Superconducting magnet systems for the muon-electron conversion experiment

The Muon-to-Electron Conversion Experiment (MECO) seeks to detect muon to electron conversion, providing evidence that the conservation of muon and electron type lepton number can be violated. Observation of this violation would suggest physics beyond the Standard Model. The experiment is to be installed at Brookhaven National Laboratory (BNL). A high energy proton beam produces pions upon hitting a heavy target inside the 1.5 m diameter by 5 m long Production Solenoid (PS). A fraction of the muons from pion decay are captured in the 0.5 m diameter bore by the 13 m long, S-shaped Transport Solenoid (TS), which contains collimators, providing sign and momentum selection. The muons are stopped in a target inside a 1.9 m bore by 10 m long Detector Solenoid (DS) that houses detectors to measure the energy of the conversion electrons. Magnetic field is controlled to 5 T ±5% at the high-field end of the PS and to 1 T ±0.2% in the detector region of the DS. The conceptual design for the magnets is summarized, including conductor, coil, structure and cryogenic design.