High Temperature Superconductors for High Field Superconducting Magnets

摘要

Ionization cooling, a method for shrinking the size of a muon beam, requires a low Z energy absorber, high field magnets, and high gradient radio frequency cavities. The use of high temperature superconductors (HTS) for the high field superconducting magnets is being considered to realize a helical muon cooling channel using hydrogen refrigeration. A test stand was set up at Fermilab to perform critical current (Ic) measurements of HTS wires under externally applied perpendicular and parallel fields at various temperatures. A description of the test setup and results on (Bi,Pb)2Sr2Ca2Cu3Ox (BSCCO-2223) tapes and Bi2Sr2CaCu2O8 (BSCCO-2212) round wires are presented. Finally, the engineering critical current density, JE, of HTS and Nb3Sn were compared in the application's field and temperature range of interest.