scholarly journals Field-Emission Scanning Electron Microscope as a Tool for Large-Area and Large-Volume Ultrastructural Studies

Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3390
Author(s):  
Bogdan Lewczuk ◽  
Natalia Szyryńska
Keyword(s):  
Field Emission ◽  
Imaging Techniques ◽  
Solid Substrate ◽  
Large Area ◽  
En Bloc ◽  
Advantages And Disadvantages ◽  
Ultrastructural Studies ◽  
Array Tomography ◽  
Electron Microscopes ◽  
Scanning Electron

The development of field-emission scanning electron microscopes for high-resolution imaging at very low acceleration voltages and equipped with highly sensitive detectors of backscattered electrons (BSE) has enabled transmission electron microscopy (TEM)-like imaging of the cut surfaces of tissue blocks, which are impermeable to the electron beam, or tissue sections mounted on the solid substrates. This has resulted in the development of methods that simplify and accelerate ultrastructural studies of large areas and volumes of biological samples. This article provides an overview of these methods, including their advantages and disadvantages. The imaging of large sample areas can be performed using two methods based on the detection of transmitted electrons or BSE. Effective imaging using BSE requires special fixation and en bloc contrasting of samples. BSE imaging has resulted in the development of volume imaging techniques, including array tomography (AT) and serial block-face imaging (SBF-SEM). In AT, serial ultrathin sections are collected manually on a solid substrate such as a glass and silicon wafer or automatically on a tape using a special ultramicrotome. The imaging of serial sections is used to obtain three-dimensional (3D) information. SBF-SEM is based on removing the top layer of a resin-embedded sample using an ultramicrotome inside the SEM specimen chamber and then imaging the exposed surface with a BSE detector. The steps of cutting and imaging the resin block are repeated hundreds or thousands of times to obtain a z-stack for 3D analyses.

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.

Digital imaging with field emission scanning electron microscopes (FSEM)

1992 ◽  
Vol 50 (2) ◽  
pp. 1276-1277
Author(s):  
Klaus-Ruediger Peters ◽  
William H. Martin ◽  
Eisaku Oho
Keyword(s):  
Field Emission ◽  
Image Acquisition ◽  
Scanning Electron Micrographs ◽  
Output Quality ◽  
Plain Paper ◽  
Electron Microscopes ◽  
Information Image ◽  
Scanning Electron Microscopes ◽  
And Storage ◽  
Scanning Electron

Digital image acquisition and display of field emission scanning electron micrographs face limitations in terms of detail recognition, sampling of high resolution information, image output and storage space for high pixel density images. The image acquisition and image output of a JEOL JSEM-890 “in lens” field emission SEM were digitized and several approaches for adequate access to the scanned electron probe data have been developed. Images are acquired digitally in 3×4 VGA format (in multiples of 640×490 pixels) and stored in a RECOGNITION CONCEPTS INC. image processor (Trapix Plus). The images are displayed on workstation monitors with 1280×1024 format (HITACHI CM2085MU), and image documentation is done by several techniques of varying output quality. Low quality image documentation on plain paper can be obtained using a laser jet printer (HEWLETT PACKARD: Laser Jet III). High quality output is provided by a video printer utilizing special but inexpensive paper (SEIKOSHA VP350H). In addition, conventional analog CRT output and CRT photography on 4×5 inch POLAROID (Type 55 Positive/Negative) film is used.

scholarly journals THE EFFECT OF ADSORBENT AGENTS: SILICA, ANDISOL, LECA, ANTHRACITE, AND ACTIVATED CARBON ON POLLUTANT UPTAKE IN THE CITARUM RIVER (Pengaruh agen penjerap silika, andisol, LECA, antrasit, dan karbon aktif terhadap penjerapan polutan di Sungai Citarum)

2021 ◽  
Vol 5 (2) ◽  
pp. 105-120
Author(s):  
Fahriya Puspita Sari ◽  
◽  
Nissa Nurfajrin Solihat ◽  
Muhammad Sholeh ◽  
Lucky Risanto ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Activated Carbon ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Field Emission ◽  
Fourier Transform Infrared ◽  
Nephelometric Turbidity Unit ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

Sungai Citarum merupakan sungai terpanjang dan terbesar di Jawa Barat, Indonesia yang mempunyai fungsi vital sebagai sumber air. Pengolahan air sungai Citarum sebelum disalurkan ke masyarakat diperlukan untuk menghilangkan pengotor karena kandungan pengotor pada air sungai Citarum melebihi batas ambang yang dipersyaratkan untuk air konsumsi. Saat ini proses penjerapan atau adsorpsi merupakan proses yang umum digunakan pada perusahaan pegolahan air karena efektifitasnya. Pada penelitian ini, efektifitas lima agen penjerap yaitu silika, andisol, hidroton, antrasit, karbon aktif telah dievaluasi dengan perbedaan rasio padatan dan larutan, dan waktu kontak. Setelah pengolahan, kekeruhan dan logam berat dalam air dianalisa. Karakteristik permukaan, gugus fungsi, dan luas permukaan dari kelima agen penjerap dianalisa masing-masing menggunakan FE-SEM (Field Emission - Scanning Electron Microscopes), FTIR (Fourier Transform Infrared Spectroscopy), dan analisa luas permukaan BET (Brunauer-Emmett-Teller). Hasil analisa menunjukan bahwa masing-masing andisol dan LECA menurunkan kekeruhan dari air citarum dari 21.3 NTU (Nephelometric Turbidity Unit) menjadi 1.23 dan 2.52 NTU setelah waktu kontak 10 menit. Karbon aktif membutuhkan waktu 10 menit lebih lama untuk menurunkan kekeruhan menjadi 2.26 NTU akan tetapi karbon aktif memiliki luas permukaan yang paling tinggi yaitu 548.310 (m2/g). Luas permukaan berkaitan dengan hasil FE-SEM dimana karbon aktif memiliki pori yang teratur dan berukuran besar. Pada umumnya, andisol, LECA, dan karbon aktif telah berhasil menurunkan kekeruhan air Sungai Citarum yang berkaitan dengan luas permukaan partikelnya.

Direct Defect Imaging in the High Resolution Sem

1990 ◽  
Vol 183 ◽  
Author(s):  
David C Joy
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
High Performance ◽  
Necessary Conditions ◽  
Electron Channeling ◽  
Electron Microscopes ◽  
Crystallographic Defects ◽  
Scanning Electron Microscopes ◽  
Defect Imaging ◽  
Scanning Electron

AbstractThe theory of imaging crystallographic defects in solid specimens through the use of electron channeling contrast is reviewed and the necessary conditions for observation are deduced. It is shown that current high performance field emission scanning electron microscopes can meet these requirements and produce dislocation images from suitable materials.

A New High Resolution Field Emission SEM with Variable Pressure Capabilities

2001 ◽  
Vol 7 (S2) ◽  
pp. 880-881 ◽  
Author(s):  
Peter Gnauck ◽  
Volker Drexel ◽  
J. Greiser
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Low Voltage ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Chamber Pressure ◽  
Variable Pressure ◽  
Natural State ◽  
Electron Microscopes ◽  
Scanning Electron

To examine non conductive samples in their natural state (i.e. without significant sample preparation) at high resolution in the SEM the technique of low voltage field emission scanning electron microscopy (LVFESEM) is used. Due to the limitation in accelerating voltage (U<1kV) this technique is limited in respect of chemical analysis. Furthermore it is not possible to examine humid and outgassing samples in high vacuum. in recent years the application of variable pressure scanning electron microscopes (VPSEM) became an important technique in materials science as well as in life science. Due to the capability of maintaining a high chamber pressure humid, outgassing and non-conductive samples, can be examined in their natural state without significant sample modification or preparation. Especially compound materials with different electron yields can be imaged without any charging effects (Fig. 2), [2]. This paper describes a high resolution field emission electron microscope, that combines low voltage and variable pressure capabilities.The high pressure capabilities of the instrument are realized by eliminating the high vacuum requirements of SEM in the microscope chamber. This is done by separating the vacuum environment in the chamber from the ultra high vacuum environment in the gun area.

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.

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