Speaker
Description
Brookhaven National Laboratory (BNL) is building a 25 T, 100 mm cold bore HTS solenoid for the Center for Axion and Precision Physics (CAPP) at the Institute for Basic Science (IBS) in Korea to be used in their search for Dark Matter Axions. The magnet is wound using - Second Generation (2G) High Temperature Superconductor (HTS) tape from SuperPower. The combination of high magnetic field (>20 Tesla) and large aperture will result in high stresses within the magnet, with hoop stresses approaching 500 MPa (applied on the wide side of the HTS tape) and axial stresses approaching 200 MPa (applied on the narrow side of the HTS tape). While studies show that the 2G HTS tape from SuperPower with 50µm Hastelloy substrate and 20µm copper stabilizer performs within limits under hoop stresses of 500 MPa, there is no experimental data available showing the effects of high axial stress on the performance of the 2G HTS tape. To validate the conductor choice for the magnet, BNL fabricated an experimental cryogenic (77K) compression setup that would replicate the mechanical stresses the conductor and coils in the IBS magnet would experience during operation. A series of compressive tests were performed at 77K on 2G HTS tape from SuperPower with a Hastelloy substrate thickness of 50µm and copper stabilizer layer thicknesses of 65µm, 40µm, and 20µm. The initial design and several iterations in the test setup, along with the test results, will be discussed.
*This work was carried out under a research agreement between Institute of Basic Science, Korea and Brookhaven Science Associates, LLC under contract No. IBS-NF-16-32. This work was also supported by Brookhaven Science Associates, LLC under contract No. DE-SC0012704, with the U.S. Department of Energy.
