On Some Testing Specimens for High Resolution SEM

1974 ◽  
Vol 32 ◽  
pp. 556-557
Author(s):  
P. S. D. Lin
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Transmission Electron Microscope ◽  
Carbon Films ◽  
Resolving Power ◽  
Bright Spots ◽  
Transmission Electron ◽  
Thin Carbon ◽  
Scanning Transmission ◽  
Scanning Electron

In assessing the resolving power of a high resolution scanning electron microscope using field emission tip (Hitachi HFS-2), two types of specimens were found to be of value.Fig. 1a, 1b are two successive exposures of some bright spots found on some thin carbon films. These carbon films were originally prepared for work in a high resolution scanning transmission electron microscope. Spots similar in size and distribution have been detected on micrographs taken in that microscope (Fig. 2).

The High Resolution Scanning Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 316-317
Author(s):  
A. V. Crewe
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
High Vacuum ◽  
Scanning Transmission Electron Microscope ◽  
Ultra High Vacuum ◽  
Resolving Power ◽  
Imaging Characteristics ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Moment

The high resolution STEM is now a fact of life. I think that we have, in the last few years, demonstrated that this instrument is capable of the same resolving power as a CEM but is sufficiently different in its imaging characteristics to offer some real advantages.It seems possible to prove in a quite general way that only a field emission source can give adequate intensity for the highest resolution^ and at the moment this means operating at ultra high vacuum levels. Our experience, however, is that neither the source nor the vacuum are difficult to manage and indeed are simpler than many other systems and substantially trouble-free.

High-resolution backscattered electron images in the scanning electron microscope

1992 ◽  
Vol 50 (2) ◽  
pp. 1608-1609
Author(s):  
Oliver C. Wells ◽  
P.C. Cheng
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Transmission Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
Atomic Resolution ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Backscattered Electron ◽  
Scanning Electron

In this discussion the words “high resolution imaging” of a solid sample in the scanning electron microscope (SEM) mean that details can be resolved that are considerably smaller than the penetration depth of the incident electron beam (EB) into the specimen. “Atomic resolution” in either the transmission electron microscope (TEM) or scanning transmission electron microscope (STEM) means that columns of atoms are resolved.Image contrasts in the backscattered electron (BSE) image are strongly affected by the specimen tilt and by the position and energy sensitivity of the BSE detector. The expression “BSE image” generally implies that the specimen is normal to the beam and the detector is above it. This shows compositional variations in the specimen with a spatial resolution limited by the spreading of the EB during the initial stages of penetration. This is similar in basic principle to the Z-Contrast method in the STEM that shows atomic resolution from a thinned single crystal mounted in the magnetic field of the focusing lens.

To What Extent are Inelastically Scattered Electrons Useful in the Stem?

1973 ◽  
Vol 31 ◽  
pp. 286-287 ◽  
Author(s):  
H. Rose
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Electron Correlation ◽  
Quantum Noise ◽  
Collection Efficiency ◽  
Scanning Transmission Electron Microscope ◽  
Electron Cloud ◽  
Scanning Time ◽  
Transmission Electron ◽  
Scanning Transmission

The scanning transmission electron microscope offers the possibility of utilizing inelastically scattered electrons. Use of these electrons in addition to the elastically scattered electrons should reduce the scanning time (dose) Which is necessary to keep the quantum noise below a certain level. Hence it should lower the radiation damage. For high resolution, Where the collection efficiency of elastically scattered electrons is small, the use of Inelastically scattered electrons should become more and more favorable because they can all be detected by means of a spectrometer. Unfortunately, the Inelastic scattering Is a non-localized interaction due to the electron-electron correlation, occurring predominantly at the circumference of the atomic electron cloud.

Scanning Secondary Electron Microscopy of Myofibrils Using Transmission Techniques

1975 ◽  
Vol 33 ◽  
pp. 556-557
Author(s):  
M. K. Lamvik
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Carbon Films ◽  
Photographic Recording ◽  
Transmission Electron ◽  
Thin Carbon ◽  
The Common ◽  
Scanning Electron ◽  
Better Than ◽  
Cellular Organelles

When observing small objects such as cellular organelles by scanning electron microscopy, it is often valuable to use the techniques of transmission electron microscopy. The common practice of mounting and coating for SEM may not always be necessary. These possibilities are illustrated using vertebrate skeletal muscle myofibrils.Micrographs for this study were made using a Hitachi HFS-2 scanning electron microscope, with photographic recording usually done at 60 seconds per frame. The instrument was operated at 25 kV, with a specimen chamber vacuum usually better than 10-7 torr. Myofibrils were obtained from rabbit back muscle using the method of Zak et al. To show the component filaments of this contractile organelle, the myofibrils were partially disrupted by agitation in a relaxing medium. A brief centrifugation was done to clear the solution of most of the undisrupted myofibrils before a drop was placed on the grid. Standard 3 mm transmission electron microscope grids covered with thin carbon films were used in this study.

Unique Features of a High Resolution Scanning Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 404-405
Author(s):  
J. W. Wiggins ◽  
M. Beer ◽  
D. C. Woodruff ◽  
J. A. Zubin
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
Heavy Atom ◽  
Scanning Transmission Electron Microscope ◽  
Objective Lens ◽  
Optical Parameters ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

A high resolution scanning transmission electron microscope has been constructed and is operating. The initial task of this instrument is to attempt the sequencing of DNA by heavy-atom specific staining. It is also suitable for many other biological investigations requiring high resolution, low contamination and minimum radiation damage.The basic optical parameters are: 20 to 100 KV acceleration potential, objective lens focal length of 1.0 mm. with Cs = 0.7 mm., and two additional lenses designated as condensor and diffraction lenses. The purpose of the condensor lens is to provide a parallel beam incident to the objective, and the diffraction lens produces an image of the back focal plane of the objective in the plane of an annular detector.

A High Resolution Dual Gun Electron Miscroscope for TEM and SEM

1974 ◽  
Vol 32 ◽  
pp. 422-423
Author(s):  
P. S. Ong ◽  
C. L. Gold
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Spot Size ◽  
Resolving Power ◽  
Objective Lens ◽  
Scanning System ◽  
Transmission Electron ◽  
Mode Of Operation ◽  
Electron Microscopes ◽  
Scanning Electron

Transmission electron microscopes (TEM) have the capability of producing an electron spot (probe) with a diameter equal to its resolving power. Inclusion of the required scanning system and the appropriate detectors would therefore easily convert such an instrument into a high resolution scanning electron microscope (SEM). Such an instrument becomes increasingly useful in the transmission mode of operation since it allows the use of samples which are considered too thick for conventional TEM. SEM accessories now available are all based on the use of the prefield of the objective lens to focus the beam. The lens is operated either as a symmetrical Ruska lens or its asymmetrical version. In these approaches, the condensor system of the microscope forms part of the reducing optics and the final spot size is usually larger than 20Å.

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