The ATLAS superconducting magnet system at the Large Hadron Collider

A magnet system of three superconducting toroids and a solenoid with record overall system dimensions of 25 m in length and 22 m in diameter, generate the magnetic field for particle bending in, respectively, the muon and inner detectors in the ATLAS experiment at the Large Hadron Collider. The magnet technology is based on aluminum stabilized NbTi superconducting cables wound into impregnated windings which are conduction cooled and operate at 4.6 K. Magnetic field is generated in the usable detector area of about 12000 m³ and the peak field in the coil windings is 4.1 T. The magnet system stored energy is 1.6 GJ. After successful on-surface tests the magnets were installed in the ATLAS cavern 100 m underground. The Barrel Toroid and Solenoid were charged to full field in autumn 2006 while both End Cap Toroids are powered in November 2007 thereby completing this very challenging and largest magnet system successfully constructed so far