction, within air-voids of the original polyalkenoate matrix, that occurred upon water diffusion from moist dentin.

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