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.

Eels Imaging of Biological Materials

1994 ◽  
Vol 332 ◽  
Author(s):  
R.D. Leapman ◽  
S. Sun ◽  
J.A. Hunt ◽  
S.B. Andrews
Keyword(s):  
Imaging Technique ◽  
Image Data ◽  
Scanning Transmission Electron Microscope ◽  
X Ray ◽  
Improvement Factor ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Spectrum Imaging ◽  
Electron Energy Loss ◽  
Electron Excitations

ABSTRACTParallel-detection electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope provides a very sensitive means of detecting specific elements in biological systems. By analyzing EELS spectrum-image data recorded from rapidly-frozen and cryosectioned tissue it is possible to map quantitatively the distribution of the biologically important element, calcium, which is typically present at concentrations of only a few parts per million in cellular structures some tens of nanometers in diameter. A significant improvement (factor of four) in calcium detectability has been demonstrated for EELS compared with energy-dispersive x-ray spectroscopy. The spectrum-imaging technique has also been applied to map water distributions in hydrated biological specimens by utilizing the valence electron excitations.

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.

Optimization of Acquisition Parameters for Atomic-Column Electron Energy-Loss Spectrum Imaging in a JEM-2200FS Aberration-Corrected Scanning Transmission Electron Microscope

2008 ◽  
Vol 14 (S2) ◽  
pp. 1400-1401 ◽  
Author(s):  
M Watanabe ◽  
M Kanno ◽  
D Ackland ◽  
CJ Kiely ◽  
DB Williams
Keyword(s):  
Electron Microscope ◽  
New Mexico ◽  
Energy Loss ◽  
Scanning Transmission Electron Microscope ◽  
Atomic Column ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Spectrum Imaging ◽  
Electron Energy Loss ◽  
Aberration Corrected

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

Efforts to improve the quantification of EDX analyses, particularly for the light elements

1991 ◽  
Vol 49 ◽  
pp. 716-717
Author(s):  
G. L'Espérance
Keyword(s):  
Scanning Transmission Electron Microscope ◽  
Light Elements ◽  
Thin Specimen ◽  
Complementary Technique ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Edx Analyses ◽  
Electron Energy Loss ◽  
Detection And Quantification

The attachment of a Si(Li) energy dispersive X-ray (EDX) detector to a (scanning) transmission electron microscope ((S)TEM) is widely used to carry out quantitative determinations of elemental composition of a localized region of a thin specimen. Although the principles of the technique first proposed by Cliff and Lorimer have been established for some time, there are still a large number of sources of errors. In addition, EDX analyses have been generally restricted until recently to elements with an atomic number (Z) larger than that of sodium (Z > 10) so that electron energy loss spectroscopy (EELS) was the preferred technique for the detection of light elements in an AEM. The relatively recent advent of ultra-thin window (UTW) detectors has offered an alternative (and often complementary) technique to EELS for the analysis of light elements with additional difficulties in the detection and quantification. This paper presents some results of investigations made to improve the quantification of EDX data. Particular attention is given to the detection and quantification of data from light elements on a routine and reproducible basis.

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-resolution x-ray imaging of small copper-rich precipitates in steels

1988 ◽  
Vol 46 ◽  
pp. 528-529
Author(s):  
J. R. Michael ◽  
K. A. Taylor
Keyword(s):  
Electron Microscopy ◽  
Thermomechanical Processing ◽  
Atom Probe ◽  
Ferrite Matrix ◽  
Scanning Transmission Electron Microscope ◽  
Probe Field ◽  
X Ray ◽  
Subsequent Transformation ◽  
Transmission Electron ◽  
Scanning Transmission

Although copper is considered an incidental or trace element in many commercial steels, some grades contain up to 1-2 wt.% Cu for precipitation strengthening. Previous electron microscopy and atom-probe/field-ion microscopy (AP/FIM) studies indicate that the precipitation of copper from ferrite proceeds with the formation of Cu-rich bcc zones and the subsequent transformation of these zones to fcc copper particles. However, the similarity between the atomic scattering amplitudes for iron and copper and the small misfit between between Cu-rich particles and the ferrite matrix preclude the detection of small (<5 nm) Cu-rich particles by conventional transmission electron microscopy; such particles have been imaged directly only by FIM. Here results are presented whereby the Cu Kα x-ray signal was used in a dedicated scanning transmission electron microscope (STEM) to image small Cu-rich particles in a steel. The capability to detect these small particles is expected to be helpful in understanding the behavior of copper in steels during thermomechanical processing and heat treatment.

The effect of small additions of Cu on precipitation in Al-Mg-Si alloys

1990 ◽  
Vol 48 (2) ◽  
pp. 442-443
Author(s):  
M. Tamizifar ◽  
G. Cliff ◽  
R.W. Devenish ◽  
G.W. Lorimer
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Scanning Transmission Electron Microscope ◽  
Argon Atmosphere ◽  
Age Hardening ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Analytical Electron ◽  
Scanning Transmission

Small additions of copper, <1 wt%, have a pronounced effect on the ageing response of Al-Mg-Si alloys. The object of the present investigation was to study the effect of additions of copper up to 0.5 wt% on the ageing response of a series of Al-Mg-Si alloys and to use high resolution analytical electron microscopy to determine the composition of the age hardening precipitates.The composition of the alloys investigated is given in Table 1. The alloys were heat treated in an argon atmosphere for 30m, water quenched and immediately aged either at 180°C for 15 h or given a duplex treatment of 180°C for 15 h followed by 350°C for 2 h2. The double-ageing treatment was similar to that carried out by Dumolt et al. Analyses of the precipitation were carried out with a HB 501 Scanning Transmission Electron Microscope. X-ray peak integrals were converted into weight fractions using the ratio technique of Cliff and Lorimer.

Phase Transformation of Powdered Material by Using Metal Jet

2012 ◽  
Vol 706-709 ◽  
pp. 741-744 ◽  
Author(s):  
Akio Kira ◽  
Ryuichi Tomoshige ◽  
Kazuyuki Hokamoto ◽  
Masahiro Fujita
Keyword(s):  
Phase Transformation ◽  
Powdered Material ◽  
Scanning Transmission Electron Microscope ◽  
Ultrahigh Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Metal Jet ◽  
Very High

The various techniques of phase transformation of the material have been proposed by many researchers. We have developed several devices to generate the ultrahigh pressure by using high explosive. One of them uses metal jets. It is expected that the ultrahigh pressure occurs by the head-on collision between metal jets, because the velocity of the metal jet is very high. By mixing a powdered material with metal jets, the pressure of the material becomes high. The purpose of this study is to transform the phase of the powdered material by using this high pressure. The powders of the graphite and hBN were applied. The synthesis to the diamond and cBN was confirmed by X-ray diffraction (XRD). In this paper, the mechanism of the generation of the ultrahigh pressure is explained and the results of the observation of the powder by using scanning transmission electron microscope (STEM) are reported.

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