Current distribution in a reusable junction for W7-X coil tests

In the frame of the W7-X stellarator project, CEA has to perform the acceptance tests of the 70 superconducting coils of the magnet system. A new test facility has been built at Saclay for that purpose. As the coils are delivered to CEA with bare end, it has been necessary to develop a junction that can be easily applied on a CIC conductor and that can be easily dismantled and reusable due to the large number of coils to be tested. As inhomogeneous current distribution within the conductor could lead to unexpected low quench current (i.e., ramp rate limitation), an experiment has been developed in order to estimate that distribution at the outlet of the junction. The experimental set-up is made of 16 pick-up coils measuring the current within the 16 sub-stages of the CIC (Cable-In-Conduit). This paper will present our experimental results and the conclusion of our analysis.