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).

Low Beam Energy X-Ray Micro Analysis: How Useful Is It?

1997 ◽  
Vol 3 (S2) ◽  
pp. 881-882 ◽  
Author(s):  
Dale E. Newbury
Keyword(s):  
Electron Beam ◽  
Beam Energy ◽  
Strong Dependence ◽  
Incident Beam ◽  
X Ray ◽  
Upper Limit ◽  
History Of ◽  
Incident Beam Energy ◽  
Micro Analysis ◽  
Electron Range

Throughout the history of electron-beam X-ray microanalysis, analysts have made good use of the strong dependence of electron range on incident energy (R ≈ E1,7) to optimize the analytical volume when attacking certain types of problems, such as inclusions in a matrix or layered specimens. The “conventional” energy range for quantitative electron beam X-ray microanalysis can be thought of as beginning at 10 keV and extending to the upper limit of the accelerating potential, typically 30 - 50 keV depending on the instrument. The lower limit of 10 keV is selected because this is the lowest incident beam energy for which there is a satisfactory analytical X-ray peak excited from the K-, L-, or M- shells (in a few cases, two shells are simultaneously excited, e.g., Fe-K and Fe-L) for every element in the Periodic Table that is accessible to X-ray spectrometry, beginning with Be (Ek =116 eV) and extending to the transuranic elements. This criterion is based upon establishing a minimum overvoltage U = E0/Ec > 1.25, which is the practical minimum for useful excitation.

X‐ray standing waves as probes of surface structure: Incident beam energy effects

1995 ◽  
Vol 78 (4) ◽  
pp. 2311-2322 ◽  
Author(s):  
Stephan Kirchner ◽  
Jin Wang ◽  
Zhijian Yin ◽  
Martin Caffrey
Keyword(s):  
Surface Structure ◽  
Beam Energy ◽  
Standing Waves ◽  
Incident Beam ◽  
X Ray ◽  
Incident Beam Energy

Some Advantages of EDS Analysis in a 400 KV Electron Microscope

1985 ◽  
Vol 62 ◽  
Author(s):  
S. Suzuki ◽  
T. Honda ◽  
Y. Bando
Keyword(s):  
Electron Microscope ◽  
Spatial Resolution ◽  
Beam Energy ◽  
Incident Beam ◽  
X Ray ◽  
Voltage Electron ◽  
Eds Analysis ◽  
High Voltage Electron Microscope ◽  
Incident Beam Energy ◽  
Better Than

ABSTRACTThe dependence of the characteristic and bremsstrahlung X-ray counts, the peak to background (P/B) ratio and the spatial resolution on the incident beam energy between 100 keV and 400 keV were measured using a high voltage electron microscope (HVEM). The bremsstrahlung count decreases much faster than that of the characteristic count with the increase of the incident beam energy. The decrease rate depends on Z number. It is ascertained that the P/B ratio and the spatial resolution at 400 keV were 2 or 3 and 2.5 times better than those at 100 keV, respectively.

Optimizing conditions for x-ray microchemical analysis in analytical electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 548-549 ◽  
Author(s):  
N. J. Zaluzec
Keyword(s):  
Solid Angle ◽  
Analytical Electron Microscopy ◽  
Incident Beam ◽  
Thin Foil ◽  
Experimental Conditions ◽  
X Ray ◽  
Microchemical Analysis ◽  
Analytical Electron ◽  
Image Position ◽  
Incident Beam Energy

The ultimate sensitivity of microchemical analysis using x-ray emission rests in selecting those experimental conditions which will maximize the measured peak-to-background (P/B) ratio. This paper presents the results of calculations aimed at determining the influence of incident beam energy, detector/specimen geometry and specimen composition on the P/B ratio for ideally thin samples (i.e., the effects of scattering and absorption are considered negligible). As such it is assumed that the complications resulting from system peaks, bremsstrahlung fluorescence, electron tails and specimen contamination have been eliminated and that one needs only to consider the physics of the generation/emission process.The number of characteristic x-ray photons (Ip) emitted from a thin foil of thickness dt into the solid angle dΩ is given by the well-known equation

Comparison of high-angle take-off and low-angle take-off EDX detector geometry of the HF-2000 FE-TEM

1993 ◽  
Vol 51 ◽  
pp. 252-253
Author(s):  
Y. Sato ◽  
T. Hashimoto ◽  
M. Ichihashi ◽  
Y. Ueki ◽  
K. Hirose ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Field Emission ◽  
Solid Angle ◽  
Energy Dispersive ◽  
Objective Lens ◽  
X Rays ◽  
High Angle ◽  
X Ray ◽  
Detector Geometry

Analytical TEMs have two variations in x-ray detector geometry, high and low angle take off. The high take off angle is advantageous for accuracy of quantitative analysis, because the x rays are less absorbed when they go through the sample. The low take off angle geometry enables better sensitivity because of larger detector solid angle.Hitachi HF-2000 cold field emission TEM has two versions; high angle take off and low angle take off. The former allows an energy dispersive x-ray detector above the objective lens. The latter allows the detector beside the objective lens. The x-ray take off angle is 68° for the high take off angle with the specimen held at right angles to the beam, and 22° for the low angle take off. The solid angle is 0.037 sr for the high angle take off, and 0.12 sr for the low angle take off, using a 30 mm2 detector.

Quantitative analysis of subcellular calcium from electron probe X-ray images

2003 ◽  
Author(s):  
J.G. Wong ◽  
B.J. Hurley ◽  
D.E. Johnson ◽  
M.E. Cantino
Keyword(s):  
Quantitative Analysis ◽  
Electron Probe ◽  
X Ray
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