In-Column Energy Filtering Transmission Electron Microscope (EFTEM) - Integrated Analysis of Energy Loss Signals

In an EFTEM the full range of signals generated by interaction of the primary electron beam with the specimen can be detected. Thus operating such a system and generating combined digital information usually is a rather complex issue. The demands of the users on the other hand are to achieve results fast, easily and reproducibly. Moreover it should be possible to tailor the integral system according to dedicated needs. In general it should be no problem to use modern digital equipment and just let an integral computer control everything. However, in order to make such digital settings really useful, there should be no D/A conversion in between the data paths of the microscope because any analogue system tends to drift and the changes of lens parameters between different modes of operation should be minimised to overcome hysteresis. Fully digitised in-column EFTEMs like the LEO EFTEMs with OMEGA filter and Koehler illumination including also multiple parallel and serial remote capabilities provide optimum preconditions to fulfil the demands.

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Electron Energy Loss Spectroscopy in the Electron Microscope: Present State of Affairs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070035 ◽

1978 ◽

Vol 36 (3) ◽

pp. 268-279

Author(s):

C. Colliex ◽

P. Trebbia

Keyword(s):

Electron Microscope ◽

Chemical Properties ◽

Primary Electron ◽

Formation Mechanisms ◽

Transmitted Beam ◽

Spatially Resolved ◽

Energy Filtering ◽

Transmission Electron ◽

Microanalytical Technique ◽

State Of Affairs

In the transmission electron microscope, among the various signals resulting from the interaction between the primary electron beam of well defined energy E0 and the specimen, the energy spectral distribution in the transmitted beam contains useful additional informations concerning the physical or chemical properties of the sample. As a consequence the insertion of a proper energy filtering device on any existing microscope column opens new fields of investigation from the fundamental understanding of the image formation mechanisms or the determination of the excitations spectrum in a solid to the development of a localized microanalytical technique at the spatially resolved scale of the electron microscope.

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Convergent-beam electron diffraction at high spatial resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130390 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1152-1153 ◽

Cited By ~ 1

Author(s):

J W Steeds

Keyword(s):

Electron Diffraction ◽

High Temperature Superconductors ◽

Bloch Wave ◽

Convergent Beam Electron Diffraction ◽

Beam Electron ◽

Energy Filtering ◽

Small Probe ◽

Transmission Electron ◽

Electron Microscopes ◽

Convergent Beam

That the techniques of convergent beam electron diffraction (CBED) are now widely practised is evident, both from the way in which they feature in the sale of new transmission electron microscopes (TEMs) and from the frequency with which the results appear in the literature: new phases of high temperature superconductors is a case in point. The arrival of a new generation of TEMs operating with coherent sources at 200-300kV opens up a number of new possibilities.First, there is the possibility of quantitative work of very high accuracy. The small probe will essentially eliminate thickness or orientation averaging and this, together with efficient energy filtering by a doubly-dispersive electron energy loss spectrometer, will yield results of unsurpassed quality. The Bloch wave formulation of electron diffraction has proved itself an effective and efficient method of interpreting the data. The treatment of absorption in these calculations has recently been improved with the result that <100> HOLZ polarity determinations can now be performed on III-V and II-VI semiconductors.

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The use of an energy-filtering electron microscope to reduce chromatic aberration in images of thick biological specimens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100142116 ◽

1986 ◽

Vol 44 ◽

pp. 88-91

Author(s):

L. D. Peachey ◽

J. P. Heath ◽

G. Lamprecht

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Electron Beam ◽

Cross Section ◽

Electron Scattering ◽

Chromatic Aberration ◽

Image Resolution ◽

Incident Electron Energy ◽

Energy Filtering ◽

Transmission Electron

Biological specimens of cells and tissues generally are considerably thicker than ideal for high resolution transmission electron microscopy. Actual image resolution achieved is limited by chromatic aberration in the image forming electron lenses combined with significant energy loss in the electron beam due to inelastic scattering in the specimen. Increased accelerating voltages (HVEM, IVEM) have been used to reduce the adverse effects of chromatic aberration by decreasing the electron scattering cross-section of the elements in the specimen and by increasing the incident electron energy.

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On-line image readout in CTEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100169730 ◽

1994 ◽

Vol 52 ◽

pp. 400-401

Author(s):

K.-H. Herrmann ◽

W. D. Rau ◽

R. Sikeler

Keyword(s):

Primary Electron ◽

Digital Information ◽

Electron Hole ◽

Detection Technology ◽

Long Time ◽

On Line ◽

Electron Image ◽

Optical Transfer ◽

Detection Quantum Efficiency ◽

Technical Solutions

Quantitative recording of electron patterns and their rapid conversion into digital information is an outstanding goal which the photoplate fails to solve satisfactorily. For a long time, LLL-TV cameras have been used for EM adjustment but due to their inferior pixel number they were never a real alternative to the photoplate. This situation has changed with the availability of scientific grade slow-scan charged coupled devices (CCD) with pixel numbers exceeding 106, photometric accuracy and, by Peltier cooling, both excellent storage and noise figures previously inaccessible in image detection technology. Again the electron image is converted into a photon image fed to the CCD by some light optical transfer link. Subsequently, some technical solutions are discussed using the detection quantum efficiency (DQE), resolution, pixel number and exposure range as figures of merit.A key quantity is the number of electron-hole pairs released in the CCD sensor by a single primary electron (PE) which can be estimated from the energy deposit ΔE in the scintillator,

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A computer-control program for TEM in situ fatigue experiments

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155074 ◽

1989 ◽

Vol 47 ◽

pp. 620-621

Author(s):

Kenneth S. Vecchio ◽

John A. Hunt

Keyword(s):

Slow Crack Growth ◽

Computer Control ◽

Control Program ◽

Video Tape ◽

Computer Control System ◽

Transmission Electron ◽

In Situ Experiments ◽

Tremendous Amount ◽

And Control

In-situ experiments conducted within a transmission electron microscope provide the operator a unique opportunity to directly observe microstructural phenomena, such as phase transformations and dislocation-precipitate interactions, “as they happen”. However, in-situ experiments usually require a tremendous amount of experimental preparation beforehand, as well as, during the actual experiment. In most cases the researcher must operate and control several pieces of equipment simultaneously. For example, in in-situ deformation experiments, the researcher may have to not only operate the TEM, but also control the straining holder and possibly some recording system such as a video tape machine. When it comes to in-situ fatigue deformation, the experiments became even more complicated with having to control numerous loading cycles while following the slow crack growth. In this paper we will describe a new method for conducting in-situ fatigue experiments using a camputer-controlled tensile straining holder.The tensile straining holder used with computer-control system was manufactured by Philips for the Philips 300 series microscopes. It was necessary to modify the specimen stage area of this holder to work in the Philips 400 series microscopes because the distance between the optic axis and holder airlock is different than in the Philips 300 series microscopes. However, the program and interfacing can easily be modified to work with any goniometer type straining holder which uses a penrmanent magnet motor.

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The new CM-Series TEMs: integration of a five-axis motorized, fully computer-controlled goniometer

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100147132 ◽

1993 ◽

Vol 51 ◽

pp. 258-259

Author(s):

Marc J.C. de Jong ◽

P. Emile S.J. Asselbergs ◽

Max T. Otten

Keyword(s):

Mechanical Design ◽

Computer Control ◽

Objective Lens ◽

Access Port ◽

Vibration Stability ◽

Transmission Electron ◽

Computer Controlled ◽

High Degree ◽

Five Axis ◽

Five Axes

A new step forward in Transmission Electron Microscopy has been made with the introduction of the CompuStage on the CM-series TEMs: CM120, CM200, CM200 FEG and CM300. This new goniometer has motorization on five axes (X, Y, Z, α, β), all under full computer control by a dedicated microprocessor that is in communication with the main CM processor. Positions on all five axes are read out directly - not via a system counting motor revolutions - thereby providing a high degree of accuracy. The CompuStage enters the octagonal block around the specimen through a single port, allowing the specimen stage to float freely in the vacuum between the objective-lens pole pieces, thereby improving vibration stability and freeing up one access port. Improvements in the mechanical design ensure higher stability with regard to vibration and drift. During stage movement the holder O-ring no longer slides, providing higher drift stability and positioning accuracy as well as better vacuum.

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