IEC 61788-4:2007
(Main)Superconductivity - Part 4: Residual resistance ratio measurement - Residual resistance ratio of Nb-Ti composite superconductors
Superconductivity - Part 4: Residual resistance ratio measurement - Residual resistance ratio of Nb-Ti composite superconductors
This part of IEC 61788 covers a test method for the determination of the residual resistance ratio (RRR) of a composite superconductor 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. This second edition cancels and replaces the first edition published in 2001. It constitutes a technical revision. The main revisions are the replacement of "accuracy" by "uncertainty" and a change in Figure 1, where the relationship between temperature and voltage is changed to the relationship between temperature and resistance.
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INTERNATIONAL IEC
STANDARD 61788-4
Second edition
2007-04
Superconductivity –
Part 4:
Residual resistance ratio measurement –
Residual resistance ratio of Nb-Ti
composite superconductors
Reference number
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INTERNATIONAL IEC
STANDARD 61788-4
Second edition
2007-04
Superconductivity –
Part 4:
Residual resistance ratio measurement –
Residual resistance ratio of Nb-Ti
composite superconductors
PRICE CODE
Commission Electrotechnique Internationale T
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
– 2 – 61788-4 © IEC:2007(E)
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope.6
2 Normative references .6
3 Terms and definition.6
4 Requirements .7
5 Apparatus.7
5.1 Material of measuring mandrel or of measuring base plate .7
5.2 Diameter of the measuring mandrel and length of the measuring base plate.7
5.3 Cryostat for the resistance, R , measurement .8
6 Specimen preparation.8
7 Data acquisition and analysis .8
7.1 Resistance (R ) at room temperature .8
7.2 Resistance (R *) just above the superconducting transition.8
7.3 Correction on measured R * for bending strain.11
7.4 Residual resistance ratio (RRR) .11
8 Uncertainty and stability of the test method .11
8.1 Temperature.11
8.2 Voltage measurement.11
8.3 Current.11
8.4 Dimension .12
9 Test report.12
9.1 RRR value.12
9.2 Specimen .12
9.3 Test conditions.12
9.3.1 Report of test conditions.12
9.3.2 Report of R .13
9.3.3 Report of R .13
Annex A (informative) Additional information relating to the measurement of RRR .14
Annex B (informative) Statistical definitions .22
Figure 1 – Relationship between temperature and resistance .7
Figure 2 – Voltage versus temperature curves and definitions of each voltage.9
Figure A.1 – Bending strain dependency of RRR for pure Cu matrix of Nb-Ti composite
superconductors (comparison between measured values and calculated values) .15
Figure A.2 – Bending strain dependency of RRR for round Cu wires .15
Figure A.3 – Bending strain dependency of normalized RRR for round Cu wires .16
Figure A.4 – Bending strain dependency of RRR for rectangular Cu wires .16
Figure A.5 – Bending strain dependency of normalized RRR for rectangular Cu wires .17
Figure A.6 – Distribution of observed RRR of Cu/Nb-Ti composite superconductor .19
Figure A.7 – Definition of voltages .20
61788-4 © IEC:2007(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
SUPERCONDUCTIVITY –
Part 4: Residual resistance ratio measurement –
Residual resistance ratio of Nb-Ti composite superconductors
FOREWORD
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61788-4 has been prepared by IEC technical committee 90:
Superconductivity.
This second edition cancels and replaces the first edition published in 2001. It constitutes a
technical revision. The main revisions are the replacement of “accuracy” by “uncertainty” and
a change in Figure 1, where the relationship between temperature and voltage is changed to
the relationship between temperature and resistance.
The text of this standard is based on the following documents:
FDIS Report on voting
90/203/FDIS 90/205/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
– 4 – 61788-4 © IEC:2007(E)
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 61788 series, published under the general title Superconductivity,
can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
61788-4 © IEC:2007(E) – 5 –
INTRODUCTION
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.
In this International Standard, the test method of residual resistance ratio of Nb-Ti composite
superconductors is described. The curve method is employed for the measurement of the
resistance just above the superconducting transition. Other methods are described in
Clause A.4.
– 6 – 61788-4 © IEC:2007(E)
SUPERCONDUCTIVITY –
Part 4: Residual resistance ratio measurement –
Residual resistance ratio of Nb-Ti composite superconductors
1 Scope
This part of IEC 61788 covers a test method for the determination of the residual resistance
ratio (RRR) of a composite superconductor 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 mm . 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.4.
2 Normative references
The following referenced document is indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of
the referenced document (including any amendments) applies.
IEC 60050-815, International Electrotechnical Vocabulary (IEV) – Part 815: Superconductivity
3 Terms and definition
For the purpose of this document, the terms and definitions given in IEC 60050-815 and the
following apply.
residual resistance ratio
RRR
the ratio of resistance at room temperature to the resistance just above the superconducting
transition.
In this standard for Nb-Ti composite superconductors, the room temperature is defined as
20 °C, and the residual resistance ratio is obtained in equation (1) below where the resistance
(R ) at 20 °C is divided by the resistance (R ) just above the superconducting transition.
1 2
R
RRR = (1)
R
Figure 1 shows schematically a resistanc
...
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