Compressive strain and critical current properties of Nb3Sn conductors reinforced by center-arranged and distributed Ta

We have fabricated two kinds of Nb₃Sn superconductors having the same diameter; one superconductor is reinforced by center-gathered tantalum (Ta) in a cross-section of the conductor, and the other is reinforced by distributed Ta in the cross-section. We applied compressive force to the conductors, and measured degradation of the conductors. When the conductor´s strain due to the compressive force to the conductors was zero, a critical current (I_c) of the distributed Ta conductor was larger than that of the center-gathered Ta conductor. However, an I_c of the distributed-Ta type conductor rapidly decreased, and when the compressive strain became approximately 5 or 6%, the I_c of the center-gathered Ta conductor exceeded that of the distributed-Ta type. It was experimentally shown that the center-gathered Ta conductor was more tolerant than the distributed Ta conductor about the compressive strain to the conductor.