Abstract: A helium cooled superconducting magnet assembly with helium gas recondensing apparatus to return liquid helium to the helium supply in the helium vessel in which the recondensing apparatus positioned within the space between the vacuum vessel and surrounding vacuum vessel in thermal contact with a cryocooler within a fixed cryocooler sleeve in the vacuum vessel with the cryocooler positioned to minimize magnetic disturbances to the magnet assembly magnetic field and the recondenser connected through thin corrugated steel tubing to the helium vessel with the tubing sized to provide thermal and vibration isolation of the helium vessel.

Abstract: A helium cooled superconducting magnet assembly including helium gas recondensing apparatus to return liquid helium to the helium supply in the helium vessel includes a recondenser positioned in the helium vessel above the helium supply connected to a cryocooler in a dual-sleeve assembly enabling breaking of thermal joints with thermal isolation from the helium for servicing of the cryocooler during superconducting operation of the magnet assembly, and providing recondensing of helium gas to fall by gravity back to the helium supply.

Abstract: Apparatus for reducing heat leakage into the interior of a liquid cryogen-holding vessel from the sealed well through which the vessel is accessed. An actively cooled heat sink in the well transfers heat to low temperature cryogen vapor venting from this vessel to the external environment.