IEC 61788-4:2016 pdf free download.SUPERCONDUCTIVITY - PART 4: RESIDUAL RESISTANCE RATIO MEASUREMENT - RESIDUAL RESISTANCE RATIO OF NB-TI AND NBSN COMPOSITE SUPERCONDUCTORS. Copper, Cu/Cu-Ni or aluminium is used as matrix material in Nb-Ti and Nb3Sn composite superconductors and works as an electrical shunt when the superconductivity is interrupted. It also contributes to recovery of the superconductivity by conducting heat generated...