Critical Current and Stability of High-${\rm J}_{\rm c}$${\rm Nb}_{3}{\rm Sn}$ Rutherford Cables for Accelerator Magnets

Abstract

In the framework of future LHC upgrades using Nb3Sn magnets, supported in part by the US LHC Accelerator Research Program (LARP) and the European EuCARD program, CERN is intensifying its research on Nb3Sn Rutherford cables. In the FRESCA cable test facility at CERN, two new Nb3Sn cable samples were investigated concerning their quench and critical current as well as stability performance. The two samples are based on RRP type strands with comparable layout. They have 27 strands with 0.7 mm diameter while the strands have 54 or 108 superconducting sub-elements. The cables are 10 mm wide and have a transposition pitch of about 75 mm. The cables are used in magnets built for LARP. Their performance is measured as a function of magnetic field up to 10 T with ramp rates of 10 to 1000 A/s and temperature of 1.9 and 4.3 K. A hall probe array is present to study the current distribution. Point heaters are used to study cable stability and current redistribution.