Minimum Quench Energy measurements on single strands for LHC main magnets

3The stability of magnet conductors can be characterized by their Minimum Q uench Energies (MQE), i.e. the minimum energy pulse of small extent and sho rt duration needed to initiate a quench. The MQE of a considerable number o f prototype strands for the superconducting LHC magnets have been measured at BNL within the framework of the US-CERN accelerator collaboration. The m ain interest of this work was to study the effect of different strand desig ns, copper to superconductor ratios (Cu/Sc) and the source of the niobium-t itanium alloy on MQE. Although MQE varied significantly between the strands , the measurements revealed that except for Cu/Sc ratio, these above stated parameters do not affect MQE in a consistent way. Numerical simulations in dicate, that these tests made with a restricted helium volume and heat exch ange surface were quasi-adiabatic in nature, and hence the influence of the cooling even in superfluid helium was minimal.