scholarly journals Possible Pitfalls in the Analysis of Minerals and Loose Materials by Portable XRF, and How to Overcome Them

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 33
Author(s):  
Valérie Laperche ◽  
Bruno Lemière
Keyword(s):  
Fluorescence Spectroscopy ◽  
Laboratory Data ◽  
Data Sets ◽  
Light Elements ◽  
Portable Xrf ◽  
X Ray ◽  
Protective Films ◽  
The Matrix ◽  
Valuable Complement ◽  
Physical Effects

Portable X-ray fluorescence spectroscopy is now widely used in almost any field of geoscience. Handheld XRF analysers are easy to use, and results are available in almost real time anywhere. However, the results do not always match laboratory analyses, and this may deter users. Rather than analytical issues, the bias often results from sample preparation differences. Instrument setup and analysis conditions need to be fully understood to avoid reporting erroneous results. The technique’s limitations must be kept in mind. We describe a number of issues and potential pitfalls observed from our experience and described in the literature. This includes the analytical mode and parameters; protective films; sample geometry and density, especially for light elements; analytical interferences between elements; physical effects of the matrix and sample condition, and more. Nevertheless, portable X-ray fluorescence spectroscopy (pXRF) results gathered with sufficient care by experienced users are both precise and reliable, if not fully accurate, and they can constitute robust data sets. Rather than being a substitute for laboratory analyses, pXRF measurements are a valuable complement to those. pXRF improves the quality and relevance of laboratory data sets.

scholarly journals Synchrotron-based X-ray tomographic microscopy for rock physics investigations

Geophysics ◽  
2013 ◽  
Vol 78 (1) ◽  
pp. D53-D64 ◽  
Author(s):  
Claudio Madonna ◽  
Beatriz Quintal ◽  
Marcel Frehner ◽  
Bjarne S. G. Almqvist ◽  
Nicola Tisato ◽  
...  
Keyword(s):  
High Resolution ◽  
Pore Space ◽  
Laboratory Data ◽  
Image Data ◽  
Rock Physics ◽  
Nondestructive Method ◽  
Rock Properties ◽  
Data Sets ◽  
X Ray ◽  
Rock Types

Synchrotron radiation X-ray tomographic microscopy is a nondestructive method providing ultra-high-resolution 3D digital images of rock microstructures. We describe this method and, to demonstrate its wide applicability, we present 3D images of very different rock types: Berea sandstone, Fontainebleau sandstone, dolomite, calcitic dolomite, and three-phase magmatic glasses. For some samples, full and partial saturation scenarios are considered using oil, water, and air. The rock images precisely reveal the 3D rock microstructure, the pore space morphology, and the interfaces between fluids saturating the same pore. We provide the raw image data sets as online supplementary material, along with laboratory data describing the rock properties. By making these data sets available to other research groups, we aim to stimulate work based on digital rock images of high quality and high resolution. We also discuss and suggest possible applications and research directions that can be pursued on the basis of our data.

Light-Element EPMA—Correlations, convolutions, and true concentrations

1996 ◽  
Vol 54 ◽  
pp. 482-483
Author(s):  
Alfred Kracher ◽  
Joel F. Flumerfelt ◽  
Iver E. Anderson
Keyword(s):  
Light Element ◽  
Al Alloys ◽  
Reliable Data ◽  
Processing Conditions ◽  
Light Elements ◽  
Gaseous Species ◽  
X Ray ◽  
Number Of Factors ◽  
The Matrix

Analyses of small concentrations of light elements by electron microprobe are complicated by a number of factors, including low signal strength and line overlap. Obtaining reliable data may require techniques that are uncommon in wavelength-dispersive (WDS) x-ray analysis. A case in point is the investigation of alloys that contain small amounts of nitrogen. Nitridation of Al metal and Al alloys with N-bearing gaseous species is being studied as a way to form in situ nitride precipitates, which is of interest for altering the mechanical properties of these materials. It was found, for example, that one specific alloy with 1.7 wt% Ti and 7.7 wt% Y retains much larger N concentrations on nitridation than pure Al, using the same processing conditions for both alloys. Nitrogen may be present in TiAl3 precipitates, YA13 precipitates, or the matrix. Identifying the N-bearing compound by EPMA has proven difficult, however, because of the interference of Lℓ on N Ka, combined with the low peak/background ratio of the N Ka peak.

scholarly journals Comparative Study of Three Mixing Methods in Fusion Technique for Determining Major and Minor Elements Using Wavelength Dispersive X-ray Fluorescence Spectroscopy

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5325
Author(s):  
Dan-Ping Zhang ◽  
Ding-Shuai Xue ◽  
Yan-Hong Liu ◽  
Bo Wan ◽  
Qian Guo ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Fluorescence Spectroscopy ◽  
Matrix Effects ◽  
Certified Reference Materials ◽  
Accurate Analysis ◽  
X Ray ◽  
Minor Elements ◽  
The Matrix ◽  
Sample Preparation Procedure ◽  
Coefficient Method

Accurate analysis using a simple and rapid procedure is always the most important pursuit of analytical chemists. In this study, a new sample preparation procedure, namely the shaker cup (SH) method, was designed and compared with two sample preparation procedures, commonly used in the laboratory, from three aspects: homogeneity of the sample–flux mixture, potential for sample contamination, and sample preparation time. For the three methods, a set of 54 certified reference materials (CRMs) was used to establish the calibration curves, while another set of 19 CRMs was measured to validate the results. In the calibration procedures, the matrix effects were corrected using the theoretical alpha coefficient method combined with the experimental coefficient method. The data of the major oxides (SiO2, TiO2, Al2O3, TFe2O3, MnO, MgO, CaO, Na2O, K2O, and P2O5) and minor elements (Cr, Cu, Ba, Ni, Sr, V, Zr, and Zn) obtained by wavelength dispersive X-ray fluorescence spectroscopy (WD-XRF) were compared using two derivative equations based on the findings by Laurence Whitty-Léveillé. The results revealed that the WD-XRF measured values using the SH method best agreed with the values recommended in the literature.

ANALYSIS OF COBALT AND NICKEL BASES CATHODES BY X-RAY FLUORESCENCE SPECTROSCOPY

2021 ◽  
pp. 103-111
Author(s):  
A.V. Alekseev ◽  
◽  
G.V. Orlov ◽  
P.S. Petrov ◽  
◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Emission Spectroscopy ◽  
High Resolution Mass Spectrometry ◽  
Analytical Signal ◽  
Atomic Emission ◽  
X Ray ◽  
Fundamental Parameters ◽  
The Matrix ◽  
Resolution Mass ◽  
Cobalt And Nickel

In this work, Al, Cr, Cu, Fe, Ni, Si and Y were determined in SDP-6 cathodes based on cobalt and SDP-1 and AZh8 nickel-based cathodes by x-ray fluorescence spectroscopy. The calibration dependences are corrected taking into account the superposition of signals from interfering elements on the analytical signal and changes in intensity caused by inter-element influences in the matrix. A standard-free analysis was carried out using the method of fundamental parameters. The correctness of the results obtained was confirmed by a comparative analysis by atomic emission spectroscopy and high-resolution mass spectrometry with a glow discharge.

Lateral resolution of the electron microbeam analysis

1978 ◽  
Vol 36 (1) ◽  
pp. 542-543
Author(s):  
H.J. Dudek
Keyword(s):  
Quantitative Analysis ◽  
Depth Resolution ◽  
Lateral Resolution ◽  
Cylindrical Particle ◽  
Correction Procedure ◽  
X Ray ◽  
Element Concentrations ◽  
Microbeam Analysis ◽  
The Matrix

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S

Analysis and lattice imaging of a transitional event on garnets

1978 ◽  
Vol 36 (1) ◽  
pp. 270-271
Author(s):  
J.Y. Laval
Keyword(s):  
Yttrium Iron Garnet ◽  
Reciprocal Lattice ◽  
Transitional Zone ◽  
Lattice Imaging ◽  
Yttrium Iron ◽  
X Ray ◽  
Ionic Process ◽  
The Matrix ◽  
High Resolution Technique ◽  
Iron Garnet

The exsolution of magnetite from a substituted Yttrium Iron Garnet, containing an iron excess may lead to a transitional event. This event is characterized hy the formation of a transitional zone at the center of which the magnetite nucleates (Fig.1). Since there is a contrast between the matrix and these zones and since selected area diffraction does not show any difference between those zones and the matrix in the reciprocal lattice, it is of interest to analyze the structure of the transitional zones.By using simultaneously different techniques in electron microscopy, (oscillating crystal method microdiffraction and X-ray microanalysis)one may resolve the ionic process corresponding to the transitional event and image this event subsequently by high resolution technique.

Phase identification in SiC whisker reinforced Al2O3-R2O3-based composites

1992 ◽  
Vol 50 (1) ◽  
pp. 152-153
Author(s):  
C.M. Sung ◽  
K.J. Ostreicher ◽  
M.L. Huckabee ◽  
S.T. Buljan
Keyword(s):  
Analytical Electron Microscopy ◽  
Phase Identification ◽  
Reinforced Composites ◽  
Ion Milling ◽  
X Ray ◽  
Binary Oxides ◽  
Analytical Electron ◽  
The Matrix ◽  
Second Phases ◽  
Convergent Beam

A series of binary oxides and SiC whisker reinforced composites both having a matrix composed of an α-(Al, R)2O3 solid solution (R: rare earth) have been studied by analytical electron microscopy (AEM). The mechanical properties of the composites as well as crystal structure, composition, and defects of both second phases and the matrix were investigated. The formation of various second phases, e.g. garnet, β-Alumina, or perovskite structures in the binary Al2O3-R2O3 and the ternary Al2O3-R2O3-SiC(w) systems are discussed.Sections of the materials having thicknesses of 100 μm - 300 μm were first diamond core drilled. The discs were then polished and dimpled. The final step was ion milling with Ar+ until breakthrough occurred. Samples prepared in this manner were then analyzed using the Philips EM400T AEM. The low-Z energy dispersive X-ray spectroscopy (EDXS) data were obtained and correlated with convergent beam electron diffraction (CBED) patterns to identify phase compositions and structures. The following EDXS parameters were maintained in the analyzed areas: accelerating voltage of 120 keV, sample tilt of 12° and 20% dead time.

Improving x-ray map resolution with image restoration techniques

1996 ◽  
Vol 54 ◽  
pp. 598-599
Author(s):  
Richard B. Mott ◽  
John J. Friel ◽  
Charles G. Waldman
Keyword(s):  
Image Restoration ◽  
Hubble Space Telescope ◽  
Extensive Literature ◽  
Small Object ◽  
X Rays ◽  
X Ray ◽  
Mapping Parameters ◽  
The Matrix ◽  
The 1960S ◽  
Map Resolution

X-rays are emitted from a relatively large volume in bulk samples, limiting the smallest features which are visible in X-ray maps. Beam spreading also hampers attempts to make geometric measurements of features based on their boundaries in X-ray maps. This has prompted recent interest in using low voltages, and consequently mapping L or M lines, in order to minimize the blurring of the maps.An alternative strategy draws on the extensive work in image restoration (deblurring) developed in space science and astronomy since the 1960s. A recent example is the restoration of images from the Hubble Space Telescope prior to its new optics. Extensive literature exists on the theory of image restoration. The simplest case and its correspondence with X-ray mapping parameters is shown in Figures 1 and 2.Using pixels much smaller than the X-ray volume, a small object of differing composition from the matrix generates a broad, low response. This shape corresponds to the point spread function (PSF). The observed X-ray map can be modeled as an “ideal” map, with an X-ray volume of zero, convolved with the PSF. Figure 2a shows the 1-dimensional case of a line profile across a thin layer. Figure 2b shows an idealized noise-free profile which is then convolved with the PSF to give the blurred profile of Figure 2c.

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