läpäisymikroskooppi

Lävpäisymikroskooppi, known in English as a transmission electron microscope (TEM), is a powerful microscopy technique that uses a beam of electrons to image a sample. Unlike a scanning electron microscope (SEM) which scans the surface of a sample, a TEM transmits a beam of electrons through an ultra-thin specimen. The electrons that pass through the sample are then magnified and focused onto an imaging device, such as a fluorescent screen or a digital camera.

The resolution of a TEM is significantly higher than that of light microscopes, allowing for the visualization of structures at the atomic level. This high resolution is due to the shorter wavelength of electrons compared to visible light. TEMs require samples to be very thin, typically on the order of tens to hundreds of nanometers, as the electrons must be able to pass through them. Sample preparation for TEM can be a complex and time-consuming process, often involving techniques like ultramicrotomy, fixation, and staining with heavy metals to increase contrast.

TEMs are used in a wide range of scientific and technological fields. They are indispensable tools in materials science for studying the microstructure of metals, ceramics, and polymers, as well as for analyzing defects and crystal structures. In biology, TEMs are used to examine the fine details of cells, organelles, viruses, and macromolecules. They are also employed in semiconductor research and development for inspecting integrated circuits. The ability of TEMs to provide detailed internal structural information makes them crucial for understanding the properties and behavior of materials and biological specimens.