The Brookhaven muon storage ring magnet

Their "nal result: was a "11659230(84);10\. Abstract The muon g-2 experiment at Brookhaven National Laboratory has the goal of determining the muon anomalous g-value a ("(g!2)/2) to the very high precision of 0.35 parts per million and thus requires a storage ring magnet with great stability and homogeniety. A superferric storage ring with a radius of 7.11 m and a magnetic "eld of 1.45 T has been constructed in which the "eld quality is largely determined by the iron, and the excitation is provided by superconducting coils operating at a current of 5200 A. The storage ring has been constructed with maximum attention to azimuthal symmetry and to tight mechanical tolerances and with many features to allow obtaining a homogenous magnetic "eld. The fabrication of the storage ring, its cryogenics and quench protection systems, and its initial testing and operation are described