Small-size hermetic helium 3 refrigeration stage

摘要

The invention provides a small-size hermetic refrigeration stage containing helium 3 and easily incorporated in a conventional helium 4 metal cryostat. The stage consists essentially of a metallic enclosure containing a certain volume of helium 3 and having a first receptacle constituting the pumping chamber and consisting a mass of an adsorbing body for the helium 3 at a very low temperature, a second receptacle constituting a condenser for the cooled helium 3 and a duct. The stage of the invention is particularly suited for maintaining the sensitive element of an infrared detector at a temperature of less than 1 DEG K.