Measurement And Simulation Of X-Ray Emission From Multilayered Structures In Electron Probe Microanalysis.

Studies of x-ray emission from thin films on substrates using an electron probe microanalyzer (EPMA) provide useful information on the characteristics of x-ray generation by electron beams. In this study, EPMA measurements of multilayered samples were performed in order to test and improve analytical and numerical models used for quantitative EPMA. These models provide relatively accurate results for samples consisting of layers with similar average atomic numbers, because of their similar properties regarding electron transport and x-ray generation. On the contrary, these models find difficulties to describe the process when the various layers have very different atomic numbers. In a previous work, we studied the surface ionization of thin copper films of various thicknesses deposited on substrates with very different atomic numbers. In the present communication, the study is extended to the case of multilayered specimens.The studied specimens consisted of thin copper films deposited on a carbon layer which, in turn, was placed on a variety of single-element substrates, ranging from Be to Bi.

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Quantitative EPMA of nitrogen : A tricky element in the electron-probe microanalyzer

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100132741 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1622-1623

Author(s):

G.F. Bastin ◽

H.J.M. Heijligers

Keyword(s):

Background Subtraction ◽

Electron Probe ◽

Detection System ◽

Higher Order ◽

Light Elements ◽

Strong Suppression ◽

Electron Probe Microanalyzer ◽

Quantitative Epma ◽

Peak Count ◽

Lead Stearate

Among the ultra-light elements B, C, N, and O nitrogen is the most difficult element to deal with in the electron probe microanalyzer. This is mainly caused by the severe absorption that N-Kα radiation suffers in carbon which is abundantly present in the detection system (lead-stearate crystal, carbonaceous counter window). As a result the peak-to-background ratios for N-Kα measured with a conventional lead-stearate crystal can attain values well below unity in many binary nitrides . An additional complication can be caused by the presence of interfering higher-order reflections from the metal partner in the nitride specimen; notorious examples are elements such as Zr and Nb. In nitrides containing these elements is is virtually impossible to carry out an accurate background subtraction which becomes increasingly important with lower and lower peak-to-background ratios. The use of a synthetic multilayer crystal such as W/Si (2d-spacing 59.8 Å) can bring significant improvements in terms of both higher peak count rates as well as a strong suppression of higher-order reflections.

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Use of the Disk-of-least-confusion in X-ray Microanalysis

Microscopy and Microanalysis ◽

10.1017/s1431927600021498 ◽

1998 ◽

Vol 4 (S2) ◽

pp. 274-275

Author(s):

E. A. Kenik ◽

S. X. Ren

Keyword(s):

Spatial Resolution ◽

Electron Scattering ◽

Electron Probe ◽

X Rays ◽

High Brightness ◽

X Ray ◽

Electron Sources ◽

Probe Diameter ◽

Electron Probe Microanalyzer ◽

Subsequent Emission

Whereas the spatial resolution for standard secondary electron (SEI) imaging in a scanning electron microscope or electron probe microanalyzer is related to the incident probe diameter, the spatial resolution for x-ray microanalysis is related to the convolution of the probe diameter with the spatial extent of the analyzed volume for a point probe. The latter is determined by electron scattering in the specimen and the subsequent emission of excited x-rays from the specimen. As such, it is possible that “What you see is not what you get”. This is especially true for instruments with high brightness electron sources (field emission). This problem is compounded by probe aberrations which at Gaussian image focus can produce significant electron tails extending tens of microns from the center of the probe.

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Hitachi Model XMA-5 Electron Probe Microanalyzer

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101281 ◽

1968 ◽

Vol 26 ◽

pp. 308-309

Author(s):

Tomura ◽

Okano ◽

Hara

Keyword(s):

Electron Probe ◽

High Performance ◽

List Type ◽

X Rays ◽

Type Number ◽

Fluorescence Excitation ◽

X Ray ◽

Electron Probe Microanalyzer ◽

Scientific Instrumentation ◽

Made In

The recent advancement in scientific instrumentation has been phenomenal. This is particularity true in the electron probe microanalyzer field. This paper describes the improvements made in the Hitachi Model XMA-5 Electron Probe Microanalyzer to achieve high performance.1.X-ray spectroscopy1-1.It is now possible to analyze a wide variety of elements including ultra light elements in minute concentrations with the advent of an increasing number of dispersing elements and high detectability.1-2.A linear crystal drive and direct wavelength read-out (with respect to the crystal) is employed in the spectrometer to assure simultaneous analyses of up to three elements by using three of the six crystals provided. For correction of absorbed X-rays and fluorescence excitation and with due consideration of the angular distribution of the characteristic X-rays, an X-ray take off angle of 38° (electron probe is incident vertically on the specimen surface) was adopted.

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The X-Ray Spectrographic Analysis of Thin Films by the Milliprobe Technique

Advances in X-ray Analysis ◽

10.1154/s0376030800001828 ◽

1961 ◽

Vol 5 ◽

pp. 512-515 ◽

Cited By ~ 2

Author(s):

Robert D. Sloan

Keyword(s):

Thin Films ◽

Electron Beam ◽

Electron Probe ◽

Spectrographic Analysis ◽

X Ray ◽

Electron Probe Microanalyzer ◽

Bulk Production

AbstractFrequently it is desirable to perform an X-ray spectrographic analysis on an area of a specimen which is considerably smaller than that normally irradiated in bulk-production spectrographs. Ideally, one would turn to an electron-beam microanalyzer for this type of analysis. Unfortunately, there are few of us who can justify the expenditure necessary to equip our laboratories with this instrument. Therefore, a compromise measure has been arrived at which permits the analyst to examine an area many magnitudes smaller than that obtainable from production spectrographs and many magnitudes less expensive than that encountered in electron-probe microanalyzer instrumentation.

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Correction for Non-Linearity of Proportional Counter Systems in Electron Probe X-Ray Microanalysis

Advances in X-ray Analysis ◽

10.1154/s0376030800003554 ◽

1965 ◽

Vol 9 ◽

pp. 208-220 ◽

Cited By ~ 3

Author(s):

Kurt F. J. Heinrich ◽

Donald Vieth ◽

Harvey Yakowitz

Keyword(s):

Theoretical Basis ◽

Electron Probe ◽

Dead Time ◽

Pulse Height ◽

The Other ◽

Time Effects ◽

X Ray ◽

Electron Probe Microanalyzer ◽

Intensity Measurements

AbstractWhile the theoretical basis for the correction of non-linearity of detector systems is well known, methods for the determination of dead-time effects must be adapted to electron probe microanalyzer systems. Two such methods, one employing both X-ray and current measurements and the other employing simultaneous X-ray measurements on two spectrometers, are described. The effect of pulse-height shrinkage at high counting rates on the linearity of the detector system is discussed. When the proposed corrections for the dead-time of X-ray detector systems employing proportional counters are applied to the X-ray intensity measurements obtained with the electron probe microanalyzer, count rates as high as 50,000 counts/sec can be used.

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Use of the Soft X-Ray Spectrograph and the Electron-Probe Microanalyzer for Determination of Elements Carbon Through Iron in Minerals and Rocks

Advances in X-ray Analysis ◽

10.1154/s0376030800003785 ◽

1965 ◽

Vol 9 ◽

pp. 487-503

Author(s):

A. K. Baird ◽

D. H. Zenger

Keyword(s):

High Precision ◽

Electron Probe ◽

Bulk Composition ◽

Major Elements ◽

Major Constituent ◽

X Ray ◽

Electron Probe Microanalyzer ◽

Minor Elements ◽

Combined Use ◽

Sodium Magnesium

AbstractThe major elements m common rocks are of low atomic number, but analyses of high precision are possible by soft X-ray spectrography if several grams of rock sample are available. The electron-probe microanalyzer is shown to complement this established method by permitting analyses of particles as small as 1 μ in diameter. This paper describes applications of these methods to the analysis of the major and minor elements of silicate, carbonate, and phosphate minerals and rocks.Elements of particular interest are as follows : carbon in particles enclosed in carbonate rocks; oxygen, as the major constituent of the specimens; phosphorus in phosphatic nodules and apatites; manganese and iron, as colorations in fossil shells; and the group oxygen, sodium, magnesium, aluminum, silicon, potassium, calcium, and iron as complex segregations and zonations within single crystals of several mineral phases.If the bulk composition of a rock is known, and also the chemistry of the constituent minerals, it is possible to compute quantitative minéralogie analyses of high precision. Thus, the combined use of soft X-ray spectrography and electronprobe microanalysis can provide quantitative chemical and mineralogicat information on the earth's crust on all scales from thousands of square miles (by means of appropriate sampling) down to the scale of 1 μ.

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