scholarly journals Automated Functions in Electron Microscopy

2004 ◽  
Vol 12 (6) ◽  
pp. 14-19
Author(s):  
Bill Tivol

The newest generation of computer-controlled electron microscopes incorporates the ability to perform adjustments to microscopy conditions by comparing pairs of images and altering the conditions accordingly. Automation of electron microscope adjustments offers the advantages of accuracy, precision, efficiency, the ability to incorporate the adjustments into other automated procedures, and, for radiation-sensitive specimens, minimal exposure to the beam.At present, automated functions include determination of eucentric height, focus, astigmatism, orientation and location of the stage tilt axis, centering of an image feature, and rotation center alignment. It is possible to automate other functions, so this list may be incomplete. In general, these functions are accomplished by induced image shifts, and, in many cases, the automated functions are completely analogous to the corresponding manual ones.

Author(s):  
M.A. O’Keefe ◽  
J. Taylor ◽  
D. Owen ◽  
B. Crowley ◽  
K.H. Westmacott ◽  
...  

Remote on-line electron microscopy is rapidly becoming more available as improvements continue to be developed in the software and hardware of interfaces and networks. Scanning electron microscopes have been driven remotely across both wide and local area networks. Initial implementations with transmission electron microscopes have targeted unique facilities like an advanced analytical electron microscope, a biological 3-D IVEM and a HVEM capable of in situ materials science applications. As implementations of on-line transmission electron microscopy become more widespread, it is essential that suitable standards be developed and followed. Two such standards have been proposed for a high-level protocol language for on-line access, and we have proposed a rational graphical user interface. The user interface we present here is based on experience gained with a full-function materials science application providing users of the National Center for Electron Microscopy with remote on-line access to a 1.5MeV Kratos EM-1500 in situ high-voltage transmission electron microscope via existing wide area networks. We have developed and implemented, and are continuing to refine, a set of tools, protocols, and interfaces to run the Kratos EM-1500 on-line for collaborative research. Computer tools for capturing and manipulating real-time video signals are integrated into a standardized user interface that may be used for remote access to any transmission electron microscope equipped with a suitable control computer.


2003 ◽  
Vol 67 (2) ◽  
pp. 219-231 ◽  
Author(s):  
H. W. Langmi ◽  
J. Watt

Computer-controlled scanning electron microscopy (CCSEM) has been assessed for the determination of form and size distribution of heavy metals in urban contaminated soils. Metal distributions within individual particles were determined using X-ray element mapping. The sites selected for study were (1) around a landfill site, previously a colliery in Wolverhampton, UK and (2) a private garden adjacent to a railway in Nottingham, UK. Backscattered thresholding techniques were used to isolate the Pb-containing categories. The classification results for both Wolverhampton and Nottingham soils were generally similar but more Pb-containing classes were observed for the Nottingham samples when a comparison was made between results of the same size fractions. However, difficulties with the technique arose when particles showing chemically similar weathering crusts were assigned to the same class, despite having different internal compositions. The CCSEM data therefore need to be interpreted with caution and their application limited to situations in which particle internal complexity is not an issue.


2013 ◽  
Vol 12 (4) ◽  
pp. 095-105
Author(s):  
Beata Klimek

One of the main tasks in the study of historic buildings is the need to identify the original materials and extensions, which often have historic character. The next task concerns the determination of the composition and structure of the historical, diagnosis technique to develop original paint. The article presents the preliminary results of paintings. Methods were used with the scanning electron microscope was equipped with an energy dispersive X-ray spectrometer (SEM-EDS).


2000 ◽  
Vol 6 (4) ◽  
pp. 380-387 ◽  
Author(s):  
Christopher John Edgcombe ◽  
Ugo Valdrè

AbstractAn overview and new results are presented of the investigations carried out in the last 5 years on nano-sized tips by means of electron microscopy, an electron optical bench, and computation. Tungsten and, in particular, carbon nano-tips prepared by carbon contamination in a scanning electron microscope, were studied for applications as field-emission electron sources. Several features of their use are described and the results concerning the determination of some of their basic properties are reported.


2020 ◽  
Vol 68 (6) ◽  
pp. 389-402
Author(s):  
Lars Möller ◽  
Gudrun Holland ◽  
Michael Laue

Diagnostic electron microscopy is a useful technique for the identification of viruses associated with human, animal, or plant diseases. The size of virus structures requires a high optical resolution (i.e., about 1 nm), which, for a long time, was only provided by transmission electron microscopes operated at 60 kV and above. During the last decade, low-voltage electron microscopy has been improved and potentially provides an alternative to the use of high-voltage electron microscopy for diagnostic electron microscopy of viruses. Therefore, we have compared the imaging capabilities of three low-voltage electron microscopes, a scanning electron microscope equipped with a scanning transmission detector and two low-voltage transmission electron microscopes, operated at 25 kV, with the imaging capabilities of a high-voltage transmission electron microscope using different viruses in samples prepared by negative staining and ultrathin sectioning. All of the microscopes provided sufficient optical resolution for a recognition of the viruses tested. In ultrathin sections, ultrastructural details of virus genesis could be revealed. Speed of imaging was fast enough to allow rapid screening of diagnostic samples at a reasonable throughput. In summary, the results suggest that low-voltage microscopes are a suitable alternative to high-voltage transmission electron microscopes for diagnostic electron microscopy of viruses.


2001 ◽  
Vol 7 (S2) ◽  
pp. 968-969
Author(s):  
Theo van der Krift ◽  
Ulrike Ziese ◽  
Willie Geerts ◽  
Bram Koster

The integration of computers and transmission electron microscopes (TEM) in combination with the availability of computer networks evolves in various fields of computer-controlled electron microscopy. Three layers can be discriminated: control of electron-optical elements in the column, automation of specific microscope operation procedures and display of user interfaces. The first layer of development concerns the computer-control of the optical elements of the transmission electron microscope (TEM). Most of the TEM manufacturers have transformed their optical instruments into computer-controlled image capturing devices. Nowadays, the required controls for the currents through lenses and coils of the optical column can be accessed by computer software. The second layer of development is aimed toward further automation of instrument operation. For specific microscope applications, dedicated automated microscope-control procedures are carried out. in this paper, we will discuss our ongoing efforts on this second level towards fully automated electron tomography. The third layer of development concerns virtual- or telemicroscopy. Most telemicroscopy applications duplicate the computer-screen (with accessory controls) at the microscope-site to a computer-screen at another site. This approach allows sharing of equipment, monitoring of instruments by supervisors, as well as collaboration between experts at remote locations.Electron tomography is a three-dimensional (3D) imaging method with transmission electron microscopy (TEM) that provides high-resolution 3D images of structural arrangements. with electron tomography a series of images is acquired of a sample that is tilted over a large angular range (±70°) with small angular tilt increments.


2003 ◽  
Vol 9 (2) ◽  
pp. 96-138 ◽  
Author(s):  
F. Haguenau ◽  
P.W. Hawkes ◽  
J.L. Hutchison ◽  
B. Satiat–Jeunemaître ◽  
G.T. Simon ◽  
...  

It is not easy to understand how the electron microscopes and electron microscope techniques that we know today developed from the primitive ideas of the first microscopists of the 1930s. Newcomers to the subject in particular, their time almost fully occupied with grasping practical methods and modern computing techniques, can rarely devote much attention to the history of their subject. For some, however, this is a source of frustration: If a guide to the principal stages in the development of the subject and to the main actors and their publications were available, they would find the time to study it.


2000 ◽  
Vol 6 (4) ◽  
pp. 380-387
Author(s):  
Christopher John Edgcombe ◽  
Ugo Valdrè

Abstract An overview and new results are presented of the investigations carried out in the last 5 years on nano-sized tips by means of electron microscopy, an electron optical bench, and computation. Tungsten and, in particular, carbon nano-tips prepared by carbon contamination in a scanning electron microscope, were studied for applications as field-emission electron sources. Several features of their use are described and the results concerning the determination of some of their basic properties are reported.


1997 ◽  
Vol 5 (1) ◽  
pp. 14-15
Author(s):  
Vivian Robinson

Ever since electron microscopes were developed, it has been the goal of microscopists to observe specimens in their natural state, free from artefacts which can often be introduced through specimen preparation. For most biological specimens, that includes the presence of water. With a pressure of 10-4 torr or lower required to operate a scanning electron microscope (SEM), liquid water, which required a pressure of above 5 torr, was clearly a problem.Although several attempts had been made to examine hydrated specimens in a SEM, the first published results of water imaged in a stable and reproducible manner in the SEM, were presented at the Eighth International Congress on Electron Microscopy in Canberra in 1974 (Robinson, 1974).


1961 ◽  
Vol 34 (2) ◽  
pp. 697-704 ◽  
Author(s):  
W. A. Ladd ◽  
M. W. Ladd

Abstract Until recently, the main role of the electron microscope in rubber research was the determination of particle size and shape of reinforcing pigments and fillers. The electron microscope proved its value in its first industrial problem in 1940 when it showed the particle size of Micronex to be 28 mµ. In 1942 it established the correlation between particle size of carbon and rubber properties. The next contribution was the establishment of reticulate chain structure, in 1945, using stereo-photomicrography. The electron microscope led the way to the carbon gel concept when carbons producing different road wear results were shown to have equal particle size and structure. Micrographs of carbon gel were published in 1951. Studies of rubber latexes, various pigments and fillers were also applications of the electron microscope in which the determination of particle size and shape was involved. Today, improvements in resolution, development of new techniques and accessory equipment have greatly expanded the application of the electron microscope. This paper is concerned mainly with describing these new developments ; first, as a help to electron microscopists in the rubber field; second, to illustrate what can be done with the electron microscope, so that research and production men can recognize possible applications of this discerning tool to the solution of their problems. Electron microscopes have come a long way in the short 20-year period. Figure 1 shows the microscope used in our laboratories. This instrument is currently resolving detail as fine as 10 A or 1 mµ in routine daily operation. Its design makes possible the development of special holders and thereby increases its value as a research tool. Another piece of equipment that is as important in microscope research as the electron microscope itself is the evaporating unit shown in Figure 2. This is used for shadowing and forming replication films under vacuum, thus making possible studies of rubber surfaces and surfaces of pigments and other rubber ingredients. In shadowing, detail is made visible by coating the specimen with metal evaporated at an angle from the tungsten basket at A. Carbon can be evaporated by the arc at B, forming a replicating film or mold of the specimen. This will be discussed under “preparation”. Today, the proper preparation of specimens is the most important step in successful microscopy. The various preparations used are as follows.


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