Transient stability of LHC strands

The Large Hadron Collider (LHC) machine will operate at 1.9 K in order to achieve the high bending fields required in the dipole magnets. The cable and coil matrix is designed to be 'porous' in order to allow the He II coolant to penetrate within the cable for stability enhancement. This paper describes transient stability measurements and theoretical modelling carried out on single strands from the LHC cable. The experimental work has been carried out at the Rutherford Appleton Laboratory under an agreement with CERN. The aim of the experimental work has been to measure the influence of the strand surface treatment on the quench energy. The surface treatment, oxidized copper, tin-silver, nickel etc., determines the transient heat transfer coefficients to the He II under high heat flux, short timescale (approximately 20 microseconds) conditions. The test equipment, based on an inductive heating technique, is described and quench energy measurements presented. The experimental results are compared with theoretical models developed at CERN and RAL in order to derive the heat transfer coefficients.