A superconducting multi-ribbon shielding tube

Until now superconducting magnetic field shielding and trapping devices have been constructed by using the tentative guideline that macroscopic persistent current paths should not be cut by a normal or non-conducting barrier. Deviating from this practice a shielding tube of 190.5 mm length, 25 mm length, 25 mm bore and 15 mm wall thickness has been constructed by winding simultaneously 31 Nb/sub 3/Sn ribbon conductors of 12.7 mm width. No field leak-in was observed when the device was exposed to magnetic fields perpendicular to the axis up to 2.7 T in the shielding mode. The device has been shown to operate up to 2.4 T in trapping mode. (6 refs).