BS EN IEC 61788-4 is the fourth part of a multi-series that specifies a test method for the determination of the residual resistance ratio (RRR) of Nb-Ti and Nb3Sn composite superconductors with Cu, Cu-Ni, Cu/Cu-Ni, and Al a matrix in a strain-free condition and zero external magnetic fields.
The methods described in BS EN IEC 61788-4 are intended for use with superconductor specimens that have a monolithic structure with rectangular or round cross-section, RRR values less than 350, and cross-sectional area less than 3 mm2. In the case of Nb3Sn, the specimens have received a reaction heat treatment.
BS EN IEC 61788-4 on superconductivity is relevant to:
Superconductivity is the ability of certain materials to conduct electric current with practically zero resistance. The RRR is defined as a ratio of the resistance of the superconductor at room temperature to that just above the superconducting transition.
BS EN IEC 61788-4 specifies the test method for residual resistance ratio of Nb-Ti and Nb3Sn composite superconductors. The curve method is employed for the measurement of the resistance just above the superconducting transition.
As a result, evaluating the RRR with BS EN IEC 61788-4 helps in the selection of the right samples of copper, Cu/Cu-Ni or aluminium, ensuring of quality and purity. In addition, the lack of impurities, dislocations and crystallographic defects could ensure that superconductivity does not get interrupted.
BS EN IEC 61788-4:2020supersedes BS EN 61788‑4:2016, which is withdrawn, and the following technical changes were introduced:
IEC 61788-4 Ed.5.0
EN 61788-4 Ed.5.0