Engineering status of the superconducting end cap toroid magnets for the ATLAS experiment at LHC

The ATLAS experiment at LHC, CERN will utilise a large, superconducting, ai r-cored toroid magnet system for precision muon measurements. The magnet sy stem will consist of a long barrel and two end-cap toroids. Each end-cap to roid will contain eight racetrack coils mounted as a single cold mass in cr yostat vessel of similar to 10m diameter. The project has now moved from th e design/specification stage into the fabrication phase. This paper present s the engineering status of the cold masses and vacuum vessels that are und er fabrication in industry. Final designs of cold mass supports, cryogenic systems and control/protection systems are presented. Planning for toroid i ntegration, test and installation is described.