Scan measurements on ROEBEL assembled coated conductors (RACC)

The application of RE-BCO coated conductors (cc's) in high field magnets as well as in electrical machinery decisively depends on the ability to produce conductors with high current densities and small losses. The production process of the conductors restricts the thickness of the superconducting layer and therefore the current. It is possible to enhance the current carrying capability by combining several conductors to a cable. The ROEBEL bar concept is the most suitable solution because of reduced ac losses. Cc's are suitable for shaping ROEBEL strands and to perform the cabling. We employed different scan techniques to get an overview of the conductor properties. The magnetoscan, which was successfully applied to cc's, was optimised for scanning a prototype of such a RACC-cable. The resulting map of the magnetic field reflects the superconducting properties of the conductor and allows analysing the defect structure and the critical currents. Due to the complex configuration of the RACC-cable some considerations concerning the effects at conductor edges and the transitions between the strands were necessary. The field map of the ROEBEL-cables can be used to optimise them.