STABILITIES OF THE RUTHERFORD CABLES WITH CU MATRIX AND CUMN BARRIER

Superconducting coils for high energy accelerator magnets are usually fixed with epoxy resin in the fabrication processes called ''curing''. The assembled magnets in the processes have shown different critical current degradation figures due to excitation ramp rate even if they were made in the same manner. The ramp rate dependences of degradation seem to be affected by AC losses between strands of the Rutherford cables (inter-strand AC losses), which are easily affected by the curing conditions, Although they can be reduced by increasing cross-over resistances between strands, the stability problems caused by current sharing between strands may be arisen. It is important for such kind of superconducting accelerator magnets to clarify the mechanisms of the AC losses and stabilities of the Rutherford cables, Experimental studies on the AC losses and the current sharing problems for several types of cable samples have been performed.