Thermal Effects During Low-Voltage Electron-Probe X-Ray Spectral Microanalysis with Nanometer Localization

2017 ◽  
Vol 59 (10) ◽  
pp. 1061-1064 ◽  
Author(s):  
A. Yu. Kuzin ◽  
M. A. Stepovich ◽  
V. B. Mityukhlyaev ◽  
P. A. Todua ◽  
M. N. Filippov
Keyword(s):  
Thermal Effects ◽  
Electron Probe ◽  
Low Voltage ◽  
X Ray ◽  
Voltage Electron

Change in the Chemical Composition of an Analyzed Object During Low-Voltage Electron Probe X-Ray Spectral Microanalysis

2017 ◽  
Vol 59 (11) ◽  
pp. 1234-1237
Author(s):  
A. Yu. Kuzin ◽  
V. B. Mityukhlyaev ◽  
P. A. Todua ◽  
M. N. Filippov
Keyword(s):  
Chemical Composition ◽  
Electron Probe ◽  
Low Voltage ◽  
X Ray ◽  
Voltage Electron

Low-Voltage Electron-Probe Microanalysis of Fe–Si Compounds Using Soft X-Rays

2013 ◽  
Vol 19 (6) ◽  
pp. 1698-1708 ◽  
Author(s):  
Phillip Gopon ◽  
John Fournelle ◽  
Peter E. Sobol ◽  
Xavier Llovet
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Low Voltage ◽  
Mass Attenuation Coefficient ◽  
X Rays ◽  
X Ray ◽  
Voltage Electron ◽  
Increased Sensitivity ◽  
Quantitative Analyses ◽  
Areas Of Interest

AbstractConventional electron-probe microanalysis has an X-ray analytical spatial resolution on the order of 1–4 μm width/depth. Many of the naturally occurring Fe–Si compounds analyzed in this study are smaller than 1 μm in size, requiring the use of lower accelerating potentials and nonstandard X-ray lines for analysis. Problems with the use of low-energy X-ray lines (soft X-rays) of iron for quantitative analyses are discussed and a review is given of the alternative X-ray lines that may be used for iron at or below 5 keV (i.e., accelerating voltage that allows analysis of areas of interest <1 μm). Problems include increased sensitivity to surface effects for soft X-rays, peak shifts (induced by chemical bonding, differential self-absorption, and/or buildup of carbon contamination), uncertainties in the mass attenuation coefficient for X-ray lines near absorption edges, and issues with spectral resolution and count rates from the available Bragg diffractors. In addition to the results from the traditionally used Fe Lα line, alternative approaches, utilizing Fe Lβ, and Fe Ll-η lines, are discussed.

Electron Probe Microanalysis Through Coated Oxidized Surfaces

2019 ◽  
Vol 25 (05) ◽  
pp. 1112-1129 ◽  
Author(s):  
Mike B. Matthews ◽  
Ben Buse ◽  
Stuart L. Kearns
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Low Voltage ◽  
Layer Structure ◽  
Oxide Thickness ◽  
Linear Functions ◽  
Voltage Electron ◽  
Before And After ◽  
20 Nm ◽  
Good Agreement

AbstractLow voltage electron probe microanalysis (EPMA) of metals can be complicated by the presence of a surface oxide. If a conductive coating is applied, analysis becomes one of a three-layer structure. A method is presented which allows for the coating and oxide thicknesses and the substrate intensities to be determined. By restricting the range of coating and oxide thicknesses, tc and to respectively, x-ray intensities can be parameterized using a combination of linear functions of tc and to. tc can be determined from the coating element k-ratio independently of the oxide thickness. to can then be derived from the O k-ratio and tc. From tc and to the intensity components of the k-ratios from the oxide layer and substrate can each be derived. Modeled results are presented for an Ag on Bi2O3 on Bi system, with tc and to each ranging from 5 to 20 nm, for voltages of 5–20 kV. The method is tested against experimental measurements of Ag- or C-coated samples of polished Bi samples which have been allowed to naturally oxidize. Oxide thicknesses determined both before and after coating with Ag or C are consistent. Predicted Bi Mα k-ratios also show good agreement with EPMA-measured values.

Improving the Analtical Accuracy in the Analysis of Particles by Employing Low Voltage Analysis:

2000 ◽  
Vol 6 (S2) ◽  
pp. 924-925
Author(s):  
JA Small ◽  
JT Armstrong
Keyword(s):  
Electron Beam ◽  
Electron Probe ◽  
Low Voltage ◽  
X Rays ◽  
Relative Uncertainty ◽  
Particle Volume ◽  
X Ray ◽  
Uncertainty Estimates ◽  
Corrected Data ◽  
Particle Geometry

The energy of the electron beam, in conventional electron probe microanalysis, is generally in the range of 15-25 keV which provides the necessary overvoltage to excite efficiently the K and L x-ray lines for elements with atomic numbers in the range of about 5-83. One of the primary microanalytical methods for obtaining compositional information on particles is X-ray analysis in the electron probe and these same voltage criteria have been applied to the procedures developed for this purpose. The main difference in analytical procedures for bulk samples and particles is that corrections have to be applied to the particle k-ratios or calculated compositions to compensate for: 1) the penetration or scattering of electrons out of the particle volume and 2) variations in the absorption due to particle geometry of x-rays less than about 3 keV. In general, particle corrections improve the accuracy and reduce the relative uncertainty estimates from several tens of percent for uncorrected data to about 10% for corrected data.

Minimally Invasive (ENERGY) Dispersive Analytical Spectroscopy (MIDAS). The Golden Touch for In-Situ X-Ray Microanalysis of Bulk Bio-Organic Samples

1999 ◽  
Vol 5 (S2) ◽  
pp. 574-575
Author(s):  
Patrick Echlin
Keyword(s):  
Low Voltage ◽  
Wide Spectrum ◽  
High Energy ◽  
Chemical Information ◽  
Local Concentration ◽  
Biological Investigation ◽  
X Ray ◽  
Energy Beam ◽  
Voltage Electron

The matrix of bio-organic samples is composed primarily of carbon, hydrogen, oxygen and nitrogen. Dispersed within this matrix there is a wide spectrum of other elements whose local concentration can be measured in situ by x-ray spectroscopy. The analysis continues to present a challenge because most samples are highly hydrated, beam sensitive and of low density. In light of these restrictions there is only one sensible approach to the use of an analytical procedure which depends on the intereaction of high energy beam electrons with a labile specimen. Samples must be prepared by the least invasive preparative procedure and irradiated with the minimum amount of energy in order to obtain the maximun amount of chemical information. Low temperature sample preparation and low voltage electron beam instruments are central to these processes. By way of example, a brief description will be given of an on-going biological investigation which makes full use of these processes.

scholarly journals Low-Voltage Electron-Probe Microanalysis of Uranium

2021 ◽  
pp. 1-18
Author(s):  
Mike B. Matthews ◽  
Stuart L. Kearns ◽  
Ben Buse
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Low Voltage ◽  
Voltage Electron

Abstract

Modifying a low-voltage electron probe system

2014 ◽  
Vol 78 (9) ◽  
pp. 821-825 ◽  
Author(s):  
V. V. Kazmiruk ◽  
I. G. Kurganov ◽  
T. N. Savitskaya
Keyword(s):  
Electron Probe ◽  
Low Voltage ◽  
Voltage Electron ◽  
Probe System

Improvements in the electron probe forming capabilities and x-ray hole counts in the Philips TEM

1983 ◽  
Vol 41 ◽  
pp. 376-377
Author(s):  
Richard L. McConville
Keyword(s):  
Field Strength ◽  
Electron Probe ◽  
Spherical Aberration ◽  
Focal Length ◽  
Objective Lens ◽  
Parallel Beam ◽  
Tilt Axis ◽  
X Ray ◽  
Small Probe ◽  
Specimen Height

A second generation twin lens has been developed. This symmetrical lens with a wider bore, yet superior values of chromatic and spherical aberration for a given focal length, retains both eucentric ± 60° tilt movement and 20°x ray detector take-off angle at 90° to the tilt axis. Adjust able tilt axis height, as well as specimen height, now ensures almost invariant objective lens strengths for both TEM (parallel beam conditions) and STEM or nano probe (focused small probe) modes.These modes are selected through use of an auxiliary lens situ ated above the objective. When this lens is on the specimen is illuminated with a parallel beam of electrons, and when it is off the specimen is illuminated with a focused probe of dimensions governed by the excitation of the condenser 1 lens. Thus TEM/STEM operation is controlled by a lens which is independent of the objective lens field strength.

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