The protection system of the superconducting coil of the barrel toroid of ATLAS

An analysis of the discharge of the Barrel Toroid under several operating conditions has been carried out. The main critical parameters of the discharge (i.e. the maximum temperature inside the coils, the maximum temperature gradient, the maximum voltage at the coil ends and the maximum decentering forces acting on the BT and ECT magnets) have been calculated for several operating conditions (heaters on, heaters off, short circuit with heaters on or off). The aim of this analysis is to provide a cross check of the protection design of the Barrel Toroid coils with an independent study. The results validate the choice to use a low value of dump resistance, and give some important warning in the case of heater failure or presence of a short circuit.