X Ray Microanalysis

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Dale E. Newbury - One of the best experts on this subject based on the ideXlab platform.

  • electron eXcited X Ray Microanalysis by energy dispersive spectrometry at 50 analytical accuracy precision trace sensitivity and quantitative compositional mapping
    Microscopy and Microanalysis, 2019
    Co-Authors: Dale E. Newbury, Nicholas W M Ritchie
    Abstract:

    2018 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.

  • X Ray Microanalysis case studies
    2018
    Co-Authors: Joseph I Goldstein, Dale E. Newbury, Nicholas W M Ritchie, Joseph R Michael, John Henry J Scott, David C Joy
    Abstract:

    Background: As part of a study into the in-service failure of the bearing surface of a large water pump, characterization was requested of the hard-facing alloy, which was observed to have separated from the stainless steel substrate, causing the failure.

  • measurement of trace constituents by electron eXcited X Ray Microanalysis with energy dispersive spectrometry
    Microscopy and Microanalysis, 2016
    Co-Authors: Dale E. Newbury, Nicholas W M Ritchie
    Abstract:

    Electron-eXcited X-Ray Microanalysis performed with scanning electron microscopy and energy-dispersive spectrometry (EDS) has been used to measure trace elemental constituents of compleX multielement materials, where “trace” refers to constituents present at concentrations below 0.01 (mass fraction). High count spectra measured with silicon drift detector EDS were quantified using the standards/matriX correction protocol embedded in the NIST DTSA-II software engine. Robust quantitative analytical results for trace constituents were obtained from concentrations as low as 0.000500 (mass fraction), even in the presence of significant peak interferences from minor (concentration 0.01≤ C ≤0.1) and major ( C >0.1) constituents. Limits of detection as low as 0.000200 were achieved in the absence of peak interference.

  • uncertainty estimates for electron probe X Ray Microanalysis measurements
    Analytical Chemistry, 2012
    Co-Authors: Nicholas W M Ritchie, Dale E. Newbury
    Abstract:

    It has been over 60 years since Castaing (Castaing, R. Application of Electron Probes to Local Chemical and Crystallographic Analysis. Ph.D. Thesis, University of Paris, Paris, France, 1951; translated by P. Duwez and D. Wittry, California Institute of Technology, 1955) introduced the technique of electron probe X-Ray Microanalysis (EPMA), yet the community remains unable to quantify some of the largest terms in the technique’s uncertainty budget. Historically, the EPMA community has assigned uncertainties to its measurements which reflect the measurement precision portion of the uncertainty budget and omitted terms related to the measurement accuracy. Yet, in many cases, the precision represents only a small fraction of the total budget. This paper addresses this shortcoming by considering two significant sources of uncertainty in the quantitative matriX correction models—the mass absorption coefficient, [μ/ρ], and the backscatter coefficient, η. Understanding the influence of these sources provides insi...

  • mistakes encountered during automatic peak identification of minor and trace constituents in electron eXcited energy dispersive X Ray Microanalysis
    Scanning, 2009
    Co-Authors: Dale E. Newbury
    Abstract:

    Automated peak identification in electron beam-eXcited X-Ray Microanalysis with energy dispersive X-Ray spectrometry has been shown to be subject to occasional mistakes even on well-separated, high-intensity peaks arising from major constituents (arbitrarily defined as a concentration, C, which eXceeds a mass fraction of 0.1). The peak identification problem becomes even more problematic for constituents present at minor (0.01≤C≤0.1) and trace (C<0.01) levels. “Problem elements” subject to misidentification as major constituents are even more vulnerable to misidentification when present at low concentrations in the minor and trace ranges. Additional misidentifications attributed to trace elements include minor X-Ray family members associated with major constituents but not assigned properly, escape and coincidence peaks associated with major constituents, and false peaks owing to chance groupings of counts in spectra with poor counting statistics. A strategy for robust identification of minor and trace elements can be based on application of automatic peak identification with careful inspection of the results followed by multiple linear least-squares peak fitting with complete peak references to systematically remove each identified major element from the spectrum before attempting to assign remaining peaks to minor and trace constituents. SCANNING 31: 91–101, 2009. Published by Wiley Periodicals, Inc.

Rene Van Grieken - One of the best experts on this subject based on the ideXlab platform.

  • an eXpert system for chemical speciation of individual particles using low z particle electron probe X Ray Microanalysis data
    Analytical Chemistry, 2004
    Co-Authors: Hyekyeong Kim, Rene Van Grieken
    Abstract:

    An electron probe X-Ray Microanalysis (EPMA) technique, using an energy-dispersive X-Ray detector with an ultrathin window, designated a low-Z particle EPMA, has been developed. The low-Z particle EPMA allows the quantitative determination of concentrations of low-Z elements, such as C, N, and O, as well as chemical elements that can be analyzed by conventional energy-dispersive EPMA, in individual particles. Since a data set is usually composed of data for several thousands of particles in order to make environmentally meaningful observations of real atmospheric aerosol samples, the development of a method that fully eXtracts chemical information contained in the low-Z particle EPMA data is important. An eXpert system that can rapidly and reliably perform chemical speciation from the low-Z particle EPMA data is presented. This eXpert system tries to mimic the logics used by eXperts and is implemented by applying macroprogramming available in MS EXcel software. Its feasibility is confirmed by applying the...

  • single particle analysis of aerosols at cheju island korea using low z electron probe X Ray Microanalysis a direct proof of nitrate formation from sea salts
    Environmental Science & Technology, 2001
    Co-Authors: Hyekyeong Kim, Yong Pyo Kim, Chong Bum Lee, Kihyun Kim, Chang Hee Kang, Janos Osan, Johan De Hoog, And Anna Worobiec, Rene Van Grieken
    Abstract:

    A recently developed electron probe X-Ray Microanalysis (EPMA), called low-Z EPMA, employing an ultrathin window energy-dispersive X-Ray detector, was applied to characterize aerosol particles collected at two sampling sites, namely, Kosan and 1100 Hill of Cheju Island, Korea, on a summer day in 1999. Since low-Z EPMA can provide quantitative information on the chemical composition of aerosol particles, the collected aerosol particles were classified and analyzed based on their chemical species. Many different particle types were identified, such as marine-originated, carbonaceous, soil-derived, and anthropogenic particles. Marine-originated particles, such as NaNO3- and Na2SO4-containing particles, are very frequently encountered in the two samples. In this study, it was directly proven that the observed nitrate particles were from sea salts. In addition, two types of nitrate particles from sea salts were observed, with and without Mg. The sodium nitrate particles without Mg were believed to be collected...

  • chemical speciation of individual atmospheric particles using low z electron probe X Ray Microanalysis characterizing asian dust deposited with rainwater in seoul korea
    Atmospheric Environment, 2001
    Co-Authors: Hyekyeong Kim, Janos Osan, Johan De Hoog, Youngsin Chun, Rene Van Grieken
    Abstract:

    Abstract Chemical speciation of individual microparticles is of much interest in environmental atmospheric chemistry; e.g. the determination of the elemental concentrations in individual atmospheric aerosol particles is important to study the chemical behavior of atmospheric pollution. Recently, an EPMA technique using an X-Ray detector equipped with an ultra-thin window, allowing EPMA to determine concentrations of low-Z elements, such as C, N, and O, in individual particles of micrometer size, has been developed. This technique, called low-Z electron probe X-Ray Microanalysis (low-Z EPMA), is applied to characterize the water-insoluble part of “Asian Dust”, deposited by washout in the form of rainwater during an Asian Dust storm event and collected in Seoul, Korea. In this study, it was demonstrated that the single particle analysis using low-Z EPMA provided detailed information on various types of chemical species in the sample. In addition to aluminosilicates, silicon oXide, iron oXide, and calcium carbonate particles, which are eXpected to be present, carbonaceous particles are also observed in a significant fraction. This uneXpected finding that particle sample originated from an arid area contains significant amount of carbonaceous particles is supported by the investigation of a “China Loess” sample. In addition, we also performed single particle analysis for a local soil sample, in order to check the possible influence from local sources on “Asian Dust”. The characteristics of the local soil particle sample, e.g. the types of aluminosilicate particles and the abdundance of particles with deviating chemical species, are clearly different from “Asian Dust” and “China Loess” samples, whereas those two are similar, implying that the “Asian Dust” sample was not much influenced by local sources.

Raynald Gauvin - One of the best experts on this subject based on the ideXlab platform.

  • inverse modeling for quantitative X Ray Microanalysis applied to 2d heterogeneous materials
    Ultramicroscopy, 2020
    Co-Authors: Yu Yuan, Hendrix Demers, Nicolas Brodusch, Xianglong Wang, Raynald Gauvin
    Abstract:

    Abstract Current quantitative X-Ray Microanalysis methods are only available for homogeneous materials. This paper presents a newly developed inverse modeling algorithm to determine both the structure and composition of two-dimensional (2D) heterogeneous materials from a series of X-Ray intensity measurements under different beam energies and beam positions. It utilizes an iterative process of forward modeling to determine the optimal specimen to minimize the relative differences between the simulated and eXperimental characteristic X-Ray intensities. The Monte Carlo method is used for the forward modeling to predict the X-Ray radiation for a given specimen and eXperimental setup. Several eXamples of applications are presented for different types of samples with one-dimensional (1D) and 2D structures, in which the simulated X-Ray intensities from phantom samples are used as input. Most of the results obtained from our algorithm agree well with the phantom samples. Some discrepancies are found for the voXels located at deeper depths of the 2D samples. And the discrepancies may be attributed to errors from the Monte Carlo simulations and from the variation of the X-Ray range with beam energy. As a proof-of-concept work, this paper confirms the feasibility of our inverse modeling algorithm applied to 2D heterogeneous materials.

  • the f ratio quantification method for X Ray Microanalysis applied to mg al zn alloys
    Microscopy and Microanalysis, 2019
    Co-Authors: Chaoyi Teng, Hendrix Demers, Xin Chu, Raynald Gauvin
    Abstract:

    The f-ratio quantitative X-Ray Microanalysis method has been recently developed for binary systems based on a scanning electron microscope/energy dispersive spectroscopy (SEM/EDS) system. This method incorporates traditional EDS eXperiments and Monte Carlo simulations, and calibration factors are calculated with standard samples to evaluate the differences between them. In this work, the f-ratio method was eXtended to Mg-Al-Zn multi-element systems using a cold field emission SEM and a tungsten emission SEM. Results show that the stability of the beam current does not influence the f-ratio quantification accuracy. Thus, the f-ratio method is suitable for quantitative X-Ray mapping with a long-time acquisition or even an unstable beam current. Comparing with other quantitative techniques including the routine standardless analysis and the standard-based k-ratio method, the f-ratio method is a simple and accurate quantification method.

  • The f-Ratio Method for X-Ray Microanalysis in the SEM
    Field Emission Scanning Electron Microscopy, 2017
    Co-Authors: Nicolas Brodusch, Hendrix Demers, Raynald Gauvin
    Abstract:

    Quantitative X-Ray Microanalysis of bulk samples is usually obtained by measuring the characteristic X-Ray intensities of each element in a sample and in a corresponding standard of known composition.

  • what remains to be done to allow quantitative X Ray Microanalysis performed with eds to become a true characterization technique
    Microscopy and Microanalysis, 2012
    Co-Authors: Raynald Gauvin
    Abstract:

    This article reviews different methods used to perform quantitative X-Ray Microanalysis in the electron microscope and also demonstrates the urgency of measuring the fundamental parameters of X-Ray generation for the development of accurate standardless quantitative methods. Using ratios of characteristic lines acquired on the same X-Ray spectrum, it is shown that the Cliff and Lorimer K A - B factor can be used in a general correction method that is appropriate for all types of specimens and electron microscopes, providing that appropriate corrections are made for X-Ray absorption, fluorescence, and indirect generation. Since the fundamental parameters appear in the K A - B factor, only the ratio of the ionization cross sections needs to be known, not their absolute values. In this regard, the measurement of ratios of the K A - B factor (or intensities at different beam energies of the same material with no change of beam spreading in the material) permits the validation for the best models to compute the ratio of ionization cross sections. It is shown, using this method, that the nonrelativistic Bethe equation, to compute ionization cross section, is very close to the equation of E. Casnati et al. ( J Phys B 15 , 155–167, 1982) and also to the equations proposed by D. Bote and F. Salvat ( Phys Rev A 77 , 042701, 2008) for the computation of the ratio of ionization cross sections. The method is eXtended to show that it could be used to determine the values of the Coster-Kronig transitions factors, an important fundamental parameter for the generation of L and M lines that is mostly known with poor accuracy. The detector efficiency can be measured with specimens where their intensities were measured with an energy dispersive spectrometer detector, the efficiency of which has been measured in an X-Ray synchrotron (M. Alvisi et al., Microsc Microanal 12 , 406–415, 2006). The spatial resolution should always be computed when performing quantitative X-Ray Microanalysis and the equations of R. Gauvin ( Microsc Microanal 13 (5), 354–357, 2007) for bulk materials and the one presented in this article for thin films should be used. The effects of X-Rays generated by fast secondary electrons and by Auger electrons are reviewed, and their effect can be detrimental for the spatial resolution of materials involving low-energy X-Ray lines, in certain specific conditions. Finally, quantitative X-Ray Microanalysis of heterogeneous materials is briefly reviewed.

  • development of a new quantitative X Ray Microanalysis method for electron microscopy
    Microscopy and Microanalysis, 2010
    Co-Authors: Paula Horny, Eric Lifshin, Helen Campbell, Raynald Gauvin
    Abstract:

    Quantitative X-Ray Microanalysis of thick samples is usually performed by measuring the characteristic X-Ray intensities of each element in a sample and in corresponding standards. The ratio of the measured intensities from the unknown material to that from the standard is related to the concentration using the ZAF or ϕ(ρz) equations. Under optimal conditions, accuracies approaching 1% are possible. However, all the eXperimental conditions must remain the same during the sample and standard measurements. This is not possible with cold field emission scanning electron microscopes (FE-SEMs) where beam current can fluctuate around 5% in its stable regime. Very little work has been done on variable beam current conditions (Griffin, B.J. & Nockolds, C.E., Scanning 13, 307-312, 1991), and none relating to cold FE-SEM applications. To address this issue, a new method was developed using a single spectral measurement. It is similar in approach to the Cliff-Lorimer method developed for the analytical transmission electron microscope. However, corrections are made for X Rays generated from thick specimens using the ratio of the characteristic X-Ray intensities of two elements in the same material. The proposed method utilizes the ratio of the intensity of a characteristic X-Ray normalized by the sum of X-Ray intensities of all the elements measured for the sample, which should also reduce the amplitude of error propagation. Uncertainties in the physical parameters of X-Ray generation are corrected using a calibration factor that must be previously acquired or calculated. As an eXample, when this method was applied to the calculation of the composition of Au-Cu National Institute of Standards and Technology standards measured with a cold field emission source SEM, relative accuracies better than 5% were obtained.

Hyekyeong Kim - One of the best experts on this subject based on the ideXlab platform.

  • characterization of individual atmospheric aerosols using quantitative energy dispersive electron probe X Ray Microanalysis a review
    Asian journal of atmospheric environment, 2010
    Co-Authors: Hyekyeong Kim
    Abstract:

    Great concerns about atmospheric aerosols are attributed to their multiple roles to atmospheric processes. For eXample, atmospheric aerosols influence global climate, directly by scattering or absorbing solar radiations and indirectly by serving as cloud condensation nuclei. They also have a significant impact on human health and visibility. Many of these effects depend on the size and composition of atmospheric aerosols, and thus detailed information on the physicochemical properties and the distribution of airborne particles is critical to accurately predict their impact on the Earth’s climate as well as human health. A single particle analysis technique, named low-Z particle electron probe X-Ray Microanalysis (low-Z particle EPMA) that can determine the concentration of low-Z elements such as carbon, nitrogen and oXygen in a microscopic volume has been developed. The capability of quantitative analysis of low-Z elements in individual particle allows the characterization of especially important atmospheric particles such as sulfates, nitrates, ammonium, and carbonaceous particles. Furthermore, the diversity and the complicated heterogeneity of atmospheric particles in chemical compositions can be investigated in detail. In this review, the development and methodology of low-Z particle EPMA for the analysis of atmospheric aerosols are introduced. Also, its typical applications for the characterization of various atmospheric particles, i.e., on the chemical compositions, morphologies, the size segregated distributions, and the origins of Asian dust, urban aerosols, indoor aerosols in underground subway station, and Arctic aerosols, are illustrated.

  • an eXpert system for chemical speciation of individual particles using low z particle electron probe X Ray Microanalysis data
    Analytical Chemistry, 2004
    Co-Authors: Hyekyeong Kim, Rene Van Grieken
    Abstract:

    An electron probe X-Ray Microanalysis (EPMA) technique, using an energy-dispersive X-Ray detector with an ultrathin window, designated a low-Z particle EPMA, has been developed. The low-Z particle EPMA allows the quantitative determination of concentrations of low-Z elements, such as C, N, and O, as well as chemical elements that can be analyzed by conventional energy-dispersive EPMA, in individual particles. Since a data set is usually composed of data for several thousands of particles in order to make environmentally meaningful observations of real atmospheric aerosol samples, the development of a method that fully eXtracts chemical information contained in the low-Z particle EPMA data is important. An eXpert system that can rapidly and reliably perform chemical speciation from the low-Z particle EPMA data is presented. This eXpert system tries to mimic the logics used by eXperts and is implemented by applying macroprogramming available in MS EXcel software. Its feasibility is confirmed by applying the...

  • single particle analysis of aerosols at cheju island korea using low z electron probe X Ray Microanalysis a direct proof of nitrate formation from sea salts
    Environmental Science & Technology, 2001
    Co-Authors: Hyekyeong Kim, Yong Pyo Kim, Chong Bum Lee, Kihyun Kim, Chang Hee Kang, Janos Osan, Johan De Hoog, And Anna Worobiec, Rene Van Grieken
    Abstract:

    A recently developed electron probe X-Ray Microanalysis (EPMA), called low-Z EPMA, employing an ultrathin window energy-dispersive X-Ray detector, was applied to characterize aerosol particles collected at two sampling sites, namely, Kosan and 1100 Hill of Cheju Island, Korea, on a summer day in 1999. Since low-Z EPMA can provide quantitative information on the chemical composition of aerosol particles, the collected aerosol particles were classified and analyzed based on their chemical species. Many different particle types were identified, such as marine-originated, carbonaceous, soil-derived, and anthropogenic particles. Marine-originated particles, such as NaNO3- and Na2SO4-containing particles, are very frequently encountered in the two samples. In this study, it was directly proven that the observed nitrate particles were from sea salts. In addition, two types of nitrate particles from sea salts were observed, with and without Mg. The sodium nitrate particles without Mg were believed to be collected...

  • chemical speciation of individual atmospheric particles using low z electron probe X Ray Microanalysis characterizing asian dust deposited with rainwater in seoul korea
    Atmospheric Environment, 2001
    Co-Authors: Hyekyeong Kim, Janos Osan, Johan De Hoog, Youngsin Chun, Rene Van Grieken
    Abstract:

    Abstract Chemical speciation of individual microparticles is of much interest in environmental atmospheric chemistry; e.g. the determination of the elemental concentrations in individual atmospheric aerosol particles is important to study the chemical behavior of atmospheric pollution. Recently, an EPMA technique using an X-Ray detector equipped with an ultra-thin window, allowing EPMA to determine concentrations of low-Z elements, such as C, N, and O, in individual particles of micrometer size, has been developed. This technique, called low-Z electron probe X-Ray Microanalysis (low-Z EPMA), is applied to characterize the water-insoluble part of “Asian Dust”, deposited by washout in the form of rainwater during an Asian Dust storm event and collected in Seoul, Korea. In this study, it was demonstrated that the single particle analysis using low-Z EPMA provided detailed information on various types of chemical species in the sample. In addition to aluminosilicates, silicon oXide, iron oXide, and calcium carbonate particles, which are eXpected to be present, carbonaceous particles are also observed in a significant fraction. This uneXpected finding that particle sample originated from an arid area contains significant amount of carbonaceous particles is supported by the investigation of a “China Loess” sample. In addition, we also performed single particle analysis for a local soil sample, in order to check the possible influence from local sources on “Asian Dust”. The characteristics of the local soil particle sample, e.g. the types of aluminosilicate particles and the abdundance of particles with deviating chemical species, are clearly different from “Asian Dust” and “China Loess” samples, whereas those two are similar, implying that the “Asian Dust” sample was not much influenced by local sources.

Nicholas W M Ritchie - One of the best experts on this subject based on the ideXlab platform.

  • Scanning Electron Microscopy and X-Ray Microanalysis
    Springer, 2020
    Co-Authors: Joseph R Michael, Nicholas W M Ritchie, John Henry J Scott, David C.
    Abstract:

    This thoroughly revised and updated Fourth Edition of a time-honored teXt provides the reader with a comprehensive introduction to the field of scanning electron microscopy (SEM), energy dispersive X-Ray spectrometry (EDS) for elemental Microanalysis, electron backscatter diffraction analysis (EBSD) for micro-crystallography and focused ion beams. Students and academic researchers will find the teXt to be an authoritative and scholarly resource, while SEM operators and a diversity of practitioners — engineers, technicians, physical and biological scientists, clinicians, and technical managers — will find that every chapter has been overhauled to meet the more practical needs of the technologist and working professional. In a break with the past, this Fourth Edition de-emphasizes the design and physical operating basis of the instrumentation, including the electron sources, lenses, detectors, etc. In the modern SEM, many of the low level instrument parameters are now controlled and optimized by the microscope’s software, and user access is restricted. Although the software control system provides efficient and reproducible microscopy and Microanalysis, the user must understand the parameter space wherein choices are made to achieve effective andmeaningful microscopy, Microanalysis, and micro-crystallography. Therefore, special emphasis is placed on beam energy, beam current, electron detector characteristics and controls, and ancillary techniques such as energy dispersive X-Ray spectrometry (EDS) and electron backscatter diffraction (EBSD)

  • electron eXcited X Ray Microanalysis by energy dispersive spectrometry at 50 analytical accuracy precision trace sensitivity and quantitative compositional mapping
    Microscopy and Microanalysis, 2019
    Co-Authors: Dale E. Newbury, Nicholas W M Ritchie
    Abstract:

    2018 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.

  • X Ray Microanalysis case studies
    2018
    Co-Authors: Joseph I Goldstein, Dale E. Newbury, Nicholas W M Ritchie, Joseph R Michael, John Henry J Scott, David C Joy
    Abstract:

    Background: As part of a study into the in-service failure of the bearing surface of a large water pump, characterization was requested of the hard-facing alloy, which was observed to have separated from the stainless steel substrate, causing the failure.

  • measurement of trace constituents by electron eXcited X Ray Microanalysis with energy dispersive spectrometry
    Microscopy and Microanalysis, 2016
    Co-Authors: Dale E. Newbury, Nicholas W M Ritchie
    Abstract:

    Electron-eXcited X-Ray Microanalysis performed with scanning electron microscopy and energy-dispersive spectrometry (EDS) has been used to measure trace elemental constituents of compleX multielement materials, where “trace” refers to constituents present at concentrations below 0.01 (mass fraction). High count spectra measured with silicon drift detector EDS were quantified using the standards/matriX correction protocol embedded in the NIST DTSA-II software engine. Robust quantitative analytical results for trace constituents were obtained from concentrations as low as 0.000500 (mass fraction), even in the presence of significant peak interferences from minor (concentration 0.01≤ C ≤0.1) and major ( C >0.1) constituents. Limits of detection as low as 0.000200 were achieved in the absence of peak interference.

  • uncertainty estimates for electron probe X Ray Microanalysis measurements
    Analytical Chemistry, 2012
    Co-Authors: Nicholas W M Ritchie, Dale E. Newbury
    Abstract:

    It has been over 60 years since Castaing (Castaing, R. Application of Electron Probes to Local Chemical and Crystallographic Analysis. Ph.D. Thesis, University of Paris, Paris, France, 1951; translated by P. Duwez and D. Wittry, California Institute of Technology, 1955) introduced the technique of electron probe X-Ray Microanalysis (EPMA), yet the community remains unable to quantify some of the largest terms in the technique’s uncertainty budget. Historically, the EPMA community has assigned uncertainties to its measurements which reflect the measurement precision portion of the uncertainty budget and omitted terms related to the measurement accuracy. Yet, in many cases, the precision represents only a small fraction of the total budget. This paper addresses this shortcoming by considering two significant sources of uncertainty in the quantitative matriX correction models—the mass absorption coefficient, [μ/ρ], and the backscatter coefficient, η. Understanding the influence of these sources provides insi...