A novel current calibration system up to 20 kA

The Large Hadron Collider (LHC) particle accelerator project will require an accuracy of a few parts in 10^6 in the control of the current to the superconducting magnets. A new infrastructure for calibration is being built at CERN based on DC current reference standards rather than voltage. The paper describes the rationale, the infrastructure, the transfer methods, and the performance.