The Magnetization of Bi:2212 Rutherford Cables for Particle Accelerator Applications

High temperature superconductors, including Bi:2212, are being considered for high magnetic field magnets to be used in particle accelerators. Aknowledge of HTS magnetization properties are needed for calculating field errors in such accelerator magnets. Here we present magnetic measurements of a 17 strand Bi:2212 Rutherford cable. The Bi:2212 strand was a Bruker OST PMM170123 non-twisted wire wound into a cable with dimensions 1.46 mm x 7.8 mm and cable pitch of 50.8 mm. M-H loop measurements were made with a Hall probe at 4.2 K. Two calibration methods were compared, (i) a flux exclusion approach, and (ii) a Ni replacement technique. The latter was found to be more reliable in this case. An effective filament diameter of 358 mu m was calculated for the strand at 4.2 K and a perpendicular applied field of 3.33 T, significantly larger than the diameter of the filament bundle. Magnetization values at 1 T on the shielding branch were seen to be 100 kA/m when normalized to the total strand in the cable volume. The penetration field congruent to 0.4 T.

Automated summary

In this study, magnetic measurements were conducted on a 17-strand Bi:2212 Rutherford cable using a Ni replacement calibration method, resulting in the calculation of an effective filament diameter and observation of magnetization values at 1 T on the shielding branch.