ATLAS End Cap Toroid Integration and Test

The ATLAS Experiment at LHC, CERN will utilize a large, superconducting, air-cored toroidal magnet system with a long Barrel Toroid and two end cap toroids. Each end cap toroid will contain eight racetrack coils mounted as a single cold mass in a cryostat vessel of approximately 10 m diameter and 5 m width. The toroids provide the magnetic field for the muon detectors. The operating current is 20.5 kA at 0.25 GJ stored energy and a peak field of 4.1 T in the windings. This paper presents the status of the End Cap Toroid Project. Cold mass assembly and the integration of the full cold mass, 120 tons, into the vacuum cryostat for the first toroid are described. The specialized techniques, procedures and tooling infrastructure required for these operations are explained. The pre-installation cooldown to 77 K at the ATLAS cryogenic test facility is reported and the toroid installation in the ATLAS Experiment 100 m underground in the ATLAS cavern will be reviewed.