The Compact Muon Solenoid (CMS) is one of the general-purpose detectors to be provided for the LHC project at CERN. The design filed of the CMS superconducting magnet is 4 T, the magnetic length is 12.5 m and the free bore is 6 m. Approximately 2000 km of superconducting strand is under procurement for the conductor of the CMS superconducting solenoid. Each strand length is required to be an integral multiple of 2.75 km. The strand is composed of copper-stabilized multifilamentary NbTi with Nb barrier. Individual strands are identified by distinctive patterns of NbTi filaments select4d during stacking of the monofilaments. The statistics of piece length, measurements of Ic, N-value, copper RRR, (Cu+Nb)/NbTi ratio, as well as the results of independent cross checks of these quantities, will be presented. An R&D study was performed on the CMS strands to investigate the critical current degradation due to various heat treatments. The degradation versus annealing temperature and duration are reported.
Citation: IEEE Transactions on Applied Superconductivity
Pub Type: Journals
critical current, interlaboratory comparison, n-value, Nb-Ti, piece length, residual resistivity ratio