Generation of magnetic fields over 20 T using a newly developed superconducting magnet system

In February 1992, a newly developed superconducting magnet system at the National Research Institute for Metals accomplished generation of a magnetic field of 20.3 T in its clear bore of 44 mm in diameter. The authors give an outline of the magnet system together with the operation results. The required time to cool down from 4.2 K to 1.8 K was about 4 h. The operations carried out at 1.8 K proved that saturated superfluid helium can be applied as coolant for large scale superconducting magnets because no problems, such as a discharge in the coils, were observed even when quenches occurred. This magnet system may be useful for testing coils of new high-field superconductors.<>