Multi-cylinder quadrupoles with square cross section

Compact superconducting quadrupole magnets with a total length of 150 mm, an integrated gradient of about 13 T, and good field quality are needed for the High Current Transport Experiment (HCX) at Lawrence Berkeley National Laboratory. The Advanced Magnet Lab, Inc. has developed a novel concept, called multi-cylinder coils, which is ideally suited for this application. In this concept a round mini-cable is placed in grooves, which are precisely machined in flat support plates. The plates are stacked on top of each other to build up multilayer coils. The grooves guarantee precise placement of the conductor with high design flexibility, giving unique control over random and systematic field errors and management of mechanical stress. The designed quadrupole consists of four subcoils, which form the four sides of a square cross section box. Each subcoil is built up from 6 plates, accommodating 6 layers of conductor. The complete quadrupole is wound from a continuous conductor with no internal splices. Test results from the first prototype magnet are presented