Low Temperature Superconducting Magnet Connected to a Cryocooler by Conductive Link

A low-temperature superconducting (LTS) magnet cooled by a cryocooler has been designed, fabricated, and tested for lab-scale material control device. The superconducting magnet incorporates a solenoidal configuration with a copper former which has a 52-mm room-temperature bore. The superconducting coil is installed in a cryostat maintaining high vacuum and is cooled by a two-stage cryocooler. In order to maintain the operating temperature of magnet at the designed level, the cold head temperature of a cryocooler must be lower so that heat can be removed from the superconducting coil. Also, a temperature difference occurs between the magnet and cryocooler and its magnitude is dependent upon the contact resistance at the interface between the metals in the conductive link. The performance of the LTS magnet is investigated with respect to the conductive link between the magnet former and the cold head of a cryocooler. In addition, the effects of the contact pressure and interfacial materials on the temperature distribution along the conductive link are discussed.