Thin and compensating solenoids for ZEUS detector

A thin solenoid and a compensating solenoid which will be installed in the ZEUS detector at the Hadron Electron Ring Accelerator collider are described. The thin solenoid of 1.88-m diameter, 2.5 m in length, is characterized by a high magnetic-field level (B=1.8 T), two-layer winding and variable linear current density. The improvements on the general design, the cable design, and measurements on the prototype cable are reported and discussed in detail. The solenoid, wound in two layers of Al-stabilized NbTi/Cu superconductor, will operate at 5000 A. Indirect cooling through the external restraining cylinder will ensure an operating temperature lower than 4.5 K. The required field homogeneity will be achieved by grading the current linear density along the solenoid axis instead of using end correction coils.