Electron-Excited X-ray Microanalysis by Energy Dispersive Spectrometry at 50: Analytical Accuracy, Precision, Trace Sensitivity, and Quantitative Compositional Mapping

Abstract2018 marked the 50th anniversary of the introduction of energy dispersive X-ray spectrometry (EDS) with semiconductor detectors to electron-excited X-ray microanalysis. Initially useful for qualitative analysis, EDS has developed into a fully quantitative analytical tool that can match wavelength dispersive spectrometry for accuracy in the determination of major (mass concentration C > 0.1) and minor (0.01 ≤ C ≤ 0.1) constituents, and useful accuracy can extend well into the trace (0.001 < C < 0.01) constituent range even when severe peak interference occurs. Accurate analysis is possible for low atomic number elements (B, C, N, O, and F), and at low beam energy, which can optimize lateral and depth spatial resolution. By recording a full EDS spectrum at each picture element of a scan, comprehensive quantitative compositional mapping can also be performed.

Download Full-text

Impact of Energy-Dispersive Spectrometry in Materials Science Microanalysis

Microscopy and Microanalysis ◽

10.1017/s1431927698980540 ◽

1998 ◽

Vol 4 (6) ◽

pp. 567-575 ◽

Cited By ~ 1

Author(s):

David B. Williams

Keyword(s):

Grain Boundaries ◽

Energy Dispersive Spectrometry ◽

Equilibrium Phase ◽

Boundary Segregation ◽

Temper Embrittlement ◽

Energy Dispersive ◽

Small Scale ◽

X Ray ◽

Elemental Segregation

X-ray microanalysis of materials using energy-dispersive spectrometry (EDS) has made the greatest impact in studies of compositional changes at atomic-level interfaces. The small physical dimensions of the silicon detector make EDS the X-ray analyzer of choice for analytical transmission electron microscopy (AEM). X-ray analysis of thin foils in the AEM has contributed to our understanding of elemental segregation to interphase interfaces and grain boundaries, as well as other planar defects. Measurement of atomic diffusion on a small scale close to interphase interfaces has permitted determination of substitutional atomic diffusivities several orders of magnitude smaller than previously possible and has also led to the determination of low-temperature equilibrium phase diagrams through the measurement of local interface compositions. Elemental segregation to grain boundaries is responsible for such deleterious behavior as temper embrittlement, stress-corrosion cracking, and other forms of intergranular failure. On the other hand, segregation can bring about improvement in behavior: sintering aids in ceramics and de-embrittlement of intermetallics. EDS in the AEM has been responsible for quantitative analysis of all aspects of the segregation process and, more recently, in combination with electron energy-loss spectrometry (EELS) has given insight into why boundary segregation results in such significant macroscopic changes in properties.

Download Full-text

Areas for Improvement in XRF Analysis of Low Atomic Number Elements

Advances in X-ray Analysis ◽

10.1154/s0376030800018668 ◽

1992 ◽

Vol 36 ◽

pp. 73-80

Author(s):

Bruno A.R. Vrebos ◽

Gjalt T.J. Kuipéres

Keyword(s):

Lower Limit ◽

Atomic Number ◽

Energy Dispersive Spectrometry ◽

Limit Of Detection ◽

Heavy Elements ◽

Fluorescence Spectrometry ◽

Accurate Analysis ◽

X Ray ◽

Made In

Accurate analysis of the light elements has been, from the early applications of X-ray fluorescence spectrometry a struggle compared to the determination of heavy elements in the same matrices. In contrast, there has been virtually no upper limit to the atomic number of the element that could be determined. The lower limit, however, has been continuously adjusted downward through the years. Clearly, the sensitivity as well as the lower limit of detection for the heavy elements have also been improved, but the effect is Jess striking than the advances made in the region of tight element performance. This paper deals specifically with wavelength dispersive sequential x-ray fluorescence spectrometry, although some of the observations made are equally applicable to energy dispersive spectrometry.

Download Full-text

Determination of low levels of transmutation-induced silicon in an aluminium reactor component using X-ray energy dispersive spectrometry

Radiation Effects and Defects in Solids ◽

10.1080/10420159708216850 ◽

1997 ◽

Vol 140 (3-4) ◽

pp. 243-262 ◽

Cited By ~ 3

Author(s):

D. R. G. Mitchell ◽

R. A. Day

Keyword(s):

Energy Dispersive Spectrometry ◽

Energy Dispersive ◽

X Ray ◽

Low Levels

Download Full-text

Microcalorimeter Energy Dispersive Spectrometry for Low Voltage SEM

Microscopy and Microanalysis ◽

10.1017/s1431927600014847 ◽

1999 ◽

Vol 5 (S2) ◽

pp. 304-305

Author(s):

D. A. Wollman ◽

Dale E. Newbury ◽

G. C. Hilton ◽

K. D. Irwin ◽

D. A. Rudman ◽

...

Keyword(s):

Beam Energy ◽

Energy Dispersive Spectrometry ◽

Low Voltage ◽

Beam Current ◽

Energy Dispersive ◽

X Rays ◽

Light Elements ◽

X Ray ◽

Wavelength Dispersive Spectrometry ◽

Scanning Electron

Microanalysis performed at low electron beam energies (≤ 5 keV) is limited by the physics of x-ray generation and the performance of existing semiconductor energy dispersive spectrometry (EDS) and wavelength dispersive spectrometry (WDS). Low beam energy restricts the atomic shells that can be excited for elements of intermediate and high atomic number, forcing the analyst to consider using unconventional M- and N-shells for elements such as Sn and Au. Unfortunately, these shells have very low fluorescent yield, which results in inherently low spectral peak-to-background ratios. The modest energy resolution of semiconductor EDS leads to poor limits of detection for these weakly emitted photons. The situation is further complicated by the inevitable interferences with the much more strongly excited K-shell x-rays of the light elements, particularly carbon and oxygen. WDS has the spectral resolution to overcome the resolution limitations of semiconductor EDS. However, WDS has a low geometric efficiency, and because of its narrow instantaneous spectral transmission, spectral scanning is required to detect and analyze x-ray peaks. Moreover, the high resolution field-emission-gun scanning electron microscope (FEG-SEM) provides only a few nanoamperes of beam current.

Download Full-text

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.

Download Full-text