High accuracy current measurement in the main power converters of the large hadron collider: tutorial 53

In the Large Hadron Collider (LHC) at CERN, the powering of the main dipole and quadrupole circuits is divided into eight separate powering sub sectors due to the very high magnetic energy stored in these circuits and to protection constraints of the superconducting magnets [1]. As a consequence, individual sector currents must be controlled with very high accuracy in amplitude and time to ensure that the beam of particles sees the same magnetic field in all sectors. This results in a requirement for current tracking between the different sectors of better than ± 5 ppm and short term stability of better than ± 2 ppm [1], at 13 kA currents.