Self-triggering cryogenic heat flow switch

In a cryogenic cooling arrangement including a selectively actuatable heat sink, an end use application which is to be cooled, and a cryogenic heat flow switch selectively coupling said end use application with said heat sink for heat transfer therebetween, an improvement wherein said switch is a

• self-triggering cryogenic heat flow switch comprising an outer hollow cylinder that has an inner perimeter surface and that is connected to said heat sink, an inner body that has an outer perimeter surface arranged coaxially relative to and at least partly within said inner perimeter surface of said outer hollow cylinder and that is connected to said end use application which is to be cooled, and a plurality of spacers arranged radially between said outer perimeter surface of said inner body and said inner perimeter surface of said outer hollow cylinder,
• wherein said outer hollow cylinder has a first linear thermal expansion coefficient, and said inner body has a second linear thermal expansion coefficient that is less than said first linear thermal expansion coefficient, and
• wherein a concentric annular gap is formed between said outer perimeter surface of said inner body and said inner perimeter surface of said outer hollow cylinder and is maintained by said spacers when said heat sink is not actuated, and said concentric annular gap is closed and said inner perimeter surface of said outer hollow cylinder comes into contact with said outer perimeter surface of said inner body when said heat sink is actuated.