6. Miscellaneous equipment

6.1 Introductory airlock

It is often necessary to introduce one or more objects under vacuum, without having to return to atmospheric pressure and repump the enclosure. For this purpose, an airlock is used, comprising an auxiliary volume connected to the chamber by a valve, which can be pumped independently.

When the parts to be introduced are small, the airlock flanges are circular. When part dimensions exceed 150 or 200 mm, rectangular flanges are used. American module manufacturers for MBE (Molecular Beam Epitaxy) systems, used in the manufacture of semiconductors and other products, have agreed on certain dimensions. The result is an (unofficial) standard for rectangular flanges suitable for this application: the SEMI-MESC standard.