BS EN IEC 61788-4:2020
$167.15
Superconductivity – Residual resistance ratio measurement. Residual resistance ratio of Nb-Ti and Nb3Sn composite superconductors
| Published By | Publication Date | Number of Pages |
| BSI | 2020 | 40 |
IEC 61788-4:2020 is available as IEC 61788-4:2020 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 61788-4:2020 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 matrix in a strain-free condition and zero external magnetic field. This method is intended for use with superconductor specimens that have a monolithic structure with rectangular or round cross-section, RRR value less than 350, and cross-sectional area less than 3 mm2. In the case of Nb3Sn, the specimens have received a reaction heat-treatment. This fifth edition cancels and replaces the fourth edition published in 2016. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) change in the suitable distance of voltage taps on the specimen for reliable measurement, b) 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, c) revision of the confusing definitions of the copper ratio and copper fraction.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | undefined |
| 5 | Annex ZA(normative)Normative references to international publicationswith their corresponding European publications |
| 7 | English CONTENTS |
| 9 | FOREWORD |
| 11 | INTRODUCTION |
| 12 | 1 Scope 2 Normative references 3 Terms and definitions |
| 13 | 4 Principle 5 Apparatus 5.1 Material of measurement mandrel or of measurement base plate Figure 1 – Relationship between temperature and resistance |
| 14 | 5.2 Diameter of the measurement mandrel and length of the measurement base plate 5.3 Cryostat for the resistance R2 measurement 6 Specimen preparation 7 Data acquisition and analysis 7.1 Resistance R1 at room temperature Figures |
| 15 | 7.2 Resistance R2 or R2* just above the superconducting transition 7.2.1 Correction of strain effect 7.2.2 Data acquisition of cryogenic resistance |
| 16 | Figure 2 – Voltage versus temperature curves and definitions of each voltage |
| 17 | 7.2.3 Optional acquisition methods 7.3 Correction on measured of Nb-Ti composite superconductor for bending strain 7.4 Residual resistance ratio (RRR) |
| 18 | 8 Uncertainty and stability of the test method 8.1 Temperature 8.2 Voltage 8.3 Current 8.4 Dimension 9 Test report 9.1 RRR value |
| 19 | 9.2 Specimen 9.3 Test conditions 9.3.1 Measurements of R1 and R2 |
| 20 | 9.3.2 Measurement of R1 9.3.3 Measurement of R2 |
| 21 | Annex A (informative) Additional information relating to the measurement of RRR A.1 Recommendation on specimen mounting orientation A.2 Alternative methods for increasing temperature of specimen above superconducting transition temperature A.3 Alternative measurement methods of R2 or R2* |
| 23 | Figure A.1 – Definition of voltages |
| 24 | A.4 Bending strain dependency of RRR for Nb-Ti composite superconductor |
| 25 | Figure A.2 – Bending strain dependency of RRR value forpure Cu matrix of Nb-Ti composite superconductors (comparison between measured values and calculated values) Figure A.3 – Bending strain dependency of RRR value for round Cu wires |
| 26 | Figure A.4 – Bending strain dependency of normalized RRR value for round Cu wires Figure A.5 – Bending strain dependency of RRR value for rectangular Cu wires |
| 27 | A.5 Procedure of correction of bending strain effect Figure A.6 – Bending strain dependency of normalized RRR value forrectangular Cu wires Table A.1 – Minimum diameter of the measurement mandrel for round wires Table A.2 – Minimum diameter of the measurement mandrel for rectangular wires |
| 28 | Tables |
| 29 | Annex B (informative) Uncertainty considerations B.1 Overview B.2 Definitions B.3 Consideration of the uncertainty concept |
| 30 | 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 |
| 31 | B.4 Uncertainty evaluation example for IEC TC 90 standards Table B.4 – Standard uncertainties of two output signals Table B.5 – COV values of two output signals |
| 33 | Annex C (informative) Uncertainty evaluation in test method of RRR forNb-Ti and Nb3Sn composite superconductors C.1 Evaluation of uncertainty |
| 36 | C.2 Summary of round robin test of RRR of a Nb-Ti composite superconductor Table C.1 – Uncertainty of each measurement |
| 37 | C.3 Reason for large COV value in the intercomparison test on Nb3Sn composite superconductor Figure C.1 – Distribution of observed of Cu/Nb-Ti composite superconductor Table C.2 – Obtained values of RRR for six Nb3Sn specimens |
| 38 | Table C.3 – Average, standard deviation and coefficient of variation for six specimens |
| 39 | Bibliography |
