Effect of Core Width, Placement, and Condition on Calorimetrically Measured AC Loss and Interstrand Contact Resistance of Stainless-Steel-Cored $\hbox{Nb}_{3}\hbox{Sn}$ Rutherford Cables

Abstract

Calorimetric measurements of AC loss were made on Nb3Sn Rutherford cables furnished with cores of widths 4.5, 5.2, and 10.8 mm in the face-on (FO) and edge-on (EO) orientations of the applied AC field. The resulting FO-measured effective interstrand contact resistances, Rperp,e,f,f., were compared with that of the uncored cable after which it was noted that although the uncored Rperp,e,f,f. agreed well with those of previously measured cables, the cored values -0.3 to 8 muOmega were lower than expectation. The relatively low -Rperp,e,f,f. s are attributed to (i) drifting of the narrower cores to one edge of the cable (ii) shrinkage of the effective width of the widest core as a result of severe texturization. After correcting for these deficiencies the projected Rperp,e,f,f. for the widest-core cable moved closer to the range of values expected for a full-width-core Nb3Sn cable.