Routine use of a second-generation windowless detector for energy-dispersive ultra-light element X-ray analysis

The phenomena of escape peaks is well known, but caution must be exercised to avoid confusion in peak identification. A summary of our experiences with certain escape peaks may be useful to others.In biomedical devices, metal components are often used in pure elemental form or as alloys with high concentrations of a particular element. Noble metals such as gold, platinum and iridium are commonly used in pacemaker components. These metals are body compatible, have high corrosion resistance and are good electrical conductors. Pacemaker electrodes are commonly made of platinum, used alone or alloyed with about 10% iridium. These materials are routinely analyzed using the scanning electron microscope (SEM) with energy-dispersive x-ray spectroscopy (EDS).While analyzing platinum electrodes at 20 keV with the Beryllium window open, it was noted that an unexpected peak was seen in the spectrum near where carbon would be expected at 0.310 keV. The same peak was noted when the Be window was closed (figure 1). It was first thought to be a detector problem.

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Do Ultra-Thin Polymer X-Ray Windows Leak Water Vapor?

Microscopy and Microanalysis ◽

10.1017/s1431927600016263 ◽

1999 ◽

Vol 5 (S2) ◽

pp. 588-589

Author(s):

A. Nielson ◽

J. Thorne

Keyword(s):

Water Vapor ◽

Thin Layer ◽

Liquid Nitrogen ◽

Energy Dispersive Spectroscopy ◽

Light Element ◽

Energy Dispersive ◽

Nitrogen Form ◽

X Ray ◽

The Past ◽

Thin Polymer

Ultra-thin polymer x-ray windows have been developed for energy dispersive spectroscopy (EDS) that enable analysis of the elements lighter in mass than sodium while protecting the detector from light and gases. Windowless detectors produce the ultimate in detector sensitivity, however that sensitivity is lost when ice and other contaminants form on the detector. Polymer windows have had a problem with icing in the past, however modern ultra-thin polymer windows contain metalized layers to prevent the diffusion of water. Nevertheless, over the course of time it has been observed that some detectors with polymer windows that are kept continually cool with liquid nitrogen form a thin layer of ice that attenuates light element sensitivity. The source of this water has been hypothesized to be a gradual leak of water vapor through the polymer x-ray window. This hypothesis has been questioned on the basis that the windows were helium leak tight to 1 x 10−9 mbar L/sec and helium is a smaller molecule than water.

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Enhancement of Low Energy / Light Element Energy Dispersive Analysis in the Scanning Electron Microscope Using a Non-Focusing X-Ray Optic

Microscopy and Microanalysis ◽

10.1017/s1431927609095427 ◽

2009 ◽

Vol 15 (S2) ◽

pp. 218-219

Author(s):

RE Edelmann ◽

V Vasudevan ◽

D Kohls ◽

J Ullmer

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Light Element ◽

Low Energy ◽

Energy Dispersive ◽

Energy Dispersive Analysis ◽

X Ray ◽

Dispersive Analysis ◽

Scanning Electron

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

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Light Element Abundance in Brain Nuclei Using Energy Dispersive X-Ray Analysis and Atomic Absorption Spectrophotometry

Neurological Research ◽

10.1080/01616412.1980.11739565 ◽

1980 ◽

Vol 1 (4) ◽

pp. 341-348 ◽

Cited By ~ 1

Author(s):

Ronald J. Ignelzi ◽

M. Gary Wickham

Keyword(s):

Atomic Absorption ◽

Light Element ◽

Atomic Absorption Spectrophotometry ◽

Energy Dispersive ◽

Element Abundance ◽

Brain Nuclei ◽

X Ray ◽

Absorption Spectrophotometry ◽

Light Element Abundance

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A Generalized Matrix Correction Approach for Energy-Dispersive X-Ray Fluorescence Analysis of Paint Using Fundamental Parameters and Scattered Silver Kα Peaks

Advances in X-ray Analysis ◽

10.1154/s0376030800012726 ◽

1982 ◽

Vol 26 ◽

pp. 377-384

Author(s):

Leif Højslet Christensen ◽

Iver Drabæk

Keyword(s):

Light Element ◽

Direct Determination ◽

Fluorescence Analysis ◽

Bulk Sample ◽

Energy Dispersive ◽

Limiting Factor ◽

X Ray ◽

Fundamental Parameters ◽

Relative Standard ◽

Generalized Matrix

AbstractAn energy-dispersive x-ray fluorescence method has been developed for the direct determination of major and minor elements in infinitely thick samples of paint. Matrix absorption and enhancement corrections are iteratively calculated from a knowledge of tabulated fundamental parameters and the unknown weight fractions. An estimate of the significant light element fraction of the bulk sample required for the calculation of matrix attenuation is obtained using the scatter peaks of the silver secondary target. Relative elemental calibration constants and calibration factors for the coherent and incoherent peaks are determined experimentally using either thin-film standards or standards of known total composition. For routine analysis only one absolute standard is required. The method has been applied to different types of paint with a relative standard deviation better than 5% provided the counting statistics are not the limiting factor. The accuracy has been tested by comparing own results with those obtained either from the formulation or from, instrumental neutron activation analysis.

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Microanalysis of precipitates in a ferritic steel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110234 ◽

1978 ◽

Vol 36 (1) ◽

pp. 618-619

Author(s):

J.M. Titchmarsh

Keyword(s):

Ferritic Steel ◽

Particle Identification ◽

Energy Dispersive ◽

Objective Lens ◽

Ferritic Steels ◽

Replica Technique ◽

X Ray ◽

Large Numbers ◽

Scanning Transmission ◽

Made In

The advances in recent years in the microanalytical capabilities of conventional TEM's fitted with probe forming lenses allow much more detailed investigations to be made of the microstructures of complex alloys, such as ferritic steels, than have been possible previously. In particular, the identification of individual precipitate particles with dimensions of a few tens of nanometers in alloys containing high densities of several chemically and crystallographically different precipitate types is feasible. The aim of the investigation described in this paper was to establish a method which allowed individual particle identification to be made in a few seconds so that large numbers of particles could be examined in a few hours.A Philips EM400 microscope, fitted with the scanning transmission (STEM) objective lens pole-pieces and an EDAX energy dispersive X-ray analyser, was used at 120 kV with a thermal W hairpin filament. The precipitates examined were extracted using a standard C replica technique from specimens of a 2¼Cr-lMo ferritic steel in a quenched and tempered condition.

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Energy Dispersive X-Ray Measurements of thin Metal Foils

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092098 ◽

1976 ◽

Vol 34 ◽

pp. 426-427

Author(s):

J. Bentley ◽

E. A. Kenik

Keyword(s):

Materials Science ◽

Energy Dispersive Spectrometer ◽

Thin Foil ◽

Thin Metal ◽

Energy Dispersive ◽

Thin Specimen ◽

X Ray ◽

Metal Foils ◽

Small Probe ◽

Scanning Transmission

Instruments combining a 100 kV transmission electron microscope (TEM) with scanning transmission (STEM), secondary electron (SEM) and x-ray energy dispersive spectrometer (EDS) attachments to give analytical capabilities are becoming increasingly available and useful. Some typical applications in the field of materials science which make use of the small probe size and thin specimen geometry are the chemical analysis of small precipitates contained within a thin foil and the measurement of chemical concentration profiles near microstructural features such as grain boundaries, point defect clusters, dislocations, or precipitates. Quantitative x-ray analysis of bulk samples using EDS on a conventional SEM is reasonably well established, but much less work has been performed on thin metal foils using the higher accelerating voltages available in TEM based instruments.

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Preparation And elemental analysis of ancient fibers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126846 ◽

1987 ◽

Vol 45 ◽

pp. 410-411

Author(s):

Allen Angel ◽

Kathryn A. Jakes

Keyword(s):

Cross Sections ◽

Physical Structure ◽

Energy Dispersive ◽

Archaeological Sites ◽

X Ray ◽

Long Term Storage ◽

Backscattered Electron ◽

Electron Imaging

Fabrics recovered from archaeological sites often are so badly degraded that fiber identification based on physical morphology is difficult. Although diagenetic changes may be viewed as destructive to factors necessary for the discernment of fiber information, changes occurring during any stage of a fiber's lifetime leave a record within the fiber's chemical and physical structure. These alterations may offer valuable clues to understanding the conditions of the fiber's growth, fiber preparation and fabric processing technology and conditions of burial or long term storage (1).Energy dispersive spectrometry has been reported to be suitable for determination of mordant treatment on historic fibers (2,3) and has been used to characterize metal wrapping of combination yarns (4,5). In this study, a technique is developed which provides fractured cross sections of fibers for x-ray analysis and elemental mapping. In addition, backscattered electron imaging (BSI) and energy dispersive x-ray microanalysis (EDS) are utilized to correlate elements to their distribution in fibers.

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Computer programs for the calculation of x-ray intensities emitted by elements in multi-layer structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134685 ◽

1990 ◽

Vol 48 (2) ◽

pp. 216-217

Author(s):

G.F. Bastin ◽

H.J.M. Heijligers ◽

J.M. Dijkstra

Keyword(s):

Software Package ◽

Light Element ◽

Matrix Correction ◽

Excellent Performance ◽

Element Analysis ◽

X Ray ◽

Know How ◽

Accurate Knowledge ◽

Layer Structures ◽

Bulk Matrix

For the calculation of X-ray intensities emitted by elements present in multi-layer systems it is vital to have an accurate knowledge of the x-ray ionization vs. mass-depth (ϕ(ρz)) curves as a function of accelerating voltage and atomic number of films and substrate. Once this knowledge is available the way is open to the analysis of thin films in which both the thicknesses as well as the compositions can usually be determined simultaneously.Our bulk matrix correction “PROZA” with its proven excellent performance for a wide variety of applications (e.g., ultra-light element analysis, extremes in accelerating voltage) has been used as the basis for the development of the software package discussed here. The PROZA program is based on our own modifications of the surface-centred Gaussian ϕ(ρz) model, originally introduced by Packwood and Brown. For its extension towards thin film applications it is required to know how the 4 Gaussian parameters α, β, γ and ϕ(o) for each element in each of the films are affected by the film thickness and the presence of other layers and the substrate.

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