System and method for maintaining vacuum in superconducting magnet system in event of loss of cooling

An apparatus, comprising:

• a vacuum chamber having one or more walls enclosing an interior space of the vacuum chamber;
• a heat shield disposed within the vacuum chamber, the heat shield defining an inner region of the vacuum chamber within the heat shield and an outer region of the vacuum chamber disposed between the heat shield and the one or more walls of the vacuum chamber;
• a superconducting magnet disposed within the inner region of the vacuum chamber;
• a cryocooler configured to cool the superconducting magnet, the cryocooler
• providing at least one cold station within the inner region of the vacuum chamber;
• a getter material disposed within the inner region of the vacuum chamber and which is configured to absorb stray molecules within the vacuum chamber;
• a thermal mass disposed adjacent the getter material and in thermal communication with the getter material, wherein the thermal mass is disposed at a lower greater than a height at which the at least one cold station is disposed;
• and
• a convective cooling loop connected between the thermal mass and the cold station and configured to convectively cool the thermal mass when the cold station is at a lower temperature than the thermal mass, and to substantially thermally isolate the thermal mass from the cold station is at a higher temperature than the thermal mass.

A method, comprising:

• providing within a vacuum chamber a thermal mass adjacent to a getter material and in thermal communication with the getter material to absorb heat from the getter material;
• cooling the thermal mass with a cold station disposed within the vacuum chamber at a height greater than a height at which the thermal mass is disposed, in turn cooling the getter material, wherein the cooling is performed via a convective cooling loop connected between the thermal mass and the cold station;
• and
• absorbing stray molecules within the vacuum chamber with the cooled getter material,
• wherein the convective cooling loop substantially thermally isolates the thermal mass from the cold station when the cold station is at a higher temperature than the thermal mass.