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.

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

Improved in-lens low-loss electron detector for the Scanning Electron Microscope

1991 ◽  
Vol 49 ◽  
pp. 480-481
Author(s):  
Oliver C. Wells ◽  
Eric Munro
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Beam Energy ◽  
High Field ◽  
Incident Beam ◽  
Objective Lens ◽  
Low Loss ◽  
Incident Beam Energy ◽  
The Magnetic Field ◽  
Scanning Electron

We have built an improved version of in-lens low-loss electron (LLE) detector for the scanning electron microscope (SEM) in which the LLE are energy-filtered by the focusing field. The sample is in the high-field region of a condenser-objective lens (Fig. 1). The fastest scattered electrons are then confined by the magnetic field of the lens into a region with a well-defined outer surface (Fig. 1(b)). A detector is moved under micrometer control to be just inside this surface. In this way, only the fastest scattered electrons (which are the LLE) are collected. In the earlier work, the detector was a flat aluminized garnet scintillator. This showed that the method did work but required that the incident beam energy E0 should be greater than the energy threshold of the scintillator.

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).

Recording of electron-diffraction patterns of radiation-sensitive materials in the high-voltage electron microscope with luminescent radiographic screens

1977 ◽  
Vol 10 (1) ◽  
pp. 62-63 ◽  
Author(s):  
M. V. King ◽  
D. F. Parsons
Keyword(s):  
Electron Microscope ◽  
Electron Diffraction ◽  
Visible Light ◽  
High Voltage ◽  
Enhancement Ratio ◽  
X Ray ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Diffraction Patterns

An effective method for greatly reducing the electron exposure of radiation-sensitive organic or biological specimens while recording their diffraction patterns in a high-voltage (MeV range) electron microscope is described. It involves recording on double-coated screen-type medical X-ray film and backing it with a luminescent radiographic screen which intercepts the transmitted electrons and emits visible light that exposes the bottom emulsion of the film. Values of sensitivity, resolution, and enhancement ratio are tabulated: the latter values range up to 41. Typical patterns taken with l-valine are shown.

Instrumentation for detecting channelling radiation in the high-voltage electron microscope

1983 ◽  
Vol 41 ◽  
pp. 318-319
Author(s):  
J. H. Butler ◽  
C. J. Humphreys
Keyword(s):  
Monochromatic Light ◽  
Incident Beam ◽  
Laboratory Frame ◽  
Relativistic Electrons ◽  
Voltage Electron ◽  
Dipole Emission ◽  
Sinusoidal Oscillations ◽  
Pass Through ◽  
Incident Beam Energy ◽  
Increasing Function

Electromagnetic radiation is emitted when fast (relativistic) electrons pass through crystal targets which are oriented in a preferential (channelling) direction with respect to the incident beam. In the classical sense, the electrons perform sinusoidal oscillations as they propagate through the crystal (as illustrated in Fig. 1 for the case of planar channelling). When viewed in the electron rest frame, this motion, a result of successive Bragg reflections, gives rise to familiar dipole emission. In the laboratory frame, the radiation is seen to be of a higher energy (because of the Doppler shift) and is also compressed into a narrower cone of emission (due to the relativistic “searchlight” effect). The energy and yield of this monochromatic light is a continuously increasing function of the incident beam energy and, for beam energies of 1 MeV and higher, it occurs in the x-ray and γ-ray regions of the spectrum. Consequently, much interest has been expressed in regard to the use of this phenomenon as the basis for fabricating a coherent, tunable radiation source.

A New 1000kv Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 100-101
Author(s):  
J.L. Williams ◽  
K. Heathcote ◽  
E.J. Greer
Keyword(s):  
Electron Microscope ◽  
Direct Observation ◽  
High Voltage ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Specimen Thickness ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
Dynamic Experiments ◽  
Conventional Instrument

High Voltage Electron Microscope already offers exciting experimental possibilities to Biologists and Materials Scientists because the increased specimen thickness allows direct observation of three dimensional structure and dynamic experiments on effectively bulk specimens. This microscope is designed to give maximum accessibility and space in the specimen region for the special stages which are required. At the same time it provides an ease of operation similar to a conventional instrument.

A New 1,000 kV Electron Microscope

1967 ◽  
Vol 25 ◽  
pp. 260-261
Author(s):  
M. Nishigaki ◽  
S. Katagiri ◽  
H. Kimura ◽  
B. Tadano
Keyword(s):  
Electron Microscope ◽  
High Voltage ◽  
Basic Research ◽  
Chromatic Aberration ◽  
High Accuracy ◽  
Biological Specimen ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron

The high voltage electron microscope has many advantageous features in comparison with the ordinary electron microscope. They are a higher penetrating efficiency of the electron, low chromatic aberration, high accuracy of the selected area diffraction and so on. Thus, the high voltage electron microscope becomes an indispensable instrument for the metallurgical, polymer and biological specimen studies. The application of the instrument involves today not only basic research but routine survey in the various fields. Particularly for the latter purpose, the performance, maintenance and reliability of the microscope should be same as those of commercial ones. The authors completed a 500 kV electron microscope in 1964 and a 1,000 kV one in 1966 taking these points into consideration. The construction of our 1,000 kV electron microscope is described below.

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

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