Permanent multipole magnetic fields stored in superconductors

Abstract

Hollow superconducting cylinders of Pb, Nb, and Nb3Sn were used to permanently store dipole, quadrupole, and sextupole magnetic fields with high fidelity to the original fields. Fields were trapped transversely to the axes of solid, hollow, and split hollow cylinders. This experimental demonstration indicates that it should be possible to store any multipole magnetic field configuration by this method. Important benefits should accrue to technologies dealing with the focusing of charged particle beams, such as accelerators, electron microscopes, etc. Use of field trapping permits determination of the fluxoid pinning force.