Performance of a large superconducting spectrometer magnet-SKS

A sector-type superconducting spectrometer magnet, called SKS, for nuclear physics experiments in the 1-GeV/c region has been constructed and installed at KEK. It has a maximum central magnetic field of 3 T in a magnet gap of 50 cm, required by properties of high resolution and large acceptance. From another requirement to be movable around a target at a cold state, a flexible transfer line is adopted. The maximum rated current of 500 A is selected to make the heat losses as as small as possible. A small refrigerator is used for thermal insulations at 80 and 20 K in combination with a medium one at 4 K.<>