High-resolution imaging on a field emission TEM

1993 ◽  
Vol 48 (1-2) ◽  
pp. 77-91 ◽  
Author(s):  
Max T. Otten ◽  
Wim M.J. Coene
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
High Resolution Imaging ◽  
Resolution Imaging

Principle and practice of high-resolution imaging with a field-emission TEM

1992 ◽  
Vol 50 (1) ◽  
pp. 138-139
Author(s):  
Max T. Otten ◽  
Wim M.J. Coene
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Incidence Angle ◽  
Temporal Coherence ◽  
Energy Spread ◽  
High Resolution Imaging ◽  
Major Improvement ◽  
High Resolution Images ◽  
Resolution Imaging

High-resolution imaging with a LaB6 instrument is limited by the spatial and temporal coherence, with little contrast remaining beyond the point resolution. A Field Emission Gun (FEG) reduces the incidence angle by a factor 5 to 10 and the energy spread by 2 to 3. Since the incidence angle is the dominant limitation for LaB6 the FEG provides a major improvement in contrast transfer, reducing the information limit to roughly one half of the point resolution. The strong improvement, predicted from high-resolution theory, can be seen readily in diffractograms (Fig. 1) and high-resolution images (Fig. 2). Even if the information in the image is limited deliberately to the point resolution by using an objective aperture, the improved contrast transfer close to the point resolution (Fig. 1) is already worthwhile.

High-resolution SE-I imaging of biological membranes using a Schottky field-emission in-lens SEM

1991 ◽  
Vol 49 ◽  
pp. 516-517
Author(s):  
R.P. Apkarian
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Emission Sources ◽  
High Resolution Imaging ◽  
Cold Cathode ◽  
Research Facility ◽  
Isolated Cells ◽  
Whole Cells ◽  
Resolution Imaging ◽  
Definition Of

Previous notes have described efforts to routinely collect quality SE-I image contrasts of biologically significant particulate membrane features (1-10 nm) in the context of whole cells and tissue fragments. Utilizing SEMs equipped with in-lens specimen stages and field emission sources (Schottky and cold cathode) operated at 15-30 kV and in conjunction with specimens coated with 1 nm Cr films (Z=24), nanometer resolution of biological samples may be attained. This note describes the definition of optimal electron source conditions for the high resolution imaging of cell membrane features μ 10 nm. The Schottky field emitter equipped ISI DS-130F SEM, in-house at the Yerkes Research Facility, was operated at 5-20 kV accelerating voltages (A.V.) and at 4 or 4.8 kV extraction voltages (E.V.). Although we have published images of soft and hard biological sections and isolated cells containing 1-10 nm particle contrasts by operating the SEM at 25-30 kV A.V., we have maintained 4 kV extraction voltage and not attempted using 4.8 kV above 25 kV A.V.

High Resolution CryoFESEM of Microbial Surfaces

2003 ◽  
Vol 9 (4) ◽  
pp. 273-278 ◽  
Author(s):  
Stanley Erlandsen ◽  
Ming Lei ◽  
Ines Martin-Lacave ◽  
Gary Dunny ◽  
Carol Wells
Keyword(s):  
High Resolution ◽  
Enterococcus Faecalis ◽  
Field Emission ◽  
Proteus Mirabilis ◽  
Giardia Lamblia ◽  
High Resolution Imaging ◽  
Backscatter Electron ◽  
Bacterial Flagella ◽  
Resolution Imaging ◽  
Double Coating

The outer surfaces of three microorganisms, Giardia lamblia, Enterococcus faecalis, and Proteus mirabilis, were investigated by cryo-immobilization followed by sublimation of extracellular ice and cryocoating with either Pt alone or Pt plus carbon. Cryocoated samples were examined at −125°C in either an in-lens field emission SEM or a below-the-lens field emission SEM. Cryocoating with Pt alone was sufficient for low magnification observation, but attempts to do high-resolution imaging resulted in radiolysis and cracking of the specimen surface. Double coating with Pt and carbon, in combination with high resolution backscatter electron detectors, enabled high-resolution imaging of the glycocalyx of bacteria, revealing a sponge-like network over the surface. High resolution examination of bacterial flagella also revealed a periodic substructure. Common artifacts included radiolysis leading to “cracking” of the surface, and insufficient deposition of Pt resulting in the absence of detectable surface topography.

A New 200kv Energy Filter Field Emission Transmission Electron Microscope

1998 ◽  
Vol 4 (S2) ◽  
pp. 396-397
Author(s):  
T. Kaneyama ◽  
K. Tsuno ◽  
T. Honda ◽  
M. Kersker ◽  
K. Tsuda ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Field Emission ◽  
Transmission Electron Microscope ◽  
High Resolution Imaging ◽  
Elemental Mapping ◽  
Lens System ◽  
Transmission Electron ◽  
Wide Range ◽  
Resolution Imaging

In the field of biological and materials sciences, the importance of energy filter transmission electron microscope(EF-TEM) is increasing. Because it is a powerful instrument for contrast enhancement and obtaining elemental mapping images. We have developed a 200kV EF-TEM equipped with a fieldemission gun and in-column spectrometer. The new EF-TEM JEM-2010FEF inherits the performance in high resolution imaging and analysis from field emission TEM. The outer view is shown in Fig.l.Figure 2 shows the lens configuration of JEM-2010FEF. An in-column Q-type spectrometer is introduced within the imaging lens system. It was designed to have image distortion less than 1% and dispersion power 1.2p.m/eV for 200keV electrons. There is no need of compensating procedure of distortion. Imaging lens system consists of two objective lenses, three intermediate lenses and three projector lenses. The 8-stage imaging lens system enables wide range of imaging modes equal to conventional TEMs; energy spectroscopic image of magnification from ×200 to × 1,500,000, energy spectroscopic diffraction of camera length from 200mm to 2,000mm.

Alternative approaches to ultra-high resolution imaging

1991 ◽  
Vol 49 ◽  
pp. 650-651
Author(s):  
J.M. Cowley
Keyword(s):  
High Resolution ◽  
High Voltage ◽  
High Resolution Electron Microscopy ◽  
Crystal Defects ◽  
High Resolution Imaging ◽  
General Applicability ◽  
Resolution Electron ◽  
Radiation Resistant ◽  
Resolution Imaging ◽  
Alternative Approaches

By extrapolation of past experience, it would seem that the future of ultra-high resolution electron microscopy rests with the advances of electron optical engineering that are improving the instrumental stability of high voltage microscopes to achieve the theoretical resolutions of 1Å or better at 1MeV or higher energies. While these high voltage instruments will undoubtedly produce valuable results on chosen specimens, their general applicability has been questioned on the basis of the excessive radiation damage effects which may significantly modify the detailed structures of crystal defects within even the most radiation resistant materials in a period of a few seconds. Other considerations such as those of cost and convenience of use add to the inducement to consider seriously the possibilities for alternative approaches to the achievement of comparable resolutions.

Performance and applications of a field-emission gun TEM/STEM

1992 ◽  
Vol 50 (2) ◽  
pp. 942-943
Author(s):  
Judith M. Brock ◽  
Max T. Otten ◽  
Marc. J.C. de Jong
Keyword(s):  
Field Emission ◽  
High Resolution Imaging ◽  
High Quality ◽  
Small Energy ◽  
High Brightness ◽  
Small Probe ◽  
Resolution Imaging ◽  
Convergent Beam ◽  
Beam Patterns ◽  
Beam Diffraction

A Field Emission Gun (FEG) on a TEM/STEM instrument provides a major improvement in performance relative to one equipped with a LaB6 emitter. The improvement is particularly notable for small-probe techniques: EDX and EELS microanalysis, convergent beam diffraction and scanning. The high brightness of the FEG (108 to 109 A/cm2srad), compared with that of LaB6 (∼106), makes it possible to achieve high probe currents (∼1 nA) in probes of about 1 nm, whilst the currents for similar probes with LaB6 are about 100 to 500x lower. Accordingly the small, high-intensity FEG probes make it possible, e.g., to analyse precipitates and monolayer amounts of segregation on grain boundaries in metals or ceramics (Fig. 1); obtain high-quality convergent beam patterns from heavily dislocated materials; reliably detect 1 nm immuno-gold labels in biological specimens; and perform EDX mapping at nm-scale resolution even in difficult specimens like biological tissue.The high brightness and small energy spread of the FEG also bring an advantage in high-resolution imaging by significantly improving both spatial and temporal coherence.

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