Effect of Cable Edge Deformation on RRR and Magnetization of Strands Extracted From ${\rm Nb}_{3}{\rm Sn}$ Rutherford-Type Cables

Modern high-J_c Nb₃Sn strands and cables used in high field accelerator magnet models suffer from flux jump-related instabilities at low magnetic fields, these instabilities are exacerbated by enhanced magnetization and/or reduced RRR. Such instabilities and their response to d_eff and RRR in individual strands have been widely reported. In this work, we look at the influence of strand deformation during cabling on RRR and magnetization for strands extracted from Nb₃Sn Rutherford cables. Seven separate cable types were used for this study, a number which had been previously used in both racetrack and quadrupole magnets. In the present experiments, longitudinal variations of RRR were estimated from multiple-tap measurements along the length of strands extracted from the various cables and then reacted in a special fixture. Magnetization measurements were then performed on cable sections to examine the effect of edge deformation. The implications of these measurements for stability are discussed.