Multilayered Bi-2223 conductors for current-lead applications

The "accordion-folding method" enables us to fabricate large current carrying capacity multilayered Bi-2223 conductors suitable for applications as current lead (CL). At present, silver-gold alloys, with Au 3% and 11% wt, sheathed Bi-2223 conductors up to 500 mm long, having an overall critical current density J/sub c, eng/ exceeding 3000 A/cm/sup 2/ at 77 K are reproducibly obtained. The high J/sub c, eng/ values are a direct consequence of the high fill factor of these conductors. In this work, we first compare the low-temperature heat load for multilayered Bi-2223/Ag-Au conductors and for an optimised vapour-cooled CL and then show the results of simulations of the temperature evolution after a quench event. Self-field I/sub c/, I/sub c/(Be/sub ext/) and R/sub cont/(I) results on individual, as well as stacked multilayered, Bi-2223/Ag-Au conductors are presented and discussed in perspective of their possible use as CL.