Strand critical current degradation in Nb3Sn Rutherford cables

Fermilab is developing 11 Tesla superconducting accelerator magnets based o n nb(3)Sn superconductor, Multifilamentary Nb3Sn strands produced using the Modified Jelly Roil, Internal Tin, and powder-in-Tube technologies were us ed for the development and test of the prototype cable. To optimize the cab le geometry with respect to the critical current, short samples of Rutherfo rd cable with packing factors In the 85 to 95% range were fabricated and st udied. In this paper, the results of measurements of critical current, n-va lue and RRR made on the round virgin strands and on the strands extracted f rom the cable samples are presented.