Seeing is Not Always Believing: Reduction of Artefacts by an Improved Point Resolution With a Spherical Aberration Corrected 200 Kv Transmission Electron Microscope

1997 ◽  
Vol 3 (S2) ◽  
pp. 1179-1180 ◽  
Author(s):  
M. Haider ◽  
S. Uhlemann
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Materials Science ◽  
Imaging System ◽  
Periodic Structures ◽  
Spherical Aberration ◽  
Spatial Frequencies ◽  
Transmission Electron ◽  
Set Up ◽  
Aberration Corrected

The most interesting structures in materials science are non-periodic areas where the crystalline structure is disturbed such as interfaces, defects or dislocations. These non-periodic structures can be hidden by artefacts, caused by aberrations, and therefore they can be easier analysed if an aberration free imaging system can be used. Therefore, in order to improve the point resolution and to obtain easier access to the hidden information, a spherical aberration corrected 200 kV TEM, following a proposal by Rose, was set up.Phase contrast in a transmission electron microscope (TEM) is obtained, as it was shown by Scherzer, due to the phase shifting power of the wave aberrations as there are: the defocus and the spherical aberration. The defocus can be optimised in terms of the well transferred bandwidth of spatial frequencies (Scherzer defocus) Δfsch = (Cs*λ.)1/2. The upper limit of the spatial frequency without a contrast reversal when choosing a Scherzer defocus is called the point resolution d ≈ 0.71 (Cs λ3)1/4.

First application of a spherical‐aberration corrected transmission electron microscope in materials science

2002 ◽  
Vol 51 (suppl 1) ◽  
pp. S51-S58 ◽  
Author(s):  
Bernd Kabius ◽  
Max Haider ◽  
Stefan Uhlemann ◽  
Eugen Schwan ◽  
Knut Urban ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Materials Science ◽  
Spherical Aberration ◽  
Transmission Electron ◽  
Aberration Corrected

A project for on-line remote control of a high-voltage TEM

1995 ◽  
Vol 53 ◽  
pp. 82-83 ◽  
Author(s):  
B. Parvin ◽  
D. Agarwal ◽  
D. Owen ◽  
M.A. O'Keefe ◽  
K.H. Westmacott ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
High Voltage ◽  
Materials Science ◽  
Imaging System ◽  
Remote Access ◽  
Video Signals ◽  
Transmission Electron ◽  
Control Computer ◽  
On Line

On-line microscopy commenced with demonstrations for biological and SEM applications. For materials science, a project has recently been established to provide users of the NCEM with remote online access to a 1.5MeV Kratos EM-1500 high-voltage transmission electron microscope via existing wide area networks. Within this project we are developing and implementing a set of tools, protocols, and interfaces to bring transmission electron microscopy on-line for collaborative research. Initially applied to the Kratos, the project will provide increased utilization of this unique instrument with its heretofore restricted access due to its sensitive components and demand for sophisticated operator skills. Additionally, the project will provide computer tools for capturing and manipulating real-time audio and video signals. These tools will be integrated into a standardized user interface that may be used for remote access to any transmission electron microscope equipped with a suitable control computer.Dynamic study of a specimen in an electron microscope requires continuous adjustment of specimen position and orientation under the beam, illumination conditions, focus adjustments, and corrections for aberrations, all based upon the video signal coming from the imaging system.

scholarly journals Sub-Ångstrom Low-Voltage Performance of a Monochromated, Aberration-Corrected Transmission Electron Microscope

2010 ◽  
Vol 16 (4) ◽  
pp. 386-392 ◽  
Author(s):  
David C. Bell ◽  
Christopher J. Russo ◽  
Gerd Benner
Keyword(s):  
Electron Microscope ◽  
Electron Energy ◽  
Transmission Electron Microscope ◽  
Cross Sections ◽  
Materials Science ◽  
Low Voltage ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Voltage Performance ◽  
Aberration Corrected

AbstractLowering the electron energy in the transmission electron microscope allows for a significant improvement in contrast of light elements and reduces knock-on damage for most materials. If low-voltage electron microscopes are defined as those with accelerating voltages below 100 kV, the introduction of aberration correctors and monochromators to the electron microscope column enables Ångstrom-level resolution, which was previously reserved for higher voltage instruments. Decreasing electron energy has three important advantages: (1) knock-on damage is lower, which is critically important for sensitive materials such as graphene and carbon nanotubes; (2) cross sections for electron-energy-loss spectroscopy increase, improving signal-to-noise for chemical analysis; (3) elastic scattering cross sections increase, improving contrast in high-resolution, zero-loss images. The results presented indicate that decreasing the acceleration voltage from 200 kV to 80 kV in a monochromated, aberration-corrected microscope enhances the contrast while retaining sub-Ångstrom resolution. These improvements in low-voltage performance are expected to produce many new results and enable a wealth of new experiments in materials science.

A spherical-aberration-corrected 200kV transmission electron microscope

1998 ◽  
Vol 75 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Max Haider ◽  
Harald Rose ◽  
Stephan Uhlemann ◽  
Eugen Schwan ◽  
Bernd Kabius ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Spherical Aberration ◽  
Transmission Electron ◽  
Aberration Corrected

scholarly journals Performance and Application of Chromatic/Spherical Aberration-Corrected 30 kV Transmission Electron Microscope

2011 ◽  
Vol 17 (S2) ◽  
pp. 1530-1531 ◽  
Author(s):  
T Sasaki ◽  
H Sawada ◽  
F Hosokawa ◽  
Y Shimizu ◽  
T Nakamichi ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Spherical Aberration ◽  
Transmission Electron ◽  
Aberration Corrected

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

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