Design and Manufacture of a Test Cryostat With MgB2 Superconducting Magnet Significantly Reducing Helium Consumption

A test cryostat equipped with a conduction-cooled MgB
₂
high-temperature superconducting bias magnet has been designed, manufactured, and demonstrated. This cryostat is more environmental-friendly and user-friendly than the conventional cryostat with an immersion-cooled NbTi superconducting magnet. Liquid helium consumption is reduced by almost half of that of a previous conventional cryostat because the MgB
₂
magnet does not need liquid helium for cooling itself. A ramp-up rate of the bias magnet has also been improved to 1 A/s, which is almost 10 times faster than that of the previous NbTi magnet, due to the high stability of the superconducting MgB
₂
magnet. A maximum bias magnetic field is 1 T at the center of the magnet. A helium vessel of the cryostat is 212 mm in inner diameter so that various superconducting samples such as bulks, short samples of wires, and small coils, could be immersion-cooled by cryogen and tested in it. A performance demonstration was also successfully conducted.