What is BS EN IEC 61788-4 about?
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.
Who is BS EN IEC 61788-4 for?
BS EN IEC 61788-4 on superconductivity is relevant to:
- Electronics industry
- Telecommunications industry
- Electrical engineers
- Manufacturers of electronic equipment and components
Why should you use BS EN IEC 61788-4?
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.
What’s changed since the last update?
BS EN IEC 61788-4:2020supersedes BS EN 61788‑4:2016, which is withdrawn, and the following technical changes were introduced:
- Change in the suitable distance of voltage taps on the specimen for reliable measurement
- New report on the result of the round-robin test of the residual resistance ratio of Nb3Sn
- Superconductors that proves the validity of the measurement method in this standard, revision of the confusing definitions of the copper ratio and copper fraction