A peak‐to‐background method for electron‐probe x‐ray microanalysis applied to individual small particles

Lábár, János L.; Török, Szabina

doi:10.1002/xrs.1300210407

Cited by 17 publications

(14 citation statements)

References 20 publications

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“…As it is the least likely element to be dissolved and transported elsewhere under the conditions of the experiment, it can, thus, be used as a proxy for tracking the local variations of all the other probed elements relative to the original bentonite. The so-called BAl-normalized^values were computed directly from the quantification results (Lábár and Török 1992;Trincavelli et al 2014). For a given element, each point of the profile represents the average ratio of the content in this element over the Al content of a given column of the analysis grid.…”

Section: Sem-edx Analysesmentioning

confidence: 99%

Eighteen years of steel–bentonite interaction in the FEBEX in situ test at the Grimsel Test Site in Switzerland

Hadi

Wersin

Serneels

et al. 2019

Clays and clay miner.

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Corrosion of steel canisters containing buried high-level radioactive waste is a relevant issue for the long-term integrity of repositories. The purpose of the present study was to evaluate this issue by examining two differently corroded blocks originating from a full-scale in situ test of the FEBEX bentonite site in Switzerland. The FEBEX experiment was designed initially as a feasibility test of an engineered clay barrier system and was recently dismantled after 18 years of activity. Samples were studied by Fspatially resolved`and Fbulk`experimental methods, including Scanning Electron Microscopy, Elemental Energy Dispersive Spectroscopy (SEM-EDX), μ-Raman spectroscopy, X-ray Fluorescence (XRF), X-ray Diffraction (XRD), and 57 Fe Mössbauer spectrometry, with a focus on Fe-bearing phases. In one of the blocks, corrosion of the steel liner led to diffusion of Fe into the bentonite, resulting in the formation of large (width > 140 mm) red, orange, and blue colored halos. Goethite was identified as the main corrosion product in the red and orange zones while no excess Fe 2+ (compared to the unaffected bentonite) was observed there. Excess Fe 2+ was found to have diffused further into the clay (in the blue zones) but its speciation could not be unambiguously clarified. The results indicate the occurrence of newly formed octahedral Fe 2+ either as Fe 2+ sorbed on the clay or as structural Fe 2+ inside the clay (following electron transfer from sorbed Fe 2+). No other indications of clay transformation or newly formed clay phases were found. The overall pattern indicates that diffusion of Fe was initiated when oxidizing conditions were still prevailing inside the bentonite block, resulting in the accumulation of Fe 3+ close to the interface (up to three times the original Fe content), and continued when reducing conditions were reached, allowing deeper diffusion of Fe 2+ into the clay (inducing an increase of 10-12% of the Fe content).

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Section: Sem-edx Analysesmentioning

confidence: 99%

Eighteen years of steel–bentonite interaction in the FEBEX in situ test at the Grimsel Test Site in Switzerland

Hadi

Wersin

Serneels

et al. 2019

Clays and clay miner.

View full text Add to dashboard Cite

show abstract

“…As the beam energy increases, the maximum continuum energy increases. Note that at certain beam energy (less than 5 keV), a small particle has higher background intensity in comparison with a big particle ( Figure 2(b) ) because of the electron transition phenomenon [ 4 ]. The peak and background intensities for all particles are the same as long as the beam energy is less than 5 keV.…”

Section: Resultsmentioning

confidence: 99%

“…Finally, for small particles, the randomization process of electrons has not been completed before they leave the particles. Therefore, the anisotropy in the bremsstrahlung X-ray may not be negligible [ 2 – 4 ]. Several methods including the Armstrong model [ 5 ], the peak to background (P/B) method [ 6 , 7 ], and the Monte Carlo simulations [ 1 ] have been proposed to overcome this matter.…”

Section: Introductionmentioning

confidence: 99%

“…Rez and Konopka [ 3 ] indicated that the P/B increases with increasing overvoltage; therefore, the voltage dependence to the P/B ratio means that it is not truly independent of geometry. Researchers [ 4 , 12 ] showed that the most likely source of error in the P/B method is the uncertainty in the calculation of the Bremsstrahlung spectrum intensity. However, Heckel and Jugelt [ 13 ] pointed that the influence of statistical errors of the Bremsstrahlung spectrum counts can be diminished by prolonging the measuring times.…”

Section: Introductionmentioning

confidence: 99%

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Study of the Peak to Background (P/B) Method Behavior as a Function of Take-Off Angle, Tilt Angle, Particle Size, and Beam Energy

2021

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Monte Carlo simulations were performed to investigate the behavior of the peak to background ratio (P/B) of particles on a substrate as a function of different variables such as take-off angle, tilt angle, particle size, and beam energy. The results showed that the P/B highly depends on the beam energy, the size of particles, and the composition of the substrates. Results showed that the rate of intensity reduction of the peak is less than the background for a high tilt angle (60 degrees), and thereby, the P/B increases at a high tilt angle. It was shown that by increasing the take-off angle, the P/B initially reduces and then reaches a plateau. Results showed that the P/B highly depends on the size of particles. Analyses showed that by moving the electron beam from the center to the side of the particle, the P/B increases. Finally, the spherical particles have higher sensitivity of the P/B to the beam position than the cubical particles.

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“…Another quantification method is the standardless peak-to-background (P/B) method without using bulk standards (Lábár and Török, 1992). The method assumes that both characteristic and Bremsstrahlung background X-ray photons are emitted from the same region of the sample and experience the same absorption effect on their way to the detector.…”

Section: Low-z Particle Epmamentioning

confidence: 99%

Characterization of Individual Atmospheric Aerosols Using Quantitative Energy Dispersive-Electron Probe X-ray Microanalysis: A Review

Kim¹,

Ro²

2010

ajae

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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.

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A peak‐to‐background method for electron‐probe x‐ray microanalysis applied to individual small particles

Cited by 17 publications

References 20 publications

Eighteen years of steel–bentonite interaction in the FEBEX in situ test at the Grimsel Test Site in Switzerland

Eighteen years of steel–bentonite interaction in the FEBEX in situ test at the Grimsel Test Site in Switzerland

Study of the Peak to Background (P/B) Method Behavior as a Function of Take-Off Angle, Tilt Angle, Particle Size, and Beam Energy

Characterization of Individual Atmospheric Aerosols Using Quantitative Energy Dispersive-Electron Probe X-ray Microanalysis: A Review

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