Analysis of the AC loss measurements on the one-metre dipole model magnets for the CERN LHC

Superconducting single- and twin-aperture dipole model magnets for the future CERN Large Hadron Collider have been built in industry and tested at CERN. In this paper the results of AC loss measurements are presented that are performed on 6 magnets all having a bore of 50 mm diameter and coils wound of 17 mm wide superconducting cables. The cables that are used in these models differ with respect to the filament diameter, the strand coating and the fact whether the cable is (partially) soldered or not. The energy loss, determined electrically as the difference between the stored energy and the extracted energy during a current cycle, consists mainly of filament hysteresis and inter-strand coupling loss. The hysteresis component is in fair agreement with calculations. The inter-strand coupling loss varies with about a factor 5 between the models due to a different contact resistance between crossing strands in the cable (varying in the range from 1 to 10 /spl mu//spl Omega/). Even for model magnets which are made with the same cable the inter-strand coupling loss can differ significantly.<
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