Electro-Topological Analysis and Diagnostics of LHC Superconducting Magnets

by Piotr Komorowski (CERN/LHC)

Thursday 21 Oct 1999, 14:15 → 16:30 Europe/Zurich

CERN

The presentation addresses the design and implementation of diagnostic systems capable of detecting and localising possible electrical faults in the superconducting coils and in the instrumentation circuits of the LHC magnets. Two different techniques are discussed on the examples of practical cases encountered in the LHC String and in dipole model magnets. The first method is based on the measurement and analysis of the transient magnetic field generated inside the aperture of the magnet by a pulsed discharge. It allows both the longitudinal and azimuthal position of the fault-affected area (e.g. a possible inter-turn short-circuit) to be identified in the fully assembled magnet system with a precision of a few millimetres. The possible electrical failures encountered in the instrumentation circuits of the magnets (e.g. voltage tap, temperature, and pressure transducer circuits) are analysed with the second technique based on the standard Time Domain Reflectometry (TDR) methods. This approach involves the excitation of the circuit under test with either a fast edge step function or a well-defined impulse and thereafter detection of the amplitude and time of reflections.