A robust method for determining the Duane-Hunt energy limit from EDS

1990 ◽  
Vol 48 (2) ◽  
pp. 210-211
Author(s):  
Robert L. Myklebust ◽  
Charles E. Fiori ◽  
Dale E. Newbury
Keyword(s):  
Electron Probe ◽  
Beam Energy ◽  
Potential Drop ◽  
Matrix Correction ◽  
Energy Limit ◽  
Energy Excitation ◽  
X Ray ◽  
Beam Voltage ◽  
Lower Beam ◽  
Quantitative Electron Probe Microanalysis

The electron beam energy is a parameter required for quantitative electron probe microanalysis. In fact, it occurs in all parts of the ZAF type matrix correction procedure as well as in all of the other matrix correction procedures. Recently, there has been much interest in analyzing materials using lower beam voltages. Since the correction procedures use the so called “overvoltage” term (beam energy/excitation energy), uncertainties in the beam voltage will generate larger errors than when high beam voltages are used. The user may well be faced with an instrument that does not have a very precise voltmeter to measure the beam voltage, or the reported voltage may not actually represent the potential drop from the filament to ground (specimen). The true beam energy may differ from the “measured” potential drop by several hundred volts.It is difficult and potentially exciting to measure the beam voltage with a calibrated voltmeter; however, we have a built-in method available in the energy-dispersive x-ray detector.

Embracing Uncertainty: Modeling Uncertainty in EPMA—Part II

2021 ◽  
Vol 27 (1) ◽  
pp. 74-89
Author(s):  
Nicholas W.M. Ritchie
Keyword(s):  
Beam Energy ◽  
Uncertainty Modeling ◽  
Matrix Correction ◽  
Correction Model ◽  
X Ray ◽  
Starting Point ◽  
Uncertainty Calculation ◽  
The Matrix ◽  
Measurement Design ◽  
New Framework

AbstractThis, the second in a series of articles present a new framework for considering the computation of uncertainty in electron excited X-ray microanalysis measurements, will discuss matrix correction. The framework presented in the first article will be applied to the matrix correction model called “Pouchou and Pichoir's Simplified Model” or simply “XPP.” This uncertainty calculation will consider the influence of beam energy, take-off angle, mass absorption coefficient, surface roughness, and other parameters. Since uncertainty calculations and measurement optimization are so intimately related, it also provides a starting point for optimizing accuracy through choice of measurement design.

Measurement and parameterization of ϕ(ρz) curves for quantitative electron probe microanalysis

1990 ◽  
Vol 48 (2) ◽  
pp. 190-191
Author(s):  
J. D. Brown
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Absorption Coefficients ◽  
Computing Power ◽  
X Ray ◽  
Practical Applications ◽  
Absorption Correction ◽  
Exponential Decrease ◽  
Quantitative Electron Probe Microanalysis ◽  
Z Curve

The goal of correction methods for quantitative electron probe microanalysis is to convert k-ratios for any type of specimen, any x-ray line and all electron beam energies into accurate concentrations. Early attempts to approach this goal were hindered by sparse data on electron interactions with solids, limited knowledge of x-ray parameters such as mass absorption coefficients and limited computing power which made necessary mathematical simplifications in practical applications.In developing the early models for quantitative analysis, the argument was made that the absorption correction was insensitive to the shape of the ϕ(ρz) curve. For that reason, a number of very crude models which ranged from constant x-ray generation as a function of depth(l) to an exponential decrease from the surface(2) were used. In fact, these models worked quite well for the restricted conditions for which they were designed but of course lack accuracy when applied to more general situations. ϕ(ρz) measurements

scholarly journals Analysis the influence of pulse-to-pulse stability of modulator on high-power microwave output of pulsed klystron

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yongfang Liu ◽  
Hiroshi Matsumoto ◽  
Lin Li ◽  
Ming Gu
Keyword(s):  
High Power ◽  
Free Electron ◽  
Free Electron Laser ◽  
Linear Accelerator ◽  
Beam Energy ◽  
Electron Linear Accelerator ◽  
X Ray ◽  
Voltage Instability ◽  
Beam Voltage ◽  
The Stability

AbstractX-ray free electron laser (XFEL) facility based on electron linear accelerator (LINAC) is regarded as one kind of the fourth-generation light source with the characteristics of high intensity, exceptional brightness, ultrashort pulse duration, and spatial coherence. In electron linear accelerator, energy of beam bunches is provided by high-power electromagnetic microwaves which are generated by a microwave tube called klystron. The stability of beam voltage of klystron occupies a key position in both the stability of output RF (Radio Frequency) power and the jitter of output RF phase, furthermore, it plays an extremely important role in beam energy stability of electron linear accelerator. In this paper, high power RF fluctuation and phase jitter of klystron output caused by beam voltage instability of klystron are analyzed and calculated. Influence of klystron beam voltage instability on beam energy gain in linear accelerator have also been further analyzed and calculated. The calculating procedure is particularly valuable for us to understand the relationship between pulse modulator stability and beam energy gain fluctuations. Finally, relevant experimental results measured by Shanghai Soft X-ray Free Electron Laser Test Facility (SXFEL-TF) is presented.

EPMA of submicron coatings containing ultralight elements

1992 ◽  
Vol 50 (2) ◽  
pp. 1628-1629
Author(s):  
Peter Willich
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Analytical Sensitivity ◽  
X Ray ◽  
Quantitative Electron Probe Microanalysis ◽  
X Ray Absorption ◽  
Primary Electrons ◽  
Critical Excitation

Materials containing ultralight elements (B, C, N, O) in combination with a metal are of considerable interest in thin film technology. Quantitative electron probe microanalysis of the coatings should be independent of the substrate and has to be carried out under the condition that the ultimate depth of x-ray emission (Rx) is within the provided film thickness of 0.2-0.8 μm. Rx, for an element (critical excitation energy Ec) in a specified matrix is controlled by the energy (E0) of the primary electrons. EPMA of high atomic number elements (Ec = 2-7 keV), under the condition of Rx < 1 μm, frequently requires operation at a low overvoltage of E0/Ec < 2. Consequendy, tne x-ray intensities are very low and the analytical sensitivity is drastically reduced. For the ultralight elements the strong effects oft x-ray absorption always lead to a shallow depth of x-ray emission, even at a high overvoltage.

Quantitative Electron Probe Microanalysis of Nonconducting Specimens: Science or Art?

2004 ◽  
Vol 10 (6) ◽  
pp. 733-738 ◽  
Author(s):  
Guillaume F. Bastin ◽  
Hans J.M. Heijligers
Keyword(s):  
Electrical Conductivity ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Light Element ◽  
X Ray ◽  
Surface Charging ◽  
Quantitative Electron Probe Microanalysis ◽  
Quantitative Analyses ◽  
Intensity Ratios ◽  
Effect Of Surface

The influence of a lack of sufficient electrical conductivity on the results of quantitative electron probe microanalysis has been investigated on a number of oxides. The effect of surface charging and the way it alters the emitted X-ray signals has been studied. It is shown that the presence of conducting coatings, such as carbon or copper, will affect the interelement X-ray intensity ratios, whatever the thickness of the coating may be. Although the effects for heavier elements may be acceptable, they cannot be ignored for a light element such as oxygen, where strong variations with coating thickness were observed. Quantitative analyses of oxygen, on uncoated well-conducting oxide specimens, using uncoated well-conducting hematite (Fe2O3) as a standard yielded excellent results in the range between 4 and 40 kV with the φ(ρz) software used. As soon as coated nonconducting specimens were examined, using the same hematite standard, coated under exactly the same conditions, widely scattering and noncoherent results were obtained. These discrepancies can only be attributed to a lack of conductivity.

Quantitative Electron Probe Microanalysis of Bi-Sr-Ca-Cu-O High Tc Superconductors Using Energy- and Wavelength-Dispersive Spectrometry

1997 ◽  
Vol 3 (6) ◽  
pp. 504-511
Author(s):  
Ryna B. Marinenko ◽  
Mark Teplitsky
Keyword(s):  
Electron Probe ◽  
Matrix Correction ◽  
Linear Least Squares ◽  
High Tc Superconductors ◽  
Spectral Processing ◽  
High Tc ◽  
Eds Analysis ◽  
Wavelength Dispersive Spectrometry ◽  
Quantitative Electron Probe Microanalysis ◽  
Quantitative Results

Abstract: Multiple linear least squares (MLLSQ) and sequential simplex spectral processing procedures were used in an electron probe energy-dispersive (EDS) analysis of a 2223 Bi-Sr-Ca-Cu-O (BSCCO) high Tc superconductor specimen. This phase is normally difficult to quantify by EDS at voltages below 25 kV because of the severe overlap of the BiM lines with the M lines from a small amount of Pb that is added to the phase for stability. Quantitative results from the MLLSQ spectral processing and ZAF matrix correction procedures agreed well with wavelength-dispersive analysis (WDS) of the same specimen.

Basic literacy in electron-probe x-ray microanalysis with energy-dispersive x-ray spectrometry: Qualitative and quantitative analysis

1994 ◽  
Vol 52 ◽  
pp. 384-385
Author(s):  
Dale E. Newbury
Keyword(s):  
Quantitative Analysis ◽  
Qualitative Analysis ◽  
Electron Probe ◽  
Beam Energy ◽  
Incident Beam ◽  
Energy Dispersive ◽  
Photon Detection ◽  
X Ray ◽  
Entire Energy Range ◽  
Incident Beam Energy

Rigorous electron probe x-ray microanalysis (EPMA) with energy dispersive x-ray spectrometry (EDS) takes place in two sequential steps: qualitative analysis followed by quantitative analysis.Qualitative analysis: Qualitative analysis involves the assignment of the peaks found in the x-ray spectrum to specific elements. One of the most important attributes of energy dispersive x-ray spectrometry (EDS) for qualitative analysis is that we can always view the complete x-ray spectrum. The EDS photon detection process effectively provides parallel detection in energy. Depending on the detector window and spectrometer characteristics, the entire energy range from Be K radiation (0.106 keV) to the incident beam energy can be available for analysis. With an incident beam energy of 15 keV, at least one family of x-ray lines (K, L, or M shell) will be excited for each element in the Periodic Table with atomic number ≥ 4. We ignore at our peril this capability to do a complete qualitative analysis at all specimen locations that we choose to measure. Quantitative analysis is meaningless if qualitative analysis has not been properly perfonned first. The bases for qualitative analysis include the exact energy of the peak(s), which places a premium on spectrometer calibration, the recognition of all members of each x-ray family and the possibility of two (or more) families being excited, the relative intensities ("weights of lines") within a family, and the artifacts associated with each high intensity peak, particularly the escape peak(s) and sum peak(s).

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