What is a Transmission electron microscope / Transmission microscope?

Transmission Electron Microscopy (TEM) is a device that transmits an electron beam through a sample and obtains an image based on the attenuation of the transmitted electrons. The principles and characteristics of TEM are explained below.

principle
Generation and acceleration of electron beam: Electrons are generated from an electron gun by applying a high voltage (usually around 300kV from several tens of kV). This accelerates the electron beam. Transmission of the sample: An accelerated electron beam is applied to a very thin sample. When an electron beam passes through a sample, attenuation and scattering occur depending on the structure and components of the sample.

Image formation: The transmitted electron beam has different intensity depending on the thickness and density of the sample. This is detected using a fluorescent screen or camera and displayed as an image.

Features
High resolution: The resolution of TEM is extremely high, making it possible to observe fine structures at the atomic level. When using an accelerating voltage of 300 kV, the electron wavelength is approximately 0.00197 nm, and the resolution reaches 0.1 nm.
High magnification: TEM allows observation at very high magnification. The maximum magnification is 800,000 times, which is about 800 times that of an optical microscope.

Observation of internal structure: TEM uses electrons that have passed through the sample to obtain images, so it is suitable for observing the internal structure of a sample in detail. It is especially used to study crystal structures and nanoscale microstructures.
Thinness of the sample: In order to transmit the sample, the thickness of the sample must be adjusted to be very thin. It is usually sliced to a thickness of several tens of nanometers.

TEM is used in many fields such as materials science, biology, physics, and chemistry. Specific examples include:

Materials science: Analysis of crystal structures of metals, ceramics, etc.
Biology: Observing the internal structure of cells and viruses
Nanotechnology: Analysis of morphology and structure of nanomaterials
Chemistry: Research on catalyst nanostructures and reaction mechanisms

TEM has high resolution and the ability to observe detailed internal structures, and plays an important role in many scientific and technological fields.

Application of Transmission electron microscope / Transmission microscope

By using a transmission electron microscope, the internal structure of the sample can be observed at a magnification of several hundred times to several million times. In other words, it can cover from the observation of the whole cell at the level of several tens of μm to the observation of the atomic arrangement structure at the level of several Å (1 Å (angstrom) = 10 minus 10 meters). Transmission electron microscopes can be used for observing various objects such as structural analysis of various materials such as semiconductors and ceramics, and structural analysis of biological samples such as cells and bacteria. In addition, it is possible to observe electron diffraction patterns by adjusting the lens system, perform elemental analysis and state analysis by additionally installing a spectroscopic device, and acquire various information.

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