TEM introduction
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This limit is known as resolution, limit of resolution or resolving power of microscopy.
The resolution of the microscopy is the smallest separation of two points in the object which may be distinctly reproduced in the image.
An Introduction to Transmission Electron Microscopy (TEM)/Scanning Transmission
Electron Microscopy (STEM)
• What is a TEM?
• How it works - gun, lenses, specimen stage
• What can a TEM do?
• Imaging and diffraction Imaging-diffraction and phase contrast Diffraction-Selected area electron diffraction (SAED) Chemical analysis EDS, Electron Energy Loss Spectroscopy (EELS)
Basic features of A Modern TEM
Column
CBaidu Nhomakorabea200 (200kV)
Electron Gun
Condenser Lens
Objective Lens
SAD Aperture
Binocular
TV Monitor Camera Chamber
EDS Detector
Specimen Holder Magnifying Lenses Viewing Chamber
Introduction to TEM
Brief introduction of
TEM
(Transmission Electron Microscopy)
Resolving Power
The instrument that permits us to show detail finer than that which can be seen with naked eye is of great value.
• A vacuum system is necessary to remove interfering air molecules from the column of the electron microscope. In the descriptions that follow, the systems will be considered from the top of the microscope to the bottom.
Optical microscopy was discovered in seventeenth century that started new era of investigation.
E. Abbe was the first to explain on the basis of diffraction effects that there is a limit to the smallness of the objects which might be produced by lens.
Approx. Cost: $4,000,000
A simple analogue
A better comparison
Basic Systems Making Up a Transmission
Electron Microscope
• The imaging system includes the objective, intermediate, and projector lenses that are involved in forming, focusing, and magnifying the image on the viewing screen as well as the camera that is used to record the image.
Vacuum
The electron microscope is built like a series of vessels connected by pipes and valves separate all the vessels from each other.
Why TEM?
The uniqueness of TEM is the ability to obtain morphological (grain size, grain boundary and interface, secondary phase and distribution, defects and their nature, etc.), crystallographic, atomic structural and microanalytical such as chemical composition (at nm scale), bonding (distance and angle), electronic structure, coordination number data from the sample. TEM is the most efficient and versatile technique for the characterization of materials.
Table. Electron properties as a function of accelerating voltage.
Accelerating voltage (kV) 100 120 200 300 400 1000
Wavelength (nm) 0.00370 0.00335 0.00251 0.00197 0.00164 0.00087
The resolution of the microscopy is the smallest separation of two points in the object which may be distinctly reproduced in the image.
An Introduction to Transmission Electron Microscopy (TEM)/Scanning Transmission
Electron Microscopy (STEM)
• What is a TEM?
• How it works - gun, lenses, specimen stage
• What can a TEM do?
• Imaging and diffraction Imaging-diffraction and phase contrast Diffraction-Selected area electron diffraction (SAED) Chemical analysis EDS, Electron Energy Loss Spectroscopy (EELS)
Basic features of A Modern TEM
Column
CBaidu Nhomakorabea200 (200kV)
Electron Gun
Condenser Lens
Objective Lens
SAD Aperture
Binocular
TV Monitor Camera Chamber
EDS Detector
Specimen Holder Magnifying Lenses Viewing Chamber
Introduction to TEM
Brief introduction of
TEM
(Transmission Electron Microscopy)
Resolving Power
The instrument that permits us to show detail finer than that which can be seen with naked eye is of great value.
• A vacuum system is necessary to remove interfering air molecules from the column of the electron microscope. In the descriptions that follow, the systems will be considered from the top of the microscope to the bottom.
Optical microscopy was discovered in seventeenth century that started new era of investigation.
E. Abbe was the first to explain on the basis of diffraction effects that there is a limit to the smallness of the objects which might be produced by lens.
Approx. Cost: $4,000,000
A simple analogue
A better comparison
Basic Systems Making Up a Transmission
Electron Microscope
• The imaging system includes the objective, intermediate, and projector lenses that are involved in forming, focusing, and magnifying the image on the viewing screen as well as the camera that is used to record the image.
Vacuum
The electron microscope is built like a series of vessels connected by pipes and valves separate all the vessels from each other.
Why TEM?
The uniqueness of TEM is the ability to obtain morphological (grain size, grain boundary and interface, secondary phase and distribution, defects and their nature, etc.), crystallographic, atomic structural and microanalytical such as chemical composition (at nm scale), bonding (distance and angle), electronic structure, coordination number data from the sample. TEM is the most efficient and versatile technique for the characterization of materials.
Table. Electron properties as a function of accelerating voltage.
Accelerating voltage (kV) 100 120 200 300 400 1000
Wavelength (nm) 0.00370 0.00335 0.00251 0.00197 0.00164 0.00087