What Is the Use of Tungsten Wire in Electron Microscopes?

The application of tungsten wire in Electron Microscope (EM) mainly focuses on two key areas: hot cathode of electron microscope and electron beam sampling.

Hot Cathode for Electron Microscopes: Electron microscopes require a highly stable electron source to generate the electron beam used to image the sample. Tungsten wire is often used as a hot cathode in electron microscopes because it has the following characteristics:

High Melting Point: Tungsten wire’s high melting point (approximately 3,422 degrees Celsius or 6,192 degrees Fahrenheit) enables it to stably generate electrons at high temperatures.

Stability: Tungsten filaments maintain the stability of electron production over long periods of time, which is critical for obtaining clear microscope images.

Long life: Tungsten cathodes generally have a long service life, which can reduce maintenance costs.

The tungsten filament cathode is heated to generate electrons, which are focused into an electron beam and then used to scan the sample to obtain high-resolution microscopic images.

Electron Beam Sampling: In addition to hot cathodes as electron sources, tungsten wires can also be used in Electron Beam Micromachining applications. In this case, the electron beam can be precisely machined, engraved or cut by focusing on the sample surface. This is useful in materials research and micromachining because the electron beam has high energy and fine control.