Progress in Wind-and-React Bi-2212 Accelerator Magnet Technology

We report on our progress in the development of the technology for the application of Bi₂Sr₂CaCu₂O_8+x(Bi-2212) in Wind-and-React accelerator magnets. A series of superconducting subscale coils has been manufactured at LBNL and reacted at the wire manufacturer SWCC. Selected coils are impregnated and tested in self-field, even though the coils exhibited leakage during the partial melt heat treatment. Other coils have been disassembled after reaction and submitted to critical current (Ic) tests on individual cable sections. We report on the results of the current carrying capacity of the coils. Voltage-current (VI) transitions were reproducibly measured up to a quench currents around 1400 A, which is 25% of the expected performance. The results indicate that the coils are limited by the inner windings. We further compare possibilities to use Bi-2212 and Nb₃Sn tilted solenoid, and YBa₂Cu₃O_7-delta (YBCO) racetrack inserts to increase the magnetic field in HD2, a 36 mm bore Nb₃Sn dipole magnet which recently achieved a bore magnetic field of 13.8 T. The application of Bi-2212 and/or YBCO in accelerator type magnets, if successful, will open the road to higher magnetic fields, far surpassing the limitations of Nb₃Sn magnet technology.