IEC 61788-4:2011

Superconductivity - Part 4: Residual resistance ratio measurement - Residual resistance ratio of Nb-Ti composite superconductors

IEC 61788-4:2011 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. This third edition constitutes a technical revision which adds two new annexes: "Uncertainty considerations" (Annex B) and "Uncertainty evaluation in test method of RRR for NbTi" (Annex C). Copper is used as a matrix material in multifilamentary superconductors and works as an electrical shunt when the superconductivity is interrupted. It also contributes to recovery of the superconductivity by conducting heat generated in the superconductor to the surrounding coolant. The cryogenic-temperature resistivity of copper is an important quantity, which influences the stability of the superconductor. The residual resistance ratio is defined as a ratio of the resistance of the superconductor at room temperature to that just above the superconducting transition.

Supraconductivité - Partie 4: Mesure du rapport de résistance résiduelle - Rapport de résistance résiduelle des supraconducteurs composites de Nb-Ti

La CEI 61788-4:2011 spécifie une méthode d'essai pour la détermination du rapport de résistance résiduelle (RRR) de supraconducteurs composites constitués de filaments de Nb-Ti et d'une matrice de Cu, Cu-Ni ou Cu/Cu-Ni. Cette méthode est destinée à être utilisée avec des supraconducteurs présentant une structure monolithique avec une section rectangulaire ou circulaire, un rapport RRR inférieur à 350 et une surface de section inférieure à 3 mm2. Toutes les mesures sont effectuées sans appliquer de champ magnétique. La méthode décrite dans le corps de texte de la présente norme est la méthode de "référence" et des méthodes d'acquisition facultatives sont présentées à l'Article A.3. Cette troisième édition constitue une révision technique qui ajoute deux nouvelles annexes: "Considérations relatives à l'incertitude" (Annexe B) et "Evaluation de l'incertitude de la méthode d'essai de RRR (rapport de résistance résiduelle) de NbTi" (Annexe C). Le cuivre est utilisé comme matériau de matrice dans les supraconducteurs multifilamentaires et fonctionne comme une dérivation électrique lorsque la supraconductivité est interrompue. Il contribue également à la reprise de la supraconductivité en dirigeant la chaleur générée dans le supraconducteur vers le fluide de refroidissement environnant. La résistivité à la température cryogénique du cuivre est une grandeur importante qui influe sur la stabilité du supraconducteur. Le rapport de résistance résiduelle est défini comme le rapport entre la résistance du supraconducteur à température ambiante et celle immédiatement supérieure à la transition supraconductrice.

General Information

• Status: Published
• Publication Date: 10-Jul-2011
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• ICS: 29.050 - Superconductivity and conducting materials
• Technical Committee: TC 90 - Superconductivity
• Drafting Committee: WG 4 - TC 90/WG 4
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 19-Jan-2016

Relations

• Revised: IEC 61788-4:2016 - Superconductivity - Residual resistance ratio measurement - Residual resistance ratio of Nb-Ti and Nb₃Sn composite superconductors
• Effective Date: 05-Sep-2023
• Revises: IEC 61788-4:2007 - Superconductivity - Part 4: Residual resistance ratio measurement - Residual resistance ratio of Nb-Ti composite superconductors
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61788-4 ®
Edition 3.0 2011-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Superconductivity –
Part 4: Residual resistance ratio measurement – Residual resistance ratio of
Nb-Ti composite superconductors

Supraconductivité –
Partie 4: Mesure du rapport de résistance résiduelle – Rapport de résistance
résiduelle des supraconducteurs composites de Nb-Ti

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IEC 61788-4 ®
Edition 3.0 2011-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Superconductivity –
Part 4: Residual resistance ratio measurement – Residual resistance ratio of
Nb-Ti composite superconductors

Supraconductivité –
Partie 4: Mesure du rapport de résistance résiduelle – Rapport de résistance
résiduelle des supraconducteurs composites de Nb-Ti

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 17.220.20; 29.050 ISBN 978-2-88912-554-8

– 2 – 61788-4  IEC:2011
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Requirements . 8
5 Apparatus . 8
5.1 Material of measuring mandrel or of measuring base plate . 8
5.2 Diameter of the measuring mandrel and length of the measuring base plate . 8
5.3 Cryostat for the resistance, R , measurement . 9
6 Specimen preparation. 9
7 Data acquisition and analysis . 9
7.1 Resistance (R ) at room temperature . 9
7.2 Resistance (R *) just above the superconducting transition . 9
7.3 Correction on measured R * for bending strain . 11
7.4 Residual resistance ratio (RRR) . 12
8 Uncertainty and stability of the test method . 12
8.1 Temperature . 12
8.2 Voltage measurement. 12
8.3 Current . 12
8.4 Dimension . 12
9 Test report. 13
9.1 RRR value . 13
9.2 Specimen . 13
9.3 Test conditions . 13
Annex A (informative) Additional information relating to the measurement of RRR . 15
Annex B (informative) Uncertainty considerations . 21
Annex C (informative) Uncertainty evaluation in test method of RRR for Nb-Ti . 25

Figure 1 – Relationship between temperature and resistance. emperature T * is that at
c
the intersection point . 8
Figure 2 – Voltage (U) versus temperature (T) curves and definitions of each voltage . 10
Figure A.1 – Definition of voltages . 16
Figure A.2 – Bending strain dependency of RRR for pure Cu matrix of Nb-Ti composite
superconductors (comparison between measured values and calculated values) . 18
Figure A.3 – Bending strain dependency of RRR for round Cu wires . 18
Figure A.4 – Bending strain dependency of normalized RRR for round Cu wires . 19
Figure A.5 – Bending strain dependency of RRR for rectangular Cu wires . 19
Figure A.6 – Bending strain dependency of normalized RRR for rectangular Cu wires . 20
Figure C.1 – Distribution of observed RRR of Cu/Nb-Ti composite superconductor . 28

Table B.1 – Output signals from two nominally identical extensometers . 22
Table B.2 – Mean values of two output signals . 22

61788-4  IEC:2011 – 3 –
Table B.3 – Experimental standard deviations of two output signals. 22
Table B.4 – Standard uncertainties of two output signals . 22
Table B.5 – Coefficient of variations of two output signals. 23
Table C.1 – Uncertainty of each measurement . 27

– 4 – 61788-4  IEC:2011
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SUPERCONDUCTIVITY –
Part 4: Residual resistance ratio measurement –
Residual resistance ratio of Nb-Ti composite superconductors

FOREWORD
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International Standard IEC 61788-4 has been prepared by IEC technical committee 90:
Superconductivity.
This third edition cancels and replaces the second edition published in 2007. It constitutes a
technical revision. The main revisions are the addition of two new annexes, "Uncertainty
considerations" (Annex B) and "Uncertainty evaluation in test method of RRR for NbTi"
(Anne
...