Design and fabrication of a 30 T superconducting solenoid using overpressure processed Bi2212 round wire

High field magnets are needed for frontier accelerator facilities and have many applications beyond high-energy physics. Of particular interest are 30-40T class (LTS/HTS hybrid) solenoids required for the final beam cooling stages of a muon collider facility. The successful design of such magnets using Bi2212 conductor depends critically on the conductor processing, stress management in the coil, and quench protection. These are the challenges addressed in the proposal and the overall objectives of the combined Phase I and Phase II projects. Bi2212 round wire conductor will be evaluated for accelerator use by concentrating on the design of a solenoid magnet that will be the enabling technology for realizing the final stages of muon beam cooling and thus a high luminosity muon collider. A full mechanical characterization of a test coil made from overpressure-processed conductor with engineering current density JE in the range of & gt;600 A/mm2 at 20-30 T will be performed. The data from the test coil will serve as input to a 30+ T magnet that will be designed, built, and tested to demonstrate the suitability of overpressure-processed Bi2212 for solenoids for final muon cooling and 6D cooling channels. Short lengths and coils wound from up to 100 m length conductor will be overpressure processed. Characterization of an overpressure processed Bi2212 round-wire based solenoid will be performed at 4.2 K in a background field of up to 14 T. The characterization will include mechanical, thermal, and quench properties. The data will be used as input to a 30+ T coil design that has suitable stress management and quench protection, to be built and tested in Phase II. Commercial applications and other benefits: The technology developed by this work will benefit high-energy physics applications. The knowledge and expertise gained from this project will enable the development of very high-field solenoids, dipoles, and quadrupoles using Bi2212 cable at low temperature for applications in future particle accelerators. The technology will also extend the range available to Nuclear Magnetic Resonance Spectroscopy, an important technique used to understand molecular structures of proteins and other materials.