a thermostat that operates at very low temperatures.

an apparatus for maintaining a constant low temperature (as by means of liquid helium). Requires vacuum chambers to help with thermal isolation -- Dewar.

A vessel designed to keep its contents at a low (cryogenic) temperature. The outer can is hermeticly sealed, to maintain a vacuum inside. Because of the lack of air, heat flow into the cryostat by conduction is eliminated. Heat may still enter by radiation, so the contents are surrounded by reflective radiation shields, at intermediate temperatures. Also known as a Dewar, after its inventor.

a microtome (mechanical knife) used for sectioning frozen tissues