The coil winding for the central solenoid magnet of the forthcoming ATLAS experiment at CERN's Large Hadron Collider has been completed. It will provide a magnetic field of 2 T at the centre of ATLAS's tracking volume. This superconducting solenoid was designed and developed by Akira Yamamoto and his team at the Japanese KEK Laboratory, as Japan's contribution to the ATLAS magnet system. The project is led by Takahiko Kondo.

Weighing in at 5.5 tons, the coil is 2513 mm in diameter, 5300 mm long and 45 mm thick. Conductors made of high-strength aluminium stabilizer, developed by Furukawa Electric and Hitachi Cables, have been used so that the coil is as thin as possible. Some 8.92 km of conductor is coiled into 1151 turns inside an aluminium cylinder, which was made by Oxford Instruments. The coil winding and curing was carried out by Toshiba in Japan and took four months.

Outer reinforcement rings currently support the solenoid. The rings will be removed early next year when the solenoid is incorporated into the inner cylinder of the cryostat, which is being constructed by the US Brookhaven National Laboratory, where the ATLAS liquid argon barrel calorimeter will be housed. The entire solenoid system will then undergo cooling and excitation tests in Japan before being shipped to CERN along with its associated cryogenics in 2001.