Development of a Field Emission Stem and its Application to Element Analysis

1976 ◽  
Vol 34 ◽  
pp. 524-525
Author(s):  
S. Nomura ◽  
H. Todokoro ◽  
T. Komoda
Keyword(s):  
Field Emission ◽  
Collection Efficiency ◽  
Scanning Transmission Electron Microscope ◽  
Electron Gun ◽  
High Signal ◽  
Element Analysis ◽  
Signal Collection ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Tungsten Tip

The Scanning Transmission Electron Microscope (STEM) has made possible specimen observation with a number of advantages such as high signal collection efficiency. In addition, STEM also permits element analysis of micro-areas, when it is used in conjunction with X-ray and/or electron spectrometers. These advantages become more effective by using a high brightness electron gun.The authors have developed a field emission STEM. The schematic diagram of the instrument is shown in Fig. 1. Electrons emitted from the tungsten tip are focused on a specimen by one electro-static and two magnetic lenses. The field emission tip is surrounded by ion pumps, and the vacuum of the gun chamber is maintained at better than 5xlO-10torr.

To What Extent are Inelastically Scattered Electrons Useful in the Stem?

1973 ◽  
Vol 31 ◽  
pp. 286-287 ◽  
Author(s):  
H. Rose
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Electron Correlation ◽  
Quantum Noise ◽  
Collection Efficiency ◽  
Scanning Transmission Electron Microscope ◽  
Electron Cloud ◽  
Scanning Time ◽  
Transmission Electron ◽  
Scanning Transmission

The scanning transmission electron microscope offers the possibility of utilizing inelastically scattered electrons. Use of these electrons in addition to the elastically scattered electrons should reduce the scanning time (dose) Which is necessary to keep the quantum noise below a certain level. Hence it should lower the radiation damage. For high resolution, Where the collection efficiency of elastically scattered electrons is small, the use of Inelastically scattered electrons should become more and more favorable because they can all be detected by means of a spectrometer. Unfortunately, the Inelastic scattering Is a non-localized interaction due to the electron-electron correlation, occurring predominantly at the circumference of the atomic electron cloud.

Description of a New High Resolution Scanning Transmission EM

1972 ◽  
Vol 30 ◽  
pp. 418-419
Author(s):  
Michael Beer ◽  
J. W. Wiggins ◽  
David Woodruff ◽  
Jon Zubin
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Energy Dispersive Spectrometer ◽  
Scanning Transmission Electron Microscope ◽  
Objective Lens ◽  
Condenser Lens ◽  
Transmission Electron ◽  
Pattern Size ◽  
Scanning Transmission ◽  
Under Construction

A high resolution scanning transmission electron microscope of the type developed by A. V. Crewe is under construction in this laboratory. The basic design is completed and construction is under way with completion expected by the end of this year.The optical column of the microscope will consist of a field emission electron source, an accelerating lens, condenser lens, objective lens, diffraction lens, an energy dispersive spectrometer, and three electron detectors. For any accelerating voltage the condenser lens function to provide a parallel beam at the entrance of the objective lens. The diffraction lens is weak and its current will be controlled by the objective lens current to give an electron diffraction pattern size which is independent of small changes in the objective lens current made to achieve focus at the specimen. The objective lens demagnifies the image of the field emission source so that its Gaussian size is small compared to the aberration limit.

scholarly journals FEI Titan 80-300 STEM

2016 ◽  
Vol 2 ◽  
Author(s):  
Marc Heggen ◽  
Martina Luysberg ◽  
Karsten Tillmann
Keyword(s):  
Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
Electron Gun ◽  
Lens System ◽  
Scanning Transmission Electron ◽  
System A ◽  
Transmission Electron ◽  
The World ◽  
Scanning Transmission ◽  
Electron Microscopes

The FEI Titan 80-300 STEM is a scanning transmission electron microscope equipped with a field emission electron gun, a three-condenser lens system, a monochromator unit, and a Cs probe corrector (CEOS), a post-column energy filter system (Gatan Tridiem 865 ER) as well as a Gatan 2k slow scan CCD system. Characterised by a STEM resolution of 80 pm at 300 kV, the instrument was one of the first of a small number of sub-ångström resolution scanning transmission electron microscopes in the world when commissioned in 2006.

scholarly journals Advances and Applications of Atomic-Resolution Scanning Transmission Electron Microscopy

2021 ◽  
Vol 27 (5) ◽  
pp. 943-995
Author(s):  
Jingyue (Jimmy) Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Field Emission ◽  
Scanning Transmission Electron Microscopy ◽  
Electron Gun ◽  
Atomic Resolution ◽  
Single Atom ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

Although scanning transmission electron microscopy (STEM) images of individual heavy atoms were reported 50 years ago, the applications of atomic-resolution STEM imaging became wide spread only after the practical realization of aberration correctors on field-emission STEM/TEM instruments to form sub-Ångstrom electron probes. The innovative designs and advances of electron optical systems, the fundamental understanding of electron–specimen interaction processes, and the advances in detector technology all played a major role in achieving the goal of atomic-resolution STEM imaging of practical materials. It is clear that tremendous advances in computer technology and electronics, image acquisition and processing algorithms, image simulations, and precision machining synergistically made atomic-resolution STEM imaging routinely accessible. It is anticipated that further hardware/software development is needed to achieve three-dimensional atomic-resolution STEM imaging with single-atom chemical sensitivity, even for electron-beam-sensitive materials. Artificial intelligence, machine learning, and big-data science are expected to significantly enhance the impact of STEM and associated techniques on many research fields such as materials science and engineering, quantum and nanoscale science, physics and chemistry, and biology and medicine. This review focuses on advances of STEM imaging from the invention of the field-emission electron gun to the realization of aberration-corrected and monochromated atomic-resolution STEM and its broad applications.

Studies of Aggregates of Two Muscle Proteins with Scanning Transmission and Conventional Transmission Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 600-601 ◽  
Author(s):  
M. K. Lamvik ◽  
M. S. Isaacson ◽  
A. V. Crewe
Keyword(s):  
Striated Muscle ◽  
Collection Efficiency ◽  
Scanning Transmission Electron Microscope ◽  
High Contrast ◽  
Muscle Proteins ◽  
Native Structure ◽  
Preparation Methods ◽  
Signal Selection ◽  
Transmission Electron ◽  
Scanning Transmission

Studies of the structures of various aggregates of proteins from vertebrate striated muscle have begun, using in particular the scanning transmission electron microscope (STEM). The high collection efficiency of this microscope has been noted elsewhere and the contrast advantage and signal selection capabilities have been demonstrated.Although the instrument can produce high contrast images of unstained and unfixed biological material, it is not clear which preparation methods might maintain the native structure of such material. So the study begins on familiar ground with conventionl negatively stained preparations, While later steps will include less conventional methods.Rabbit tropomyosin Mg-tactoids in suspension were received from Dr. Carolyn Cohen (of Children's Cancer Research Foundation, Boston). The tactoids have a primary periodicity of 395 Å. Isolated myofibrils were obtained from Joseph Etlinger (of this University); myosin was extracted from them by a method similar to that of Dow and Stracher.

Alignment of low-dose STEM images of unstained macromolecules

1984 ◽  
Vol 42 ◽  
pp. 162-163
Author(s):  
J. F. Hainfeld ◽  
P. S. Furcinitti ◽  
J. S. Wall
Keyword(s):  
Low Dose ◽  
Collection Efficiency ◽  
Scanning Transmission Electron Microscope ◽  
Single Particles ◽  
Low Contrast ◽  
Damage Rate ◽  
Software Packages ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Beam Damage

Several studies of molecular structure have successfully employed computer techniques to align images of single particles. Image processing software packages (e.g., P. R. Smith's MDPP system and J. Frank's SPIDER system) have also been developed to facilitate this work. Due to the low contrast and high beam damage rate involved in the use of unstained specimens, most single particle (i.e., non-crystalline) image alignment has been of negatively stained specimens. The scanning transmission electron microscope (STEM), which has a linear transfer function at high resolution rather than the oscillating one inherent to CEMs, operationally overcomes these limitations by providing low dose, high contrast images of unstained material with high collection efficiency.

High-resolution scanning electron microscopy

1987 ◽  
Vol 45 ◽  
pp. 530-533
Author(s):  
T. Nagatani
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Field Emission ◽  
Scanning Transmission Electron Microscope ◽  
Objective Lens ◽  
Second Development ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Scanning Electron

Although the main development of scanning electron microscopy (SEM) has been accomplished mostly by the Cambridge group and it has not been changed so much for about two decades, it should be noted that there have been two important developments to pursuing high resolution of better than 1nm.Most notably, use of a field emission gun developed by Crewe et al for the scanning transmission electron microscope (STEM) to form a fine electron beam has been most effective in SEMs due to its high brightness and low energy spread. Thus, several models of field emission (FE) SEMs have been developed in the early ’70s and commercialized with a resolution of 2∼3nm at around 30kV.The second development is to use a highly excited objective lens. The specimen has to be set inside the pole-pieces (so-called “in-lens” type).

Stabilising a Peels spectrometer

1994 ◽  
Vol 52 ◽  
pp. 498-499
Author(s):  
D. McMullan
Keyword(s):  
Electron Energy ◽  
Scanning Transmission Electron Microscope ◽  
Energy Spread ◽  
Electron Gun ◽  
Limiting Factor ◽  
Cavendish Laboratory ◽  
Transmission Electron ◽  
Alternative Approach ◽  
Scanning Transmission ◽  
Electron Image

The resolution of a parallel recording electron energy loss spectrometer (PEELS) depends critically on the stabilities of the power supplies to the microscope column and the spectrometer over the period of the exposure. They may be the limiting factor in a dedicated scanning transmission electron microscope (STEM) with a field-emission electron gun (FEG), and improving them so that they are sufficiently stable can be a difficult task.An alternative approach is to compensate for any drift by deflecting the electron image of the spectrum leaving the spectrometer. The amount of deflection is that required to keep the zero-loss peak at a fixed position relative to the recording system. Such a stabiliser is being developed in the Microstructural Physics (MP) Group at the Cavendish Laboratory and a progress report is given here.The MP STEM is a VG Microscopes HB501 fitted with an Isaacson electron spectrometer. The normal accelerating potential is 100 kV and the FEG has an electron energy spread of about 0.25 eV. The spectrometer gives a dispersion of 1.8 pm per eV at the slit and from the evidence of very short exposures its resolution is adequate to match the FEG energy-spread in the absence of drift. A PEELS system with 3 quadrupoles and a YAG + CCD detector has been added, but the slit has been retained.

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