Detection efficiency and estimation of the performance of high voltage STEM

1978 ◽  
Vol 36 (1) ◽  
pp. 84-85
Author(s):  
A. Ishikawa ◽  
C. Morita ◽  
M. Hibino ◽  
S. Maruse
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Radiation Damage ◽  
High Voltage ◽  
Detection Efficiency ◽  
Beam Current ◽  
High Energy ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Transmission Electron

One of the problems which are met in conventional transmission electron microscopy (CTEM) at high voltages is the reduction of the sensitivity of photographic films for high energy electron beams, resulting in the necessity of using high beam current. This cancels out an advantage of high voltage electron microscopy which is otherwise expected from the reduction of the inelastic scattering in the specimen, that is the reduced radiation damage of the specimen during observations. However, it is expected that the efficiency of the detector of scanning transmission electron microscopy (STEM) can be superior to that of CTEM, since the divergence of the electron beam in the detecting material does not affect the quality of the image. In addition to observation with less radiation damage, high voltage STEM with high detection efficiency is very attractive for observations of weak contrast objects since the enhancement of the contrast (which is an important advantage of STEM) is easily realized electrically.

scholarly journals Some Current and Future Trends of High Voltage Transmission Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 2-3
Author(s):  
Gareth Thomas
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Materials Science ◽  
Future Trends ◽  
Light Elements ◽  
Special Effects ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Transmission Electron ◽  
Resolution Level

The Optimum Voltages for Electron Microscopy – The advantages of high voltage electron microscopy are now well established, and many applications, such as use of environmental cells both in metallurgy and biology, are now possible. However recent experiments at Toulouse indicate that except for light elements, there is no appreciable gain in transmission for a given resolution level as the energy is increased above 1 MeV (see Fig. 1). These results are not as optimistic as theory might indicate. Special effects such as critical voltages above 1 MeV are of interest, but knock-on radiation damage imposes limitations on many applications. Thus it would appear that 1 MeV is a reasonable upper limit for most applications in materials science.

scholarly journals Single-particle cryo-EM: alternative schemes to improve dose efficiency

2021 ◽  
Vol 28 (5) ◽  
pp. 1343-1356
Author(s):  
Yue Zhang ◽  
Peng-Han Lu ◽  
Enzo Rotunno ◽  
Filippo Troiani ◽  
J. Paul van Schayck ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Radiation Damage ◽  
Information Transfer ◽  
Structural Information ◽  
High Energy ◽  
Phase Plate ◽  
Transmission Electron ◽  
Dose Efficiency ◽  
The Individual

Imaging of biomolecules by ionizing radiation, such as electrons, causes radiation damage which introduces structural and compositional changes of the specimen. The total number of high-energy electrons per surface area that can be used for imaging in cryogenic electron microscopy (cryo-EM) is severely restricted due to radiation damage, resulting in low signal-to-noise ratios (SNR). High resolution details are dampened by the transfer function of the microscope and detector, and are the first to be lost as radiation damage alters the individual molecules which are presumed to be identical during averaging. As a consequence, radiation damage puts a limit on the particle size and sample heterogeneity with which electron microscopy (EM) can deal. Since a transmission EM (TEM) image is formed from the scattering process of the electron by the specimen interaction potential, radiation damage is inevitable. However, we can aim to maximize the information transfer for a given dose and increase the SNR by finding alternatives to the conventional phase-contrast cryo-EM techniques. Here some alternative transmission electron microscopy techniques are reviewed, including phase plate, multi-pass transmission electron microscopy, off-axis holography, ptychography and a quantum sorter. Their prospects for providing more or complementary structural information within the limited lifetime of the sample are discussed.

Progress in environmental high-voltage transmission electron microscopy for nanomaterials

2020 ◽  
Vol 378 (2186) ◽  
pp. 20190602
Author(s):  
Nobuo Tanaka ◽  
Takeshi Fujita ◽  
Yoshimasa Takahashi ◽  
Jun Yamasaki ◽  
Kazuyoshi Murata ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Voltage ◽  
High Energy ◽  
Transmission Electron ◽  
Recent Developments ◽  
In Situ Observations ◽  
High Voltage Transmission ◽  
And Function

A new environmental high-voltage transmission electron microscope (E-HVEM) was developed by Nagoya University in collaboration with JEOL Ltd. An open-type environmental cell was employed to enable in-situ observations of chemical reactions on catalyst particles as well as mechanical deformation in gaseous conditions. One of the reasons for success was the application of high-voltage transmission electron microscopy to environmental (in-situ) observations in the gas atmosphere because of high transmission of electrons through gas layers and thick samples. Knock-on damages to samples by high-energy electrons were carefully considered. In this paper, we describe the detailed design of the E-HVEM, recent developments and various applications. This article is part of a discussion meeting issue ‘Dynamic in situ microscopy relating structure and function'.

Observations on Developing Blood Vessels in Rat Spinal Cord—A High Voltage Electron Microscopy Study

1974 ◽  
Vol 32 ◽  
pp. 66-67
Author(s):  
Richard S. Hannah
Keyword(s):  
Electron Microscopy ◽  
Spinal Cord ◽  
High Voltage ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
High Voltage Electron Microscopy ◽  
Thin Sections ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Transmission Electron

The formation of junctional complexes between endothelial cell processes was examined in rat spinal cords, from age birth to six weeks. Segments of spinal cord were removed from the region of the cervical enlargement and fixed. For comparative purposes, animals from each time group were subdivided into groups, fixed by either immersion or perfusion with an aldehyde combination in sodium cacodylate buffer and embedded in Araldite. Thin sections were examined by conventional transmission electron microscopy. Thick sections (0.5μ - 1.0μ) were stained with uranyl magnesium acetate for four hours at 60°C and lead citrate for 30 mins. and examined in the AEI Mark II High Voltage Electron Microscope.

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