Quench location in the superconducting model magnets for the LHC by means of pick-up coils

High field superconducting dipole magnets were manufactured in industry or at CERN as model magnets for the future Large Hadron Collider (LHC) particle accelerator and tested in superfluid helium. The pick-up coil method is now in use to precisely locate the origin of training quenches and to monitor the propagation of the transition. The improvements made on this diagnostic method is reviewed. This experience allows the location of the onset of the quenches both axially and in the cross section of the winding even for magnets equipped with a minimum of voltage taps on the winding. The location of training quenches are now understood to be related to the structure of the superconducting coil.<>