A vacuum chamber
is a rigid enclosure from which air and other gases are removed by a vacuum pump
. The resulting low pressure, commonly referred to as a vacuum
, allows researchers to conduct physical experiments or to test mechanical devices which must operate in outer space
(for example). Chambers made of aluminum
allow one to control the magnetic field
inside from outside the vacuum. At the opposite chambers made of mu-metal
prevent external fields from entering the vacuum.
Chambers often have multiple ports, covered with vacuum flanges, to allow instruments or windows to be installed in the walls of the chamber. In low to medium-vacuum applications, these are sealed with rubber o-rings. In higher vacuum applications, the flanges have hardened steel knives welded onto them, which cut into a copper gasket when the flange is bolted on.