Vacuum Science World

Vacuum Science World is a centralised educational and information portal for all things relating to vacuum science, and a global community for those interested in or working in the vacuum technology industry.

Vacuum Science World has a repository of in-depth, high-quality content on vacuum technology – including thought leadership, articles and interviews, ranging from vacuum science and related applications, vacuum physics, vacuum generation, measurement and analysis to leak detection, practical information around vacuum systems and its installation, operation, control and maintenance.

The evolution of vacuum science which started in the 17th Century, has mirrored many other scientific achievements, including the the development of the Gas Laws and the discovery of the electron. Nevertheless, the world of vacuums still continues to excite and galvanise engineers and scientists. Indeed, ground breaking developments continue to push the boundaries of this fascinating subject.

Vacuum Physics - Basic Terms


What is the unit of Vacuum Pressure?

Below is an overview of the major pressure units and conversion of pressure units:

Pressure units and conversions


Vacuum Ranges

It is common in vacuum science to sub-divide pressure ranges into five individual regimes:

  • Rough (or Low) vacuum (R): Atmospheric to 1 mbar

  • Medium (or Fine) vacuum (MV): 1 to 10–3 mbar

  • High vacuum (HV): 10–3 to 10–7 mbar

  • Ultra-high vacuum (UHV): 10–7 to 10–12 mbar

  • Extreme High Vacuum (XHV): greater than 10-12 mbar. 

These divisions are somewhat arbitrary, with various engineering disciplines using their own definitions, ie chemists frequently refer to their spectrum of greatest interest (100 to 1 mbar), as an “intermediate vacuum”, whilst some engineers may refer to a vacuum as “low pressure” or “negative pressure”.