Electron Microscope Specimen Preparation Techniques in materials Science

1977 ◽  
pp. 1-136 ◽  
Author(s):  
K. C. Thompson-Russell ◽  
J. W. Edington
Keyword(s):  
Electron Microscope ◽  
Materials Science ◽  
Specimen Preparation ◽  
Preparation Techniques

The ionic strength dependence of chromatin folding

1978 ◽  
Vol 36 (2) ◽  
pp. 220-221
Author(s):  
F. Thoma ◽  
TH. Koller
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ionic Strength ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Carbon Supports ◽  
Ionic Strength Dependence ◽  
Chromatin Folding ◽  
Strength Dependence ◽  
Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

Comparison of freeze-fractured yeast replicas using conventional TEM and low-voltage field-emission SEM

1989 ◽  
Vol 47 ◽  
pp. 74-75
Author(s):  
William P. Wergin ◽  
Eric F. Erbe ◽  
Terrence W. Reilly
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Voltage ◽  
Objective Lens ◽  
Specimen Preparation ◽  
Lens System ◽  
Air Drying ◽  
Preparation Techniques ◽  
Scanning Electron

Although the first commercial scanning electron microscope (SEM) was introduced in 1965, the limited resolution and the lack of preparation techniques initially confined biological observations to relatively low magnification images showing anatomical surface features of samples that withstood the artifacts associated with air drying. As the design of instrumentation improved and the techniques for specimen preparation developed, the SEM allowed biologists to gain additional insights not only on the external features of samples but on the internal structure of tissues as well. By 1985, the resolution of the conventional SEM had reached 3 - 5 nm; however most biological samples still required a conductive coating of 20 - 30 nm that prevented investigators from approaching the level of information that was available with various TEM techniques. Recently, a new SEM design combined a condenser-objective lens system with a field emission electron source.

Analysis of Interesting Materials in the Environmental SEM: You Put What in Your Microscope?

2001 ◽  
Vol 7 (S2) ◽  
pp. 776-777
Author(s):  
John F. Mansfield
Keyword(s):  
Electron Microscope ◽  
Chemical Engineering ◽  
Materials Science ◽  
Variable Pressure ◽  
Environmental Scanning ◽  
Specimen Preparation ◽  
Wide Range ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

The environmental scanning electron microscope (ESEM™) and variable pressure electron microscope (VPSEM) have become accepted tools in the contemporary electron microscopy facility. Their flexibility and their ability to image almost any sample with little, and often no, specimen preparation has proved so attractive that each manufacturer of scanning electron microscopes now markets a low vacuum model.The University of Michigan Electron Microbeam Analysis Laboratory (EMAL) operates two variable pressure instruments, an ElectroScan E3 ESEM and a Hitachi S3200N VPSEM. The E3 ESEM was acquired in the early 1990s with funding from the Amoco Foundation and it has been used to examine an extremely wide variety of different materials. Since EMAL serves the entire university community, and offers support to neighboring institutions and local industry, the types of materials examined span a wide range. There are users from Materials Science & Engineering, Chemical Engineering, Nuclear Engineering, Electrical Engineering, Physics, Chemistry, Geology, Biology, Biophysics, Pharmacy and Pharmacology.

The Effect of Focused Ion Beam (Fib) Specimen Geometry on X-Ray Fluorescence During Energy Dispersive X-Ray Spectroscopy (EDS) Analysis in the Transmission Electron Microscope (TEM)

1998 ◽  
Vol 4 (S2) ◽  
pp. 856-857
Author(s):  
David M. Longo ◽  
James M. Howe ◽  
William C. Johnson
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Focused Ion Beam ◽  
Materials Science ◽  
Bulk Material ◽  
Ion Beam ◽  
Energy Dispersive ◽  
Specimen Preparation ◽  
X Ray ◽  
Transmission Electron

The focused ion beam (FIB) has become an indispensable tool for a variety of applications in materials science, including that of specimen preparation for the transmission electron microscope (TEM). Several FIB specimen preparation techniques have been developed, but some problems result when FIB specimens are analyzed in the TEM. One of these is X-ray fluorescence from bulk material surrounding the thin membrane in FIB-prepared samples. This paper reports on a new FIB specimen preparation method which was devised for the reduction of X-ray fluorescence during energy dispersive X-ray spectroscopy (EDS) in the TEM.Figure 1 shows three membrane geometries that were investigated in this study on a single-crystal Si substrate with a RF sputter-deposited 50 nm Ni film. Membrane 1 is the most commonly reported geometry in the literature, with an approximately 20 urn wide trench and a membrane having a single wedge with a 1.5° incline.

Microtomy applications for materials science

1989 ◽  
Vol 47 ◽  
pp. 710-711
Author(s):  
R.E. Omlor ◽  
P. F. Lloyd
Keyword(s):  
Carbon Fibers ◽  
Materials Science ◽  
Cutting Speed ◽  
Specimen Preparation ◽  
Main Concern ◽  
Ion Milling ◽  
Semiconductor Chip ◽  
Rapidly Solidified ◽  
Preparation Techniques ◽  
Diamond Knife

Standard sample preparation techniques of various metals, composites, ceramics and polymer specimens can be very time consuming (such as dimpling and ion milling etc.), yet still introroduce artifacts during specimen preparation. With many of these materials numerous hours and sometimes even days can be spent preparing samples for TEM studies. In the past, ultramicrotomy has been used primarily for biological applications, but over the years has been tried on various polymers, metal and ceramic powders, oxide layers, etc. The main concern has been deformation introduced to the specimen while cutting. This study will demonstrate successful ultramicrotomy over a variety of non-biological specimens.Materials chosen for this experiment consist of Rapidly Solidified (RS) Al-V powders, P-120 Carbon fibers, Silicon Carbide (MMC) fibers, Kevlar and an IC semiconductor chip. Routine SEM micrographs were taken of all material as-received. All the specimens were embedded using a low viscoscity resin, L. R. White (hard grade). They were microtomed with a diamond knife at a 55-60° cutting angle using an AO/Reichert Ultracut Ultramicrotome with a slow cutting speed of 0.4 mm/sec which obtained the best results. All sections were picked up on Hex 700TB Ni grids.

Energy Filtered Electron Backscattering Images of 10-nm NbC and AIN Precipitates in Steels Computed by Monte Carlo Simulations

1996 ◽  
Vol 54 ◽  
pp. 150-151
Author(s):  
Raynald Gauvin ◽  
Dominique Drouin ◽  
Pierre Hovington
Keyword(s):  
Monte Carlo ◽  
Electron Beam ◽  
Electron Microscope ◽  
Materials Science ◽  
Specimen Preparation ◽  
Backscattered Electrons ◽  
Electron Backscattering ◽  
Transmission Electron ◽  
Properties Of Materials ◽  
Scanning Electron

In modern materials science, it is important to improve the resolution of the Scanning Electron Microscope (SEM) because small phases play a crutial role in the properties of materials. The Transmission Electron Microscope (TEM) is the tool of choice for imaging small phases embedded in a given matrix. However, this technique is expensive and also is slow owing to specimen preparation. In this context, it is important to improve spatial resolution of the SEM.In electron backscattering images, it is well know that the backscattered electrons have an energetic distribution when they escape the specimen.The electrons having loss less energy are those which have travelled less in the specimen and thus escape closer to the electron beam. So, in filtering the energy of the backscattering electron and keeping those which have loss only a small amount of energy to create the image, a significant improvement of the resolution of such images is expected. New detectors are now under development to take advantage of this technique of imaging.

Instrumentation and Computation

1990 ◽  
Vol 48 (1) ◽  
pp. 2-3
Author(s):  
P.B. Hirsch
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Materials Science ◽  
Image Interpretation ◽  
Specimen Preparation ◽  
Scanning Tunnelling Microscope ◽  
Transmission Electron ◽  
Wide Range ◽  
Electron Microscopes ◽  
Types Of Information

The benefit to society arising from developments in instrumentation and computation can be judged primarily by the advances in knowledge and understanding generated by their application in different branches of science, covered in the other papers in this symposium. Without advances in instrumentation none of these advances is possible; developments in instrumentation and in image interpretation are therefore fundamental to and precede scientific advances in fields in which knowledge of structure is important. There is little doubt that the revolutionary first step was the development of the transmission electron microscope (TEM) in 1931 by Ernst Ruska; a second was the development of the scanning electron microscope (SEM); and the third the introduction of the scanning tunnelling microscope (STM) for high resolution surface imaging, by Binnig and Rohrer.The TEM and SEM have undergone continuous developments over the last 50 years or so, and have had a far-reaching impact in a wide range of disciplines; the STM is a relative newcomer but no doubt it too will have an increasing impact in furthering our understanding of solids and surfaces in particular. Once the basic instruments became available subsequent developments have been driven by the demands of the scientific disciplines in which these instruments have been applied. Many of the new developments in instrumentation and interpretation have been pioneered by the users themselves, and these in turn have led to modifications in commercial instruments to make such advances in technique available to the user community as a whole. Other developments have been initiated directly by the manufacturers as a result of a perceived need. There has been and continues to be a close interaction between the developers of hardware (not only of electron microscopes but also of ancillary equipment, e.g. microanalysis attachments, image processing equipment, specialist specimen stages, and specimen preparation facilities) and the users, leading to extensions in the range of applications and the types of information which can be obtained by electron microscopy. The following examples from the developments of electron microscopy in Materials Science illustrate these interactions and the particular advances arising from specific developments:

Reflections on the Use of Microtomy for Materials Science Specimen Preparation

1997 ◽  
Vol 3 (3) ◽  
pp. 239-260 ◽  
Author(s):  
H.K. Plummer
Keyword(s):  
Carbon Fibers ◽  
Materials Science ◽  
Ford Motor Company ◽  
Aluminum Surface ◽  
Specimen Preparation ◽  
Exhaust Catalysts ◽  
The Many ◽  
Rapidly Solidified ◽  
Preparation Techniques ◽  
Insight Into

Abstract: Since 1972 the author and colleagues at Ford Motor Company have been publishing results of materials analyses which were obtained using ambient temperature or cryomicrotomy as one of the sample preparation techniques. Generally two types of sectioning, thin and ultrathin, were pursued for light-optical and electron-optical microscopy, respectively. These papers include the study of the following materials, which have been separated into nine classes: polymer composites, polymer blends, reverse osmosis membranes, carbon fibers, elastomers, automotive exhaust catalysts, aluminum surface coatings, aluminum alloy automotive wheels, and rapidly solidified aluminum alloys. This review is not intended to reiterate the conclusions of these prior publications but will provide the reader with an insight into the many ways microtomy can be used for materials studies.

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