Search of short circuits in the superconducting coils of the ATLAS detector

The detection of a short circuit inside the superconducting coils of the ATLAS detector after their installation in the casing is mandatory for the mechanical and electrical safety during a fast discharge of the magnet. The detection of a short circuit by means of a capacitor discharge becomes very difficult once the coils are integrated inside the casing, which behaves as a short-circuited turn strongly coupled with the coils. Under these circumstances a preliminary and careful analysis of the electrical parameters of the electrically coupled system and of the discharge behavior is required in order to clearly detect a short circuit. The paper presents and discusses the results of the analysis and the measurements carried out on the 16 double pancakes of the ATLAS Barrel Toroid after their integration inside the casing.