Data Acquisition System for Large Superconducting Magnets

Data acquisition systems play an important role in any scientific apparatus. Furthermore, large magnets need to operate in large and industrial environment with many noise sources (power supplies and lines, cryogenic plants, cranes, etc.). In addition the size itself of the magnet can increase the noise problems, because of the inductive coupling with the coil. In this paper the LASA data acquisition system for the ATLAS Barrel Toroid test station is described. The problems encountered during the design, realization and commissioning of the system are discussed. In particular the LASA laboratory, after the tests on two insulation cards developed at CERN for LHC, has designed a new circuit which fits better the needs of BT data acquisition requirements. The h/w and s/w solutions to reduce common mode voltage, ground loops, electromagnetic noise and to protect the electronics from quench overvoltages are presented. Validation of the system is provided by the tests performed on the magnet models (B00 and B0) and on the final Barrel Toroids