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IEC 61788-23
Edition 2.0 2021-08
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Superconductivity –
Part 23: Residual resistance ratio measurement – Residual resistance ratio
of cavity-grade Nb superconductors
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IEC 61788-23
Edition 2.0 2021-08
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Superconductivity –
Part 23: Residual resistance ratio measurement – Residual resistance ratio
of cavity-grade Nb superconductors
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.220; 29.050 ISBN 978-2-8322-4958-1
– 2 – IEC 61788-23:2021 RLV © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 2
1 Scope . 7
2 Normative references. 7
3 Terms and definitions . 7
4 Principle . 8
5 Measurement apparatus . 9
5.1 Mandrel or base plate . 9
5.2 Cryostat and support of mandrel or base plate . 9
6 Specimen preparation . 10
7 Data acquisition and analysis . 11
7.1 Data acquisition hardware . 11
7.2 Resistance (R ) at room temperature . 11
7.3 Residual resistance (R ) just above the superconducting transition . 11
7.4 Validation of the residual resistance measurement . 13
7.5 Residual resistance ratio . 13
8 Uncertainty of the test method . 13
9 Test report. 13
9.1 General . 13
9.2 Test information . 13
9.3 Specimen information . 14
9.4 Test conditions . 14
9.5 RRR value . 14
Annex A (informative) Additional information relating to the measurement of RRR . 15
A.1 Considerations for specimens and apparatus . 15
A.2 Considerations for specimen mounting orientation . 16
A.3 Alternative methods for increasing temperature of specimen above
superconducting transition temperature . 16
A.3.1 General . 16
A.3.2 Heater method . 16
A.3.3 Controlled methods . 16
A.4 Other test methods . 16
A.4.1 General . 16
A.4.2 Measurement of resistance versus time . 17
A.4.3 Comparison of ice point and room temperature . 17
A.4.4 Extrapolation of the resistance to 4,2 K . 17
A.4.5 Use of magnetic field to suppress superconductivity at 4,2 K . 18
A.4.6 AC techniques . 18
Annex B (informative) Uncertainty considerations . 19
B.1 Overview. 19
B.2 Definitions . 19
B.3 Consideration of the uncertainty concept . 20
B.4 Uncertainty evaluation example for IEC TC 90 standards . 22
Annex C (informative) Uncertainty evaluation for resistance ratio measurement of Nb
superconductors . 24
C.1 Evaluation of uncertainty . 24
C.1.1 Room temperature measurement uncertainty . 24
C.1.2 Cryogenic measurement uncertainty . 25
C.1.3 Estimation of uncertainty for typical experimental conditions . 27
C.2 Round robin test Inter-laboratory comparison summary . 28
Bibliography . 29
Figure 1 – Relationship between temperature and resistance near the superconducting
transition . 8
Figure A.1 – Determination of the value of R from a resistance versus time plot . 17
Figure C.1 – Graphical description of the uncertainty of regression related to the
measurement of R . 27
Table B.1 – Output signals from two nominally identical extensometers . 20
Table B.2 – Mean values of two output signals . 20
Table B.3 – Experimental standard deviations of two output signals . 21
Table B.4 – Standard uncertainties of two output signals . 21
Table B.5 – Coefficients of variation of two output signals . 21
Table C.1 – Uncertainty of measured parameters . 27
Table C.2 – RRR values obtained by round robin test inter-laboratory
comparison using liquid helium . 28
– 4 – IEC 61788-23:2021 RLV © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SUPERCONDUCTIVITY –
Part 23: Residual resistance ratio measurement –
Residual resistance ratio of cavity-grade Nb superconductors
FOREWORD
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This redline version of the official IEC Standard allows the user to identify the changes made to
the previous edition IEC 61788-23:2018. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.
IEC 61788-23 has been prepared by IEC technical committee 90: Superconductivity. It is an
International Standard.
This second edition cancels and replaces the first editio
...