Quantitative EELS mapping of biological thin sections

1992 ◽  
Vol 50 (2) ◽  
pp. 1568-1569
Author(s):  
Y.Y. Wang ◽  
Z. Shao ◽  
R. Ho ◽  
A.V. Somlyo ◽  
A.P. Somlyo
Keyword(s):  
Spatial Resolution ◽  
Power Law ◽  
High Spatial Resolution ◽  
Local Composition ◽  
Thin Sections ◽  
X Ray ◽  
Elemental Concentrations ◽  
Transmission Electron ◽  
High Concentrations ◽  
Electron Energy Loss

X-ray microanalysis and electron energy loss spectroscopy are reliable methods for determining at high spatial resolution the local composition of biological materials. EELS imaging, although potentially more sensitive than X-ray analysis, is complicated by the large background of EELS spectra. The conventional power law fitting of the EELS background can only be used for analysis of high concentrations and/or very thin sections (t< 0.3 λ) and it is not reliable for mapping low elemental concentrations. For the detection of low elemental concentrations at high spatial resolution, the background subtraction of the EELS spectrum and correction of long term microscope drift are critical, and limit the use of conventional energy filtered transmission electron microscopy. Therefore, we used energy filtered STEM with multiple least squares fitting, including the plural plasmon contribution to the background, to obtain quantitative phosphorus (P) and calcium (Ca) concentration maps of cryosections.The failure of the power law is due to the plural scattering contributions to the Background.

High Spatial Resolution Compositional Analysis at Interfaces

1980 ◽  
Vol 38 ◽  
pp. 356-359
Author(s):  
John B. Vander Sande ◽  
Thomas F. Kelly ◽  
Douglas Imeson
Keyword(s):  
Electron Microscope ◽  
High Spatial Resolution ◽  
Compositional Analysis ◽  
Scanning Transmission Electron Microscope ◽  
Thin Specimen ◽  
X Ray ◽  
Volume Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

In the scanning transmission electron microscope (STEM) a fine probe of electrons is scanned across the thin specimen, or the probe is stationarily placed on a volume of interest, and various products of the electron-specimen interaction are then collected and used for image formation or microanalysis. The microanalysis modes usually employed in STEM include, but are not restricted to, energy dispersive X-ray analysis, electron energy loss spectroscopy, and microdiffraction.

Experimental verification of the need for either jj or intermediate coupling in the 5f states of plutonium

2003 ◽  
Vol 802 ◽  
Author(s):  
K. T. Moore ◽  
M. A. Wall ◽  
A. J. Schwartz ◽  
B. W. Chung ◽  
J. G. Tobin ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Electron Microscope ◽  
Synchrotron Radiation ◽  
Single Phase ◽  
High Spatial Resolution ◽  
Intermediate Coupling ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Energy Loss ◽  
X Ray Absorption

ABSTRACTHere, we demonstrate the power of electron energy-loss spectroscopy (EELS) in a transmission electron microscope (TEM) to investigate the electronic structure plutonium. Using EELS, TEM, and synchrotron-radiation-based X-ray absorption spectroscopy (XAS), we provide the first experimental evidence that Russell-Saunders (LS) coupling fails for the 5f states of Pu. These results support the assumption that only the use of jj or intermediate coupling is appropriate for the 5f states of Pu. EELS experiments were performed in a TEM and are coupled with image and diffraction data, therefore, the measurements are completely phase specific. It is shown that EELS in a TEM may be used to circumvent the difficulty of producing single-phase or single-crystal samples due to its high spatial resolution.

Applications of high spatial resolution hicroanalysis to materials problems using dedicated STEM

1978 ◽  
Vol 36 (1) ◽  
pp. 418-419
Author(s):  
Ernest L. Hall ◽  
John B. Vander Sande
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Profile Analysis ◽  
Scanning Transmission Electron Microscope ◽  
Dramatic Improvement ◽  
X Ray ◽  
Transmission Electron ◽  
Probe Size ◽  
Scanning Transmission ◽  
Compositional Variations

The scanning transmission electron microscope has afforded a dramatic improvement in the spatial resolution of X-ray microanalysis of thin specimens, allowing the investigation of extremely localized compositional variations in materials systems. In this paper, the results of high resolution composition profile analysis in several materials are presented. The materials were analyzed in a 100 kV field emission STEM manufactured by VG Microscopes, Ltd., and fitted with an energy dispersive X-ray spectrometer. The specimens were held in a double-tilt graphite cartridge which allowed X-ray detection in the tilt range 0°-20° about each axis. The vacuum in the specimen chamber was ∿ 2 x 10-9 torr during analysis. Electron probe spot sizes of 5-10 Å were used, corresponding to probe currents in the range of 10-10-10-9 amps.For a given specimen composition, the spatial resolution of X-ray microanalysis in thin specimens is a function of probe size, accelerating voltage, specimen atomic number, and thickness.

High Spatial Resolution Microanalysis of Catalyst Particles

1985 ◽  
Vol 62 ◽  
Author(s):  
C. E. Lyman
Keyword(s):  
Image Feature ◽  
Single Element ◽  
X Rays ◽  
Qualitative And Quantitative Analysis ◽  
Thin Sections ◽  
X Ray ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
High Concentrations ◽  
Electron Energy Loss

ABSTRACTQualitative and quantitative analysis of small catalyst particles is possible in the analytical electron microscope down to analysis areas on the order of 10 nm in diameter. The location of elements in the image field can be determined either by placing the electron probe on a particu-lar image feature or by forming a digital x-ray image showing the distribu-tion of various elements. In either case analysis of specimens of well defined thickness such as microtomed thin sections preserves spatial relationships in catalyst particles and simplifies interpretation of single element x-ray images. Electron energy loss spectroscopy can be combined with x-ray spectroscopy to reduce the ambiguity in x-ray spectra caused by spurious x-rays generated by electrons scattered from the analy-sis area to regions of high concentrations of elements removed from the analysis area.

Parallel-EELS mapping of calcium in cryosectioned cells

1992 ◽  
Vol 50 (2) ◽  
pp. 1566-1567
Author(s):  
R.D. Leapman ◽  
J.A. Hunt ◽  
R.A. Buchanan ◽  
S.B. Andrews
Keyword(s):  
High Sensitivity ◽  
Scanning Transmission Electron Microscope ◽  
Mineralized Tissue ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Spectrum Imaging ◽  
High Concentrations ◽  
Electron Energy Loss ◽  
Better Than

Electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) provides a high sensitivity for microanalysis of certain important biological elements whose physiological concentrations in cells are rather low. Minimum detectable concentrations for calcium obtained by EELS can be better than those obtained by energy-dispersive x-ray spectroscopy (EDXS). However, in order to detect the very small core-edge signal/background ratios encountered in EELS of biological specimens, relatively elaborate acquisition and processing methods must be employed. Application of another strategy, STEM-EELS elemental mapping, has generally been restricted to analyses where elements are present at relatively high concentrations, such as calcium in mineralized tissue or carbon, nitrogen and oxygen in organic specimens.This is because only simple methods were available for signal estimation if the data had to be processed on-the-fly. Recently there has been considerable interest in the spectrum-imaging technique where entire spectra are collected at each pixel. In the present work we have applied this technique to measure calcium in Purkinje cell dendrites of rapidly frozen mouse cerebellar cortex.

Correlative electron and X-ray microscopy: probing chemistry and bonding with high spatial resolution

Nanoscale ◽  
2015 ◽  
Vol 7 (5) ◽  
pp. 1534-1548 ◽  
Author(s):  
Angela E. Goode ◽  
Alexandra E. Porter ◽  
Mary P. Ryan ◽  
David W. McComb
Keyword(s):  
Electron Microscope ◽  
Energy Loss ◽  
Transmission Electron Microscope ◽  
High Spatial Resolution ◽  
Scanning Transmission Electron Microscope ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss ◽  
X Ray Absorption

Benefits and challenges of correlative spectroscopy: electron energy-loss spectroscopy in the scanning transmission electron microscope (STEM-EELS) and X-ray absorption spectroscopy in the scanning transmission X-ray microscope (STXM-XAS).

High Spatial Resolution Assessment of the Structure, Composition, and Electronic Properties of Nanowire Arrays

2001 ◽  
Vol 635 ◽  
Author(s):  
M.S. Sander ◽  
A.L. Prieto ◽  
Y.M. Lin ◽  
R. Gronsky ◽  
A.M. Stacy ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electronic Properties ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Analytical Electron Microscopy ◽  
Nanowire Arrays ◽  
Composition Gradient ◽  
Transmission Electron ◽  
Analytical Electron ◽  
Electron Energy Loss

AbstractWe have employed transmission electron microscopy (TEM) and analytical electron microscopy to perform preliminary assessment of the structure, composition and electronic properties of nanowire arrays at high spatial resolution. The two systems studied were bismuth and bismuth telluride nanowire arrays in alumina (wire diameters ~40nm), both of which are promising for thermoelectric applications. Imaging coupled with diffraction in the TEM was employed to determine the grain size in electrodeposited Bi2Te3 nanowires. In addition, a composition gradient was identified along the wires in a short region near the electrode by energy-dispersive x-ray spectroscopy. Electron energy loss spectroscopy combined with energy-filtered imaging in the TEM revealed the excitation energy and spatial variation of plasmons in bismuth nanowire arrays.

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