Characterization of NbTi wires for the electron-ion collider project

Abstract The Electron-Ion Collider (EIC) is a proposed particle accelerator to explore the behaviour of the fundamental particles and forces that bind atomic nuclei together. EIC will use several different types of superconducting strands for magnets near the interaction region (IR). In low magnetic fields at beam injection, considerable field errors are generated from magnetization currents in the superconducting strands even having very fine filaments. The accurate magnetization measurement results from those superconducting strands will be critical for the calculation and future correction of magnetic fields for EIC. In this work, we characterized three different superconductor NbTi wires. The magnetization was measured at 4.2 K and 1.9 K in magnetic fields below 1.5 T. The critical current at 4.2 K and in magnetic field down to 5 T were also measured. Other properties that are important for the safety margin of superconducting magnet such as residual-resistance-ratio (RRR), filament diameter, Cu to non-Cu ratio, twist pitch, and mechanical properties at 77 K are also presented.