Stability and quench propagation velocities measurements on the ´racetrack´ mock-up of ATLAS toroid coil

A mock-up of ATLAS toroid coil, which is one of the 3 detectors presently under construction for the future Large Hadron Collider at CERN, had been tested at Saclay. Various experiments have been led to check the validity of important technical options for the magnet. This paper focuses on thermal stability and quench propagation velocities measurements. For a 70/spl times/7 mm/sup 2/ aluminum-stabilized conductor carrying a 20 kA current, a 4-5 joule minimum quench energy and a 20 m/s longitudinal quench propagation velocity were found. We also studied the dependence of those features according to the operating current in the 5-20 kA range.