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1.
The development of the microcalorimeter energy-dispersive X-ray spectrometer (µ-cal EDS) offers a significant advancement in X-ray microanalysis, especially for electron beam instruments. The benefits are especially pronounced for low voltage (5kV) X-ray microanalysis in the field emission scanning electron microscope (FE-SEM) where the high energy resolution of the µ-cal EDS minimizes the peak overlaps among the myriad of K, L, M and N lines in the 0–5keV energy range. The availability of L- and M-shell X-ray lines for microanalysis somewhat offsets the absence of X-ray lines traditionally used above 5keV energy. The benefits and challenges of the µ-cal EDS will be discussed, including P/B ratio for characteristic X-rays, collection angle, count rate capability and the impact of polycapillary X-ray optics on microanalysis. 相似文献
2.
In this study, a prototype WDS-EPMA equipped with a thermal field emitter (TFE) was used. By using X-ray mapping technique
with this instrument, we analyzed sub-micron inclusions in highly pure copper compounds used for manufacturing electronic
devices. The analytical conditions of the accelerating voltages were 10 keV and 15 keV; the measured elements were Ni and
Si. We measured 160000 points (400 × 400 points) within a couple of hours (1.5 hours at 10 keV, 0.5 hour at 15 keV). The analysis
of the X-ray mapping data revealed very small inclusions with diameters estimated to be less than 100 nm. The new EPMA could
be used for the elemental analysis of various materials including very light elements in a wide area with a spatial resolution
of 100 nm. 相似文献
3.
A homogeneous (phosphate glass) and a heterogeneous (glass ceramic) material were chosen to develop a method for electron
microprobe analysis of nitrogen in glasses and glass ceramics. The metaphosphate (50 mole-% P2O5, 25 mole-% BaO, 25 mole-% Rb2O) base glass and the silicate glass (composition of the base glass: 6.9 mole-% Al2O3, 21.3 mole-% MgO, 47.3 mole-% SiO2, 5.1 mole-% CaO, 19.4 mole-% AlN) were melted and cooled down to room temperature. In a second step, the two materials were
nitrided by applying dry NH3 in a special tube furnace. Up to 5 wt.-% of nitrogen could be introduced. The ability of energy dispersive (EDX) as well
as wavelength dispersive (WDX) electron probe microanalysis to analyze low contents of light elements in combination with
highly concentrated heavy elements was tested both for glasses and for glass ceramics. Measuring conditions had to be optimized
to get reliable analytical results as well as to avoid radiation damage of the glasses which may occur especially in the case
of wavelength dispersive X-ray analysis.
The results were compared with two different analytical methods: inductive coupled plasma analysis and a commercial nitrogen-oxygen-analyzer
(the specimen is decomposed by heating and the released gases are analyzed spectroscopically (O) and electrically (N)). 相似文献
4.
Raynald Gauvin 《Mikrochimica acta》2006,155(1-2):75-81
Monte Carlo simulations are used to obtain new results of x-ray microanalysis of sample types frequently encountered in practical
analytical situations such as a vertical layer embedded in a homogeneous matrix and a spherical particulate deposited on a
substrate. The simulations show that a 10-nm layer of boron in a steel matrix can be imaged using backscattered electrons
and detected using x-ray microanalysis with a field emission scanning electron microscope even with an electron beam energy
equals to 20 keV and also that these simulations can be useful to estimate the optimum acceleration voltage to perform such
analyses. For a carbon spherical particulate located on the top of a gold substrate, it is shown that x-ray emission and electron
backscattering are a strong function of the diameter of the particulate and also of the electron beam energy. Finally, a new
method to determine the thickness of a thin film deposited on a substrate is proposed that does not require the measurement
of the beam current. That technique can also be used for a spherical particulate deposited on a substrate. 相似文献
5.
Jürgen Vogt Rolf-Horst Flagmeyer Johannes Heitmann Dietmar Lehmann Tilo Reinert Steffen Jankuhn Daniel Spemann Wolfgang Tröger Tilman Butz 《Mikrochimica acta》2000,133(1-4):105-111
The high-energy ion nanoprobe LIPSION at the University of Leipzig has been operational since October 1998. The ultrastable
single ended 3.5 MV SINLETRONTM accelerator supplies the H+ or He+ ion beam. A magnetic scanning system moves the focused beam across the sample. At present, a resolution of 150 nm in the
low current mode and 300 nm at 5 pA could be achieved.
The UHV grade experimental chamber is equipped with electron-, energy dispersive X-ray-, and particle detectors. They can
be used simultaneously to analyse the sample by means of PIXE (particle induced X-ray emission), RBS (Rutherford backscattering)
and in the case of thin samples STIM (scanning transmission ion microscopy).
A goniometer allows the application of channeling measurements in single crystals in combination with these methods.
The detection limits depend on the elements to be analysed and range from (1000⋯1) μg/g relative and (1⋯0.01) pg absolute.
The analysis is nondestructive, but the sample has to be vacuum resistant. Applications of the nanoprobe in the field of semiconductor
research, biomedicine, and archaeology will be described. 相似文献
6.
John F. Mansfield 《Mikrochimica acta》2000,132(2-4):137-143
In this paper, the application of X-ray energy dispersive spectroscopy in the environmental scanning electron microscope
is reviewed. Various techniques that have been used to remove the effects of the beam spreading in the gaseous environment
are discussed, specifically the pressure variation techniques and the beam-stop method. The results of the application of
modified versions, developed at the University of Michigan, are also presented. It is shown that quantitative analysis in
the environmental SEM, operating at 30 kV, is possible at short working distances (6 mm to 7.2 mm, gas path length 1.2 mm
to 2.2 mm) in the 70 to 350 Pa range. 相似文献
7.
Jens Höhne Matthias Bühler Roger von Hentig Theo Hertrich Uwe Hess Kevin Phelan Doreen Wernicke Derek Redfern Joseph Nicolosi 《Mikrochimica acta》2002,138(3-4):259-264
High resolution, superconducting detectors allow energy dispersive X-ray spectrometry (EDX) with energy resolution and energy
threshold far beyond the levels obtained with semiconductor detectors. These cryogenic detectors are run at temperatures of
less than 100 mK and combine the excellent energy resolution of wavelength dispersive X-ray spectrometry (WDX) with the fast,
energy dispersive analysis of EDX. CSP cryogenic spectrometer’s microcalorimeter type EDX cryodetectors are equipped with
a mechanical cooling system that runs vibration free and allows completely automated operations on scanning electron microscopes
(SEMs), field emission guns (FEGs) and transmission electron microscopes (TEMs). This detector type offers new opportunities
in material analysis, especially when low excitation energies are applied or light elements are to be determined. 相似文献
8.
Various K-, L- and M-shell X-ray production cross sections are measured for heavy ion impact on elements in the range Z
2 = 13 to 83. The ion species range from Z
1 = 10 to 36, and ion energies from 1 to 16 MeV are used. Enhanced cross sections are observed when the projectile K- or L-
binding energy is similar to the energy of the target K-, L- or M-shell. This effect is used to improve the analysis sensitivity
for selected elements. As an example trace analysis of Fe in glass with V, Mn, Co and Ni ions is investigated. Results are
compared with proton induced X-ray emission analysis on the same samples. In these samples Fe-Kα X-ray production is similar for irradiation with 3 MeV protons and 14 MeV Ni ions. However the signal to background ratio
is four times higher for the irradiation with Ni ions as compared to irradiation with protons. Advantages and drawbacks of
heavy ion induced X-ray emission for quantitative analysis compared to proton induced X-ray emission analysis are discussed. 相似文献
9.
Concentration profiles due to (inter)diffusion in materials may require high spatial resolution. These profiles may be measured
by electron probe microanalysis, which allows one to determine the elemental composition with a good accuracy provided measurement
‘artefacts’ can be accounted for. Standard phenomena are usually corrected by commercial softwares that assume a homogeneous
elemental composition in the analysed area. However, in the case of a diffusion process on a small scale, the composition
is no longer homogeneous and the effect of the hemispherical volume of the X-ray emission on the spatial resolution of the
concentration profiles, and consequently on the diffusion coefficients, has to be considered. Moreover, (secondary) fluorescence
across interfaces or interphases has to be evaluated. A radial X-ray distribution associated with the characteristic depth
distribution, φ(ρz), allows for the definition of a 2D X-ray emission function that enables the computation of the entire process for a given
concentration profile. 相似文献
10.
Ottinger F Kroslakova I Hametner K Reusser E Nesper R Günther D 《Analytical and bioanalytical chemistry》2005,383(3):489-499
Single crystals of new nitridosilicates and nitridoaluminosilicates with excellent R values in X-ray investigations were analysed quantitatively using 30 to 60 μm single-spot LA-ICP-MS. Significant discrepancies
between expected and measured chemical composition could not be explained by the crystallographic data. High spatial resolution
analysis using electron probe microanalysis (EPMA, 10 μm) leads to the discovery of inhomogeneities in the crystalline material.
The application of standard single-spot LA-ICP-MS with a spatial resolution of 30 to 60 μm is not suitable for the analysis
of these crystals as the existing inhomogeneities dominate and alter the determined concentrations. However, owing to the
better detection capabilities, a scanning LA-ICP-MS procedure enables a more representative analysis of single crystals of
Ca5Si2Al2N8 than single-spot LA-ICP-MS as a result of a larger sampling volume. It is highly likely that these impurities consist of
amorphous, vitreous phases as powder diffraction X-ray data indicates the existence of a significant fraction of an X-ray
amorphous material besides crystalline silicates. These microdomains contain less aluminium, silicon and calcium or are nearly
free of aluminium, which explains the detected discrepancies in the chemical composition. 相似文献
11.
Dubravka Jembrih Manfred Schreiner Momtchil Peev Peter Krejsa Christian Clausen 《Mikrochimica acta》2000,133(1-4):151-157
Art Nouveau (Tiffany, Loetz) and modern (Jack Ink, Strini Art Glass) iridescent glass fragments were characterized using
energy dispersive X-ray fluorescence analysis (EDXRF) and energy dispersive X-ray microanalysis in a scanning electron microscope
(SEM/EDX) in combination with factor analysis in order to obtain clustring. A character istic of Tiffany glass fragments is
leaded bulk glass, whereas in the case of Loetz K-Ca-Si bulk glass could be determined. Modern glass fragments show a high
amount of Na (7 wt% in the bulk of Jack Ink) and 0.6–1.5 wt% Sr in the bulk of Strini Art Glass. The contents of Si and Ca
are similar to Loetz glass. Furthermore, the differences in the structure of the glass artifacts could be determined. The
cross-sections of Tiffany show a layered structure of the bulk without a specific surface layer whereas the cross-sections
of Loetz glass reveal a homogeneous bulk material with one or two homogeneous surface layers in the BE-image. In the case
of the Jack Ink a homogeneous bulk glass and an inhomogeneous multilayered surface could be determined. Strini Art Glass show
a homogeneous bulk glass and a homogeneous surface layer in the backscattered electron image. 相似文献
12.
There are particular benefits in spectrum simulation for the interpretation of characteristic X-ray peaks below about 2 keV
in energy, where peak overlaps, a sloping background and changing detector efficiency make it difficult to measure true peak
intensities. Despite these difficulties, we have shown that a useful accuracy of simulation is possible without major revision
of the existing theory, allowing the electron microprobe user to compare on-line a measured spectrum with one synthesised
from an assumed sample composition.
As part of a wider study, we have used a database of X-ray spectra from 150 samples of known composition to confirm the accuracy
of simulation over the energy range from 0.28–1.9 keV, finding an RMS error of better than 8%. The database included 181 Kα,
Lα and Mα peaks from elements of atomic number 6–77, excited by beam voltages from 5–30 kV. Central to the method is the use
of the ratio of (Peak Intensity)/(Total Background Intensity), which allows spectra to be compared from instruments of differing
collection efficiency, thereby easing the collection of data over a wide range of conditions.
Examples are given to illustrate the use of the simulator in helping to choose the best conditions for analysis, and as an
aid in interpreting the spectra so obtained. Both modes of operation are iterative in nature and require a fast and accurate
simulator that is easy to use. Further development will be guided by experience in its use. 相似文献
13.
Binary and ternary potassium, rubidium and caesium glasses were irradiated by an electron beam with energy varying from 10
to 50 keV. Alkali ion X-ray decays were recorded and afterward incubation periods were determined. The incubation period versus
electron energy curves revealed thresholds, which are typical for each alkali species. The threshold ratios are proportional
to the mass of the alkali species, consistent with the suggested elastic scattering assisted hopping mechanism. 相似文献
14.
Jelica Novakovic Olga Papadopoulou Panayota Vassiliou Eleni Filippaki Yannis Bassiakos 《Analytical and bioanalytical chemistry》2009,395(7):2235-2244
Reference Cu-based alloy with chemical composition and micro-chemical structure similar to that of ancient alloys has been
used for carrying out the artificial long-term degradation test based on chloride enriched soil (chemical + soil) degradation.
The results show that such degradation procedure produces natural like “patinas” as the ones grown on archaeological artefacts,
from a chemical, structural and micro-morphological point of view. Glow discharge plasma technique has been employed for the
treatment of the as-corroded bronze coupons. The gradual elimination of chloride-containing corrosion products in favour of
the formation of more stable species and even the complete reduction back to copper has been observed. The chemical and metallurgical
features have been determined by combined use of different analytical techniques such as scanning electron microscopy with
energy dispersive X-ray micro-analysis (SEM-EDS), X-ray diffraction (XRD) and optical microscopy. 相似文献
15.
Norbert Lesch Anke Aretz Markus Pidun Silvia Richter Peter Karduck 《Mikrochimica acta》2000,132(2-4):377-382
A common problem in depth profile measurement is the calibration of the depth scale. The new technique of sputter assisted
electron probe microanalysis offers the possibility of calculating the composition as well as the depth scale solely from
the acquired X-ray intensity data without further information, e.g. sputter rates. To achieve a depth resolution that is smaller
than the depth of information of the electron probe, i.e. 0.1–1 μm, special deconvolution algorithms must be applied to the
acquired data.
To assess the capabilities of this new technique it was applied to a Ti/Al/Ti multilayer on Si under different measurement
conditions. Quantitative depth profiles were obtained by application of a deconvolution algorithm based on maximum entropy
analysis. By comparison of these profiles with AES depth profiles and AFM roughness measurements, it was shown that the limiting
factor to the achievable depth resolution is the occurrence of surface roughening induced by the sputtering process rather
than the relatively large depth of information of the electron probe.
We conclude that for certain applications sputter-assisted EPMA can be regarded as a valid depth profiling technique with
a depth resolution in the nm range. 相似文献
16.
Soft X-ray spectromicroscopy on solid-stabilized emulsions 总被引:2,自引:0,他引:2
Oil–water emulsions stabilized by solids have been imaged with sub-100 nm spatial resolution and analyzed spectroscopically
using a scanning transmission X-ray microscope. The emulsions are stabilized by particle heterocoagulate cages surrounding
the oil droplets. These cages form due to the interaction of negatively charged clay mineral particles (sodium montmorillonite,
Wyoming) and positively charged particles of calcium/aluminum layered double hydroxide (LDH). The emulsions were studied at
atmospheric pressure, without any pretreatment using carbon K and calcium L X-ray absorption edges. Oil- and calcium-rich LDH were separately mapped, and the clay mineral dispersions were also imaged.
Applying X-ray absorption-edge contrast, oil could be distinguished from water in the emulsion near the carbon K absorption edge (284 eV, 4.4 nm). Spectromicroscopy near the calcium L absorption edge (346 eV, 3.6 nm) allowed the structural details of heterocoagulate formation to be revealed.
Received: 11 December 1998 Accepted in revised form: 10 January 1999 相似文献
17.
Mass spectrometry (MS) imaging is a versatile method to analyze the spatial distribution of analytes in tissue sections. It
provides unique features for the analysis of drug compounds in pharmacokinetic studies such as label-free detection and differentiation
of compounds and metabolites. We have recently introduced a MS imaging method that combines high mass resolution and high
spatial resolution in a single experiment, hence termed HR2 MS imaging. In the present study, we applied this method to analyze the spatial distribution of the anti-cancer drugs imatinib
and ifosfamide in individual mouse organs. The whole kidney of an animal dosed with imatinib was measured at 35 μm spatial
resolution. Imatinib showed a well-defined distribution in the outer stripe of the outer medulla. This area was analyzed in
more detail at 10 μm step size, which constitutes a tenfold increase in effective spatial resolution compared to previous
studies of drug compounds. In parallel, ion images of phospholipids and heme were used to characterize the histological features
of the tissue section and showed excellent agreement with histological staining of the kidney after MS imaging. Ifosfamide
was analyzed in mouse kidney at 20 μm step size and was found to be accumulated in the inner medulla region. The identity
of imatinib and ifosfamide was confirmed by on-tissue MS/MS measurements. All measurements including mass spectra from 10
μm pixels featured accurate mass (≤2 ppm root mean square) and mass resolving power of R = 30,000. Selected ion images were generated with a bin size of ∆m/z = 0.01 ensuring highly specific information. The ability of the method to cover larger areas was demonstrated by imaging
a compound in the intestinal tract of a rat whole-body tissue section at 200 μm step size. The described method represents
a major improvement in terms of spatial resolution and specificity for the analysis of drug compounds in tissue sections. 相似文献
18.
Quantitative electron-probe microanalysis was used to determine the chemical composition of an Fe- and Nb-doped bismuth-based
BaBi4Ti4O15 perovskite compound. Elemental concentrations of Fe, Nb, Bi, Ba and Ti were accurately measured using wavelength-dispersive
X-ray spectroscopy that was optimised for the analysis of a complex oxide matrix containing minor concentrations of dopants.
Measurements were performed with a JEOL JXA 840A electron probe microanalyser at 20 and 26 kV, 50 nA beam current, 100 s maximum
counting time and 0.3% preset counting deviation (σc) using both PET and LiF crystals. K-ratios were quantified by the ZAF and the φ(ρz) PAP matrix-correction procedures. The
results showed that dopants incorporate into the BaBi4Ti4O15 at Ti4 + sites according to the Ba1−4XBi4 + 4XTi4−4XFe4XO15 and Ba1 + 4XBi4−4XTi4−4XNb4XO15 solid-solution formulae. The majority of the excess charge introduced by the substitution of Ti4 + with Fe3 + or Nb5 + is compensated for the change in the Ba2 + /Bi3 + ratio. 相似文献
19.
In order to obtain more accurate experimental values of X-ray emission cross sections, resulting from the interaction of
ion with atoms, we have measured them for the K-inner-shell of Cr and Cu elements using a proton beam of energy range 1–2.3 MeV.
The experimental data obtained in the present work are compared with the theoretical calculations given by the two models
BEA (binary encounter approximation) and ECPSSR (energy coulombian perturbed stationary state relativistic). Also, the present
experimental results are compared with those obtained by Paul and Sachert. The comparison shows a good agreement between the
previous and the present data with a slight improvement in the measurement accuracy for Cr. From the theoretical point of
view, agreement with the experimental data is observed only for the ECPSSR predictions, while the BEA’s cross section calculations
at higher energies are approximately 20% lower than the present experimental values. 相似文献
20.
With the implementation of focused primary ion beams, secondary ion mass spectrometry (SIMS) has become a significant technique
in the rapidly emerging field of mass spectral imaging in the biological sciences. Liquid metal ion guns (LMIG) offered the
prospect of sub-100 nm spatial resolution, however this aspiration has yet to be reached for molecular imaging. This brief
review shows that using LMIG the limitations of the static limit and low ionization probability will restrict useful imaging
to around 2 μm spatial resolution with high-yield molecules. The only prospect of going beyond this in the absence of factors
of 100 increase in ionization probability is to use polyatomic ion beams such as C60+, for which bombardment induced damage is low. In these cases sub-micron imaging becomes possible, using voxels together with
molecular depth profiling and 3D imaging. The discussion shows that conventional ToF-SIMS instrumentation then becomes a limitation
in that the pulsed ion beam has a very low duty cycle which results in inordinately long analysis times, and pulsing the beam
means that high-mass resolution and high spatial resolution are mutually incompatible. New instrumental configurations are
described that allow the use of a dc ion beam and separate the mass spectrometry for the ion formation process. Early results
from these instruments suggest that sub-micron analysis and imaging with high mass resolution and good ion yields are now
realizable, although the low ion yield issue still needs to be solved. 相似文献