What is difussion pump?

A diffusion pump is a vacuum pump used to create high vacuums by heating a vapor to obtain a low pressure. The pump's working principle is based on the diffusion of vapors, which occurs when the vapor jet enters a high vacuum and collides with gas molecules. The gas is compressed, and its partial pressure increases, forcing it to recirculate and be recaptured by the pump.

A diffusion pump typically consists of a heated source, a diffusion tube, a condenser, and a vacuum valve. During operation, the heated source vaporizes the working fluid (usually silicone oil), which fills the diffusion tube. The high-pressure vapor jet enters the lower-pressure main chamber and collides with gas molecules. As a result, gas molecules are pumped out of the chamber, creating a low-pressure environment.

Diffusion pumps are commonly used in applications where high vacuum is required, such as in semiconductor manufacturing, electron microscopy, space simulation, and mass spectrometry. The advantages of diffusion pumps are their high pumping speed, low cost, and low noise. However, they require careful maintenance, as the oil can get contaminated and needs to be changed regularly.