Superconducting magnetic system of the detector KEDR

The detector KEDR will be used in high-energy physics experiments on the storage ring VEPP-4M. The authors describe the KEDR magnetic system, which consists of a main superconducting coil, compensating superconducting solenoids, and an iron yoke closing the magnetic flux. The main superconducting coil is a one-layer solenoid of 3-m diameter and 3-m length with an inductance of 1.2 H, an effective field of 2 T, and a stored energy of 42 MJ. The superconducting coil is wound around and soldered to the inner surface of a ringlike helium vessel and is cooled indirectly through a 10-mm stainless steel wall of the vessel. A superconducting flux pump supplies the coil with 8-kA current. The iron yoke provides the required uniformity of the field. The compensating superconducting solenoids have a length of 450 mm, a diameter of 120 mm, and a magnetic field of 6.7 T. The total weight of KEDR is approximately 1000 tons