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.

A Scanning Electron Microscope from Hitachi

1969 ◽  
Vol 27 ◽  
pp. 88-89
Author(s):  
Yoshirou Onuma ◽  
Tatsuo Hujiyasu ◽  
Yukio Kakinuma
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Mechanical Vibration ◽  
Electron Gun ◽  
Objective Lens ◽  
Lens System ◽  
Beam Path ◽  
External View ◽  
Electrical Fields ◽  
Scanning Electron

Hitachi, Limited has recently completed the development of a commercial scanning electron microscope, the features of which are discussed herein. Fig. 1 is an external view of the instrument.Lens SystemA three-stage reduction lens system is employed to obtain a short electron beam path. This minimizes the effects of any external electromagnetic or stray electrical fields as well as mechanical vibration or shock. Axial alignment is easily accomplished by transverse adjustment of the electron gun and lens system. Aperture plates with different hole sizes are provided in the condenser lens, deflection coil, and on the principal plane of the objective lens. The apertures are easily removed for cleaning. The electromagnetic stigmator is located outside the objective lens to facilitate removal for cleaning. Resolution of 200Å~250Å is guaranteed.

Contrast Effects in High Resolution, Low Voltage SEM

1974 ◽  
Vol 32 ◽  
pp. 452-453
Author(s):  
L. M. Welter
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Low Voltage ◽  
Electron Source ◽  
Scanning Microscopy ◽  
Contrast Effects ◽  
Probe Current ◽  
Scanning Electron

A scanning electron microscope using a field emission electron source and a single electromagnetic lens can produce a resolution of less than 180Å using an accelerating voltage of only 900v. High resolution, low voltage (0.1-2kV) scanning microscopy offers a number of advantages over the use of higher accelerating voltages. Specimen damage may be reduced because the power (P≃IV) which must be absorbed by the specimen for operation at a given probe current (I) is decreased in proportion to the reduction in accelerating voltage (V).

Electron-optical design of a high-resolution objective lens for low-voltage Scanning Electron Microscope of biological applications

1992 ◽  
Vol 50 (2) ◽  
pp. 950-951
Author(s):  
J. Ximen ◽  
P. S. D. Lin ◽  
J. B. Pawley ◽  
M. Schippert
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Surface Characterization ◽  
Low Voltage ◽  
Optical Design ◽  
Objective Lens ◽  
Magnetic Lens ◽  
Voltage Scanning ◽  
Scanning Electron

By providing higher image contrast and reduced charging artifacts, the low voltage scanning electron microscope (LVSEM) is a valuable tool for surface characterization, of particular importance on nonconductive material such as biological specimens. Several SEM designs optimized for use at low voltage have been proposed.Recently, we have designed a new high resolution LVSEM using a field emission gun. The key problem is to decrease both the spherical and chromatic aberration coefficients by using a magnetic lens of small bore diameters(5mm and 10mm) and a narrow gap (7.5mm) (FIG. 1). In our first design, the magnetic lens is built around the side-entry stage of a Philips 300kV TEM and performs as well as that in the present Hitachi SEM H-900 or H-900S. Its simple design has been chosen for reliability and flexibility in farbrication.

Development of an Ultrahigh-Vacuum Ultrahigh-Resolution Scanning Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 440-441
Author(s):  
T. Tomita ◽  
Y. Kokubo ◽  
Y. Harada ◽  
H. Daimon ◽  
S. Ino
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Analytical Electron Microscopy ◽  
Ultrahigh Vacuum ◽  
Specimen Preparation ◽  
Lattice Image ◽  
Ultrahigh Resolution ◽  
Electron Microscopes ◽  
Scanning Electron

An ultrahigh-vacuum (UHV) ultrahigh-resolution (UHR) 100kV scanning electron microscope with a UHV specimen preparation chamber has been developed for in situ observation of clean specimen surfaces. The measured vacuum in the specmen area was about 2.2 × 10-8 Pa, and a 0.14nm lattice image of Au (220) was observed.Field emission scanning electron microscopes have been developed for the past ten years for sub-nanometer analysis. However, in recent analytical electron microscopy of so-called “new materials” such as ceramics and semiconductors, half nanometer analysis in UHV has become extremely important for materials characterization.Figure 1 shows an external view of the microscope. The microscope column and it’s control console are shown at the left and right, respectively. The seales of microscope column are only metal 0 rings and Cu-gaskets, and automatic bake-out is carried out at about 160°C.Figure 2 shows the electron optics of the system. A thermal assisted field emission gun (TFEG) with a W (100) emitter was used as a high-brightness gun, thus ensuring a brightness of 2 × 108 A/cm2 · str at 100 kV.

A Miniature Low Voltage SEM with High Resolution

1999 ◽  
Vol 5 (S2) ◽  
pp. 322-323
Author(s):  
J.M. Krans ◽  
T.L. van Rooy
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Low Voltage ◽  
Optical Systems ◽  
Objective Lens ◽  
Secondary Electrons ◽  
Voltage Imaging ◽  
Resolution Imaging ◽  
Scanning Electron

Miniaturization of electron optical systems has gained much interest over the last decade [1,2]. In a scanning electron microscope, downscaling of the column dimensions is expected to allow for high resolution imaging at low electron beam voltage. Main advantages of low voltage imaging are lower penetration depth, increased secondary electron yield, less specimen charging and better topographic contrast [3].We have developed a miniature scanning electron microscope (SEM) with high resolution at low beam energies. The outer dimensions of the miniaturized SEM column are 25 mm diameter and 95 mm length, including conventional field emitter electron source module. The column prototype is shown in Fig. 1. The size reduction has been achieved by the exclusive implementation of electrostatic column components. Electron optical simulations indicate that the retarding objective lens of the miniature SEM allows for a probe resolution of 3 nm at 1 keV beam energy. The secondary electrons are collected at an internal scintillator detector.

scholarly journals Specimen Preparation for Condoms

2007 ◽  
Vol 15 (5) ◽  
pp. 40-41 ◽  
Author(s):  
Gan Phay Fang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Polymer Material ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Sem Imaging ◽  
Preparation Techniques ◽  
Scanning Electron

Specimen preparation techniques for Scanning Electron Microscope (SEM) imaging of condoms as reported by Rosenzweig et al revealed a variety of artifacts. The artifacts were classified as ridging, cracking and melting. The purpose of this article is to introduce a simple specimen preparation technique for condoms to be evaluated via SEM without any surface artifacts. This technique involves the use of two chrome washers to sandwich the condom. The sandwiched condom specimen is then subjected to coating before mounting on an aluminium stub. The execution of this technique requires patience and practice so as not to damage the condom. The method may be applied to any similar polymer material.

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