Simulation of the Fast Dump Process of the ATLAS toroids

by Gabriella Rolando (CERN)

Tuesday 26 May 2009, 08:00 → 09:00 Europe/Zurich

1/1-025 (CERN)

The ATLAS Detector magnet system comprises three superconducting toroids: a Barrel Toroid and two End Cap toroids. Each toroid is built up from 8 racetrack coils wounded with an Al stabilized Nb-Ti Rutherford cable, conduction cooled at 4.5 K through two-phase helium circulating in cooling lines attached to the cold masses. The three toroids are operated in series at 20.5 kA with a total stored energy of 1.6 MJ. A key requirement in the magnet design is the safe fast dump process of the system in the case of a quench. In order to verify the reliability of the protection system, series of fast dump tests have been performed on the single toroids as well as on the entire toroid system. A model to simulate the fast dump of the ATLAS toroids in single and three-toroids mode was developed and validated through systematic comparison with measured run-down data concerning quench current, quench voltages across the various coils and local cold mass temperatures. The characterization of the fast discharge is completed by the determination of the energy dissipation in the various coils and dump unit. The model and the main characteristics of the fast dump process in these very large toroids will be presented.

Slides presentazione_CERN3.pdf presentazione_CERN3.ppt