BS EN 61788-4:2011
$142.49
Superconductivity – Residual resistance ratio measurement. Residual resistance ratio of Nb-Ti composite superconductors
| Published By | Publication Date | Number of Pages |
| BSI | 2011 | 32 |
This part of IEC 61788 covers a test method for the determination of the residual resistance ratio (RRR) of composite superconductors comprised of Nb-Ti filaments and Cu, Cu-Ni or Cu/Cu-Ni matrix. This method is intended for use with superconductors that have a monolithic structure with rectangular or round cross-section, RRR less than 350, and cross-sectional area less than 3 mm2. All measurements are done without an applied magnetic field.
The method described in the body of this standard is the “reference” method and optional acquisition methods are outlined in Clause A.3.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 6 | English CONTENTS |
| 8 | INTRODUCTION |
| 9 | 1 Scope 2 Normative references 3 Terms and definitions |
| 10 | 4 Requirements 5 Apparatus 5.1 Material of measuring mandrel or of measuring base plate 5.2 Diameter of the measuring mandrel and length of the measuring base plate Figures Figure 1 – Relationship between temperature and resistance |
| 11 | 5.3 Cryostat for the resistance, R2, measurement 6 Specimen preparation 7 Data acquisition and analysis 7.1 Resistance (R1) at room temperature 7.2 Resistance (R2*) just above the superconducting transition |
| 12 | Figure 2 – Voltage (U) versus temperature (T) curves and definitions of each voltage |
| 13 | 7.3 Correction on measured R2* for bending strain |
| 14 | 7.4 Residual resistance ratio (RRR) 8 Uncertainty and stability of the test method 8.1 Temperature 8.2 Voltage measurement 8.3 Current 8.4 Dimension |
| 15 | 9 Test report 9.1 RRR value 9.2 Specimen 9.3 Test conditions |
| 17 | Annex A (informative) Additional information relating to the measurement of RRR (residual resistance ratio) |
| 18 | Figure A.1 – Definition of voltages |
| 20 | Figure A.2 – Bending strain dependency of RRR for pure Cu matrix of Nb-Ti composite superconductors (comparison between measured values and calculated values) Figure A.3 – Bending strain dependency of RRR for round Cu wires |
| 21 | Figure A.4 – Bending strain dependency of normalized RRR for round Cu wires Figure A.5 – Bending strain dependency of RRR for rectangular Cu wires |
| 22 | Figure A.6 – Bending strain dependency of normalized RRR for rectangular Cu wires |
| 23 | Annex B (informative) Uncertainty considerations |
| 24 | Tables Table B.1 – Output signals from two nominally identical extensometers Table B.2 – Mean values of two output signals Table B.3 – Experimental standard deviations of two output signals Table B.4 – Standard uncertainties of two output signals |
| 25 | Table B.5 – Coefficient of variations of two output signals |
| 27 | Annex C (informative) Uncertainty evaluation in test method of RRR for Nb-Ti |
| 29 | Table C.1 – Uncertainty of each measurement |
| 30 | Figure C.1 – Distribution of observed RRR of Cu/Nb-Ti composite superconductor |
