Migrating to digital imaging from film

1996 ◽  
Vol 54 ◽  
pp. 608-609
Author(s):  
J. R. Minter ◽  
K. Schlafer ◽  
G. Sotak ◽  
L. Thom
Keyword(s):  
New Technologies ◽  
Photographic Film ◽  
Digital Cameras ◽  
Image Size ◽  
Image Recording ◽  
Input Noise ◽  
Transmission Electron ◽  
Quantitative Image ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

Since the invention of the microscope, most images were recorded on photographic film. For transmission electron images, Hamilton and Marchant recognized that most photographic films are “nearly perfect detectors, in that they record the input signal without appreciable loss and do not seriously add to the input noise”. Despite film's efficiency as an image recorder, microscopists complained about the long cycle time between image recording and completion of the final print. Quantitative image analysis of images recorded on film is also time-consuming and expensive because microdensitometers capable of producing high quality and high resolution scans of negatives are slow and expensive.Over the past few years several new technologies to record light and electron images have been commercialized. The oldest of these are video-rate cameras and TV-rate cameras built with charge coupled devices (CCDs). These are limited by small image size (512 × 478). Larger format digital cameras built using slow-scan CCD cameras have recently been applied to light and transmission electron microscopy. Digital scan generators and frame buffers have been added to scanning electron microscopes.

The Observation of NBC Precipitates In Steels In The Nanometer Range Using A Field Emission Gun Scanning Electron Microscope

1997 ◽  
Vol 3 (S2) ◽  
pp. 1243-1244 ◽  
Author(s):  
Raynald Gauvin ◽  
Steve Yue
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Incident Electron Energy ◽  
Beam Diameter ◽  
Probe Diameter ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

The observation of microstructural features smaller than 300 nm is generally performed using Transmission Electron Microscopy (TEM) because conventional Scanning Electron Microscopes (SEM) do not have the resolution to image such small phases. Since the early 1990’s, a new generation of microscopes is now available on the market. These are the Field Emission Gun Scanning Electron Microscope with a virtual secondary electron detector. The field emission gun gives a higher brightness than those obtained using conventional electron filaments allowing enough electrons to be collected to operate the microscope with incident electron energy, E0, below 5 keV with probe diameter smaller than 5 nm. At 1 keV, the electron range is 60 nm in aluminum and 10 nm in iron (computed using the CASINO program). Since the electron beam diameter is smaller than 5 nm at 1 keV, the resolution of these microscopes becomes closer to that of TEM.

The Morphology of Obliterative Arterial Diseases in Statu Nascendi

1979 ◽  
Author(s):  
M. Marshall ◽  
J. Staubesand ◽  
H. Hese
Keyword(s):  
Risk Factors ◽  
Electron Microscope ◽  
Blood Platelet ◽  
Arterial Disease ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Mini Pigs ◽  
Scanning Electron ◽  
Blood Platelet Aggregation

The arteries of mini pigs which had been exposed to the local or systemic action of recognised ‘risk factors’ for arterial disease were examined with the light microscope, and the transmission and scanning electron microscopes. Initially the scanning instrument revealed adhesions of platelets in different stages of development, but showed an apparently intact endothelium. With the transmission electron microscope, however, degenerative changes in the endothelium could be observed. Increased blood platelet aggregation was also present. After a few weeks we could see a remarkable focal thickening of the intima, together with deposits on the endothelium of platelets, erythrocytes and fibrin (“mixed microparietal thrombosis”). After 6 months fully developed arteriosclerosis of the abdominal aorta had appeared.

scholarly journals Precession Electron Diffraction Assisted Orientation Mapping in the Transmission Electron Microscope

2010 ◽  
Vol 644 ◽  
pp. 1-7 ◽  
Author(s):  
Joaquim Portillo ◽  
Edgar F. Rauch ◽  
Stavros Nicolopoulos ◽  
Mauro Gemmi ◽  
Daniel Bultreys
Keyword(s):  
Electron Diffraction ◽  
X Ray Diffraction ◽  
Promising Technique ◽  
Electron Backscattered Diffraction ◽  
Transmission Electron ◽  
Orientation Mapping ◽  
Precession Electron Diffraction ◽  
Electron Microscopes ◽  
Ebsd Technique ◽  
Scanning Electron Microscopes

Precession electron diffraction (PED) is a new promising technique for electron diffraction pattern collection under quasi-kinematical conditions (as in X-ray Diffraction), which enables “ab-initio” solving of crystalline structures of nanocrystals. The PED technique may be used in TEM instruments of voltages 100 to 400 kV and is an effective upgrade of the TEM instrument to a true electron diffractometer. The PED technique, when combined with fast electron diffraction acquisition and pattern matching software techniques, may also be used for the high magnification ultra-fast mapping of variable crystal orientations and phases, similarly to what is achieved with the Electron Backscattered Diffraction (EBSD) technique in Scanning Electron Microscopes (SEM) at lower magnifications and longer acquisition times.

Three Dimensional Mask Metrology by Off-Axis Electron Holography

2001 ◽  
Vol 7 (S2) ◽  
pp. 574-575
Author(s):  
Bernhard Frost ◽  
David C Joy
Keyword(s):  
Three Dimensional ◽  
Ccd Camera ◽  
Electron Holography ◽  
Dimensional Metrology ◽  
Transmission Electron ◽  
Stereo Photogrammetry ◽  
Real Objects ◽  
Electron Microscopes ◽  
Third Dimension ◽  
Scanning Electron Microscopes

Even though all real objects are three dimensional, imaging and metrology performed by using electron-beam tools such as scanning electron microscopes is inherently two dimensional. Any information about the third dimension must therefore be obtained by inference, or by time consuming special methods such as stereo-photogrammetry. If, however, the structures of interest are thin enough to be electron transparent then quantitative three dimensional metrology can be performed directly by using off-axis transmission electron holography. Here we demonstrate the application to a SCALPEL lithography mask which consists of chromium lines on a silicon support film. The off-axis holography was performed in a field emission transmission electron microscope, a Hitachi HF2000 operated at 200keV. The sample is positioned so that half the beam passes through the specimen while the rest travels only through the vacuum. An electrostatic biprism then recombines these two components to form the hologram which is recorded onto a CCD camera.

Whither Scanning Electron Microscopy

1969 ◽  
Vol 27 ◽  
pp. 4-5
Author(s):  
T. E. Everhart
Keyword(s):  
Three Dimensional ◽  
Great Depth ◽  
Depth Of Field ◽  
Minimal Sample ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Dimensional Object ◽  
Scanning Electron Microscopes ◽  
Short Time ◽  
Scanning Electron

Although scanning electron microscopes have been available commercially for a relatively short time, their use is increasing rapidly. Countless persons have marvelled at their great depth of field, which produces an easily interpreted image of a three-dimensional object. Trained electron-microscopists have been impressed by the minimal sample preparation required for scanning microscope observation of inorganic objects, and of some organic objects. Non-specialists find the instrument easy to use, because many of the controls are related to familiar controls on television sets, on cathode-ray oscilloscopes, etc., and because the image on the cathode-ray tube screen is easy to interpret. Now seems the opportune moment to re-emphasize how the scanning electron microscope (SEM) differs fundamentally from the transmission electron (TEM), in order to insure that constraints imposed by the physics of image formation in the TEM will not be taken subconsciously as constraints in the SEM too.

Divergent-beam holography with a 200keV FE TEM

1991 ◽  
Vol 49 ◽  
pp. 678-679
Author(s):  
Xiao Zhang ◽  
David Joy
Keyword(s):  
Optical System ◽  
Photographic Film ◽  
Objective Lens ◽  
Electron Wave ◽  
Transmission Electron ◽  
High Resolution Images ◽  
Phase Data ◽  
Electron Microscopes ◽  
Complete Amplitude ◽  
Commercial Field

A hologram, first described and named by Gabor (1949), permits a medium such as photographic film, which responds only to intensity, to store the complete amplitude and phase information which characterizes an electron wavefront. The hologram is formed by allowing some fraction of a coherent electron wave which has interacted with a specimen to interact again with original incident wave so as to generate an interference pattern. If the hologram is then itself illuminated by a coherent light source and optical system which mimic the original electron-optical system then a pair of images -one real and the other virtual -can be reconstructed and viewed. Because the hologram contains both the amplitude and the phase data of the wavefront, errors and distortions in either component due to aberrations in the objective lens can be corrected by optical manipulates before the image is reconstructed. With the advent of commercial field emission transmission electron microscopes capable of generating both high resolution images and highly coherent electron beams, these holographic techniques are now available as practical tools to improve TEM performance as well as to create new modes of images (Tonomura 1987).

Advances in the EM of Polymers

1981 ◽  
Vol 39 ◽  
pp. 334-337
Author(s):  
L. C. Sawyer
Keyword(s):  
Optical Microscopy ◽  
Small Group ◽  
Fiber Morphology ◽  
The Past ◽  
Transmission Electron ◽  
Analytical Electron ◽  
Fine Structures ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

Recent advances in Analytical Electxon Microscopy (AEM) have changed the methods by which microicopists study polymer and fiber morphology. As polymeric materialis play a major role in our way of living - clothing, shelter, fuel, chemicals - the interest has spread from a small group of theoretical physicists to the larger group of applications scientists. Until forty years ago, optical microscopy (OM) provided the only microicopical means of observing the morphology of materials. Then transmission electron microscopes (TEM) brought a new depth and resolution of fine structures not previously known. The methodology of preparing materials for TEM, ultramicrotomy and replication, are revealing but tedious and replete with artifacts. Bridging the gap between OM and TEM the scanning electron microscopes (SEM), in use over the past fifteen years, have provided easily available and interpretable surface images of fibers, fabrics, membranes, films and composites. Finally, the limited resolution of the SEM has been improved by the use of modern composite instruments known as analytical electron microscopes (AEM).

Applications of In-situ Sample Preparation and Modeling of SEM-STEM Imaging

2008 ◽  
Author(s):  
R.J. Young ◽  
A. Buxbaum ◽  
B. Peterson ◽  
R. Schampers
Keyword(s):  
Sample Preparation ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Dual Beam ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Preparation Techniques

Abstract Scanning transmission electron microscopy with scanning electron microscopes (SEM-STEM) has become increasing used in both SEM and dual-beam focused ion beam (FIB)-SEM systems. This paper describes modeling undertaken to simulate the contrast seen in such images. Such modeling provides the ability to help understand and optimize imaging conditions and also support improved sample preparation techniques.

Electron Microscope Study of Strain in InGaN Quantum Wells in GaN Nanowires

2009 ◽  
Vol 1184 ◽  
Author(s):  
Roy Geiss ◽  
Kris Bertness ◽  
Alexana Roshko ◽  
David Read
Keyword(s):  
Electron Microscope ◽  
Quantum Wells ◽  
Cross Sections ◽  
Lattice Spacing ◽  
Gan Nanowires ◽  
Transmission Electron ◽  
Lattice Images ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Ingan Quantum Wells

AbstractStrains in GaN nanowires with InGaN quantum wells (QW) were measured from transmission electron microscope (TEM) images. The nanowires, all from a single growth run, are single crystals of the wurtzite structure that grow along the <0001> direction, and are approximately 1000 nm long and 60 nm to 130 nm wide with hexagonal cross-sections. The In concentration in the QWs ranges from 12 to 15 at %, as determined by energy dispersive spectroscopy in both the transmission and scanning electron microscopes. Fourier transform (FT) analyses of <0002> and <1100> lattice images of the QW region show a 4 to 10 % increase of the c-axis lattice spacing, across the full specimen width, and essentially no change in the a-axis value. The magnitude of the changes in the c-axis lattice spacing far exceeds values that would be expected by using a linear Vegard's law for GaN – InN with the measured In concentration. Therefore the increases are considered to represent tensile strains in the <0001> direction. Visual representations of the location and extent of the strained regions were produced by constructing inverse FT (IFT) images from selected regions in the FT covering the range of c-axis lattice parameters in and near the QW. The present strain values for InGaN QW in nanowires are larger than any found in the literature to date for other forms of InxGa1-xN (QW)/GaN.

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