The effect of some instrument operating conditions on the x‐ray microanalysis of particles in the environmental scanning electron microscope

Abstract

Summary:The objective of this investigation was to evaluate the practical effects of electron beam broadening in the environmental scanning electron microscope (ESEM) on particle x-ray microanalysis and to determine some of the optimum operating conditions for this type of analysis. Four sets of experiments were conducted using a Faraday cage and particles of copper, glass, cassiterite, and rutile. The accelerating voltage and chamber pressure varied from 20 to 10 kV and from 665-66 Pa (5.0 to 0.5 torr), respectively. The standard gaseous secondary electron detectors (GSED) and the long environmental secondary dectectors (ESD) for the ESEM were evaluated at different working distances. The effect of these parameters on the presence of artifact peaks was evaluated. The particles were mounted on carbon tape on an aluminum specimen mount and were analyzed individually and as a mixture. Substrate peaks were present in almost all of the spectra. The presence of neighboring particle peaks and the number of counts in these depended upon the operating conditions. In general, few of these peaks were observed with the long ESD detector at 19 mm working distance and at low chamber pressures. More peaks and counts were observed with a deviation from these conditions. The most neighboring peaks and counts were obtained with the GSED detector at 21.5 mm working distance, 10 kV accelerating voltage, and 665 Pa (5.0 torr) chamber pressure. The results of these experiments support the idea that the optimum instrumental operating conditions for EDS analysis in the ESEM occur by minimizing the gas path length and the chamber water vapor pressure, and by maximizing the accelerating voltage. The results suggest that the analyst can expect x-ray counts from the mounting materials. These tests strongly support the recommendation of the manufacturer to use the long ESD detector and a 19 mm working distance for EDS analysis. The results of these experiments indicate that neighboring particles millimeters from the target may contribute x-ray counts to the spectrum.

Additive Manufacturing of Zn‐Doped ZrO2Architectures

“…[ 44 ] The peak at 1.5 keV (Al Kα 1,2 and Kβ 1 ) is associated with the stray radiation from the aluminum SEM specimen stub. [ 44,45 ] The atomic percentages of Zn are estimated for the doped architectures, based on the Zr Lα and Zn Kα signals, excluding other contributions, and are 1.1 ± 0.1, 2.5 ± 0.1, and 4.9 ± 0.1 for ZrO 2 :Zn1, ZrO 2 :Zn2.5, and ZrO 2 :Zn5 annealed at 600 °C. [ 44 ]…”

Quantitative Determination of Low-ZElements in Single Atmospheric Particles on Boron Substrates by Automated Scanning Electron Microscopy−Energy-Dispersive X-ray Spectrometry

“…Working under high-vacuum is desirable for particle microanalysis but is not strictly speaking nondestructive compared with low-vacuum SEM. 49 The use of a cryogenic (nitrogen-cooled) stage can delay volatilization 38 but is not implemented with the SEM used in this study. Although Peltier-cooled devices enable the temperature to decrease down to -50 °C, their use has not yet proven successful for beam-sensitive particle analysis.…”

“…The amplitude of the beam damage effect can be reduced by optimizing the measuring conditions. Working under high-vacuum is desirable for particle microanalysis but is not strictly speaking nondestructive compared with low-vacuum SEM . The use of a cryogenic (nitrogen-cooled) stage can delay volatilization 38 but is not implemented with the SEM used in this study.…”

Interfacial Energy-Dispersive Spectroscopy Profile X-Ray Resolution Measurements in Variable Pressure SEM

“…As a consequence, these additional contributions affect the signal-to-spurious intensity ratio and the EDS spectrum quality. Numerous works have been published studying the complication imposed by the beam skirting that can greatly alter the results achieved with X-ray microanalysis (Gilpin & Sigee, 1995; Carlton, 1996; Mathieu, 1998; Mansfield, 2000; Khouchaf & Verstraete, 2002; Khouchaf & Boinski, 2007). In order to take into account the effects of beam skirting and to overcome these limitations in EDS analysis, two categories of correction method (beam-stop and pressure-variation) have been proposed (Bilde-Sørensen & Appel, 1997; Doehne, 1997; Gauvin, 1999).…”