Improved S-2 Glass Fabric Insulation for $\hbox {Nb}_{3}\hbox {Sn}$ Rutherford Cable

A direct-braid fiberglass cloth insulation has been developed and evaluated for use on Rutherford cable. The fabric is directly woven onto the cable, using fine-filament yarn sized with a silane mixture. The total thickness of the cloth on each face of the cable is ~55 microns. The sizing is compatible with subsequent reaction heat treat without decomposition, and provides improved wetting and adhesion in the final epoxy impregnation. Ten-stack assemblies of cable segments have been processed through typical coil heat treatment and impregnation and tested for high-voltage insulation and yield strength under mechanical shear.