Ongoing BIPM Key Comparison Research Articles

Bilateral comparison of 1.018 V and 10 V standards between the NSAI–NML (Ireland) and the BIPM, March to April 2010 (part of the ongoing BIPM key comparison BIPM.EM-K11.a and b)

As a part of the ongoing BIPM key comparisons BIPM.EM-K11.a and b, a comparison of the 1.018 V and 10 V voltage reference standards of the BIPM and of the National Standards Authority of Ireland–National Metrology Laboratory (NSAI–NML), Dublin, Ireland, was carried out from March to April 2010.Two BIPM Zener diode-based travelling standards were transported by freight to NSAI–NML. At NSAI–NML, the reference standard for DC voltage is maintained at the 10 V level by means of a group of characterized Zener diode-based electronic voltage standards. The output EMF of each travelling standard, at the 10 V output terminals, was measured by direct comparison with the group standard. Measurements of the output EMF of the travelling standards at the 1.018 V output terminals were made using a potentiometer, standardized against the local 10 V reference standard. At the BIPM, the travelling standards were calibrated at both voltages before and after the measurements at NSAI–NML, using the BIPM Josephson Voltage Standard. Results of all measurements were corrected for the dependence of the output voltages on internal temperature and ambient pressure.The comparison results show that the voltage standards maintained by NSAI–NML and the BIPM were equivalent, within their stated expanded uncertainties, on the mean date of the comparison.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Bilateral comparison of 1 Ω standards (ongoing BIPM key comparison BIPM.EM-K13.a) between the NML-Ireland and the BIPM

This report describes the results obtained from a NML(Ireland)–BIPM bilateral comparison of 1 Ω resistance standards in 2008. The comparison was carried out in the framework of the BIPM ongoing key comparison BIPM.EM-K13.a. Two BIPM 1 Ω travelling standards of CSIRO type were calibrated first at the BIPM, then at the NMLI and again at the BIPM after their return. The stability of the transfer standard was such that the uncertainty associated with the transfer was significantly smaller than the uncertainty arising from the calibrations. The NMLI and the BIPM calibrations were found to be in good agreement, with a mean difference smaller than the expanded uncertainty (k = 2) of the comparison.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Bilateral comparison of 1 Ω standards (ongoing BIPM key comparison BIPM.EM-K13.a) between the NMIA (Australia) and the BIPM

This report describes the results obtained from a NMIA(Australia)–BIPM bilateral comparison of 1 Ω resistance standards in the period 2008–2009. The comparison was carried out in the framework of the BIPM ongoing key comparison BIPM.EM-K13.a. Three BIPM 1 Ω travelling standards of CSIRO type were calibrated first at the BIPM, then at the NMIA and again at the BIPM after their return. The stability of the transfer standards was such that the uncertainty associated with the transfer was significantly smaller than the uncertainty arising from the calibrations.The BIPM results are based on the conventional value RK-90. Those from the NMIA are traceable to a calculable capacitor. The uncertainty of the comparison includes therefore the standard uncertainty of 1 × 10−7 that applies to the use of the quantum Hall effect as a representation of the ohm.The NMIA and the BIPM calibrations were found to be in agreement, with a mean difference smaller than the expanded uncertainty (k = 2) of the comparison.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Bilateral comparison of 10 kΩ standards (ongoing BIPM key comparison BIPM.EM-K13.b) between the NML (Ireland) and the BIPM

This report describes the results obtained from a NML(Ireland)–BIPM bilateral comparison of 10 kΩ resistance standards in 2008. The comparison was carried out in the framework of the BIPM ongoing key comparison BIPM.EM-K13.b. Two BIPM 10 kΩ travelling standards of SR104 type were calibrated first at the BIPM, then at the NMLI and again at the BIPM after their return. The stability of the transfer standards was such that the uncertainty associated with the transfer was smaller than the uncertainty arising from the calibrations. The NMLI and the BIPM calibrations were found to be in good agreement, with a mean difference smaller than the expanded uncertainty (k = 2) of the comparison.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Bilateral comparison of 10 V standards between the NML (Ireland) and the BIPM, April to May 2009 (part of the ongoing BIPM key comparison BIPM.EM-K11.b)

As a part of the ongoing BIPM key comparison BIPM.EM-K11.b, a comparison of the 10 V voltage reference standards of the BIPM and the National Metrology Laboratory (NML), Dublin, Ireland, was carried out from April to May 2009. Two BIPM Zener diode-based travelling standards (Fluke 732B), BIPM_A (SN:7480002) and BIPM_C (SN:7195014), were transported by freight to NML. The NML measurements were carried out by comparison with the mean of the NML voltage standard.The output EMF of each travelling standard, at its 10 V output terminals, was measured by comparison with the NML voltage standard, which comprises ten commercially-produced Zener diode-based electronic voltage standards.At the BIPM, the traveling standards were calibrated with the Josephson Voltage Standard. Results of all measurements were corrected for the dependence of the output voltages on internal temperature and ambient pressure.The comparison result is very satisfactory and shows that the voltage standards maintained by the NML and the BIPM were equivalent, within their stated expanded uncertainties, on the mean date of the comparison.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Final report on the bilateral comparison of 1 Ω standards (ongoing BIPM key comparison BIPM.EM-K13.a) between the CMI (Czech Republic) and the BIPM

This report describes the results obtained from a CMI–BIPM bilateral comparison of 1 Ω resistance standards in 2007–2008. The comparison was carried out in the framework of the BIPM ongoing key comparison BIPM.EM-K13.a. Two BIPM 1 Ω travelling standards of CSIRO type were calibrated first at the BIPM, then at the CMI and again at the BIPM after their return. The stability of the transfer standard was such that the uncertainty associated with the transfer was significantly smaller than the uncertainty arising from the calibrations. The CMI and the BIPM calibrations were found to be in good agreement, with a mean difference smaller than the expanded uncertainty (k = 2) of the comparison.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Bilateral comparison of 10 kΩ standards (ongoing BIPM key comparison BIPM.EM-K13.b) between the CMI (Czech Republic) and the BIPM

This report describes the results obtained from a CMI–BIPM bilateral comparison of 10 kΩ resistance standards in 2008. The comparison was carried out in the framework of the BIPM ongoing key comparison BIPM.EM-K13.b. Two BIPM 10 kΩ travelling standards of SR104 type were calibrated first at the BIPM, then at the CMI and again at the BIPM after their return. The stability of the transfer standards was such that the uncertainty associated with the transfer was significantly smaller than the uncertainty arising from the calibrations. The CMI and the BIPM calibrations were found to be in good agreement, with a mean difference smaller than the standard uncertainty of the comparison.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Final report on the bilateral comparison of 100 pF capacitance standards (ongoing BIPM key comparison BIPM.EM-K14.b) between the NML, Ireland and the BIPM, June–October 2007

A comparison of 100 pF capacitance standards at a measuring frequency of 1 kHz was carried out between the BIPM and the NML (Ireland). Two travelling standards belonging to the BIPM were used. Measurements were made over the period June to October 2007. One of the travelling standards had to be eliminated from the comparison due to a failure of its temperature control circuit. The transport characteristics of the remaining standard were satisfactory, and the results showed agreement well within the combined uncertainty of the comparison (relative expanded uncertainty 0.78 ppm, k = 2, 95% confidence).Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Final report on the bilateral comparison of 1 Ω standards (ongoing BIPM key comparison BIPM.EM-K13.a) between the NIST (USA) and the BIPM

This report describes the results obtained from a NIST–BIPM bilateral comparison of 1 Ω resistance standards in 2007. The comparison was carried out in the framework of the BIPM ongoing key comparison BIPM.EM-K13.a. Three BIPM 1 Ω travelling standards of CSIRO type were calibrated first at the BIPM, then at the NIST and again at the BIPM after their return. The stability of the transfer standard was such that the uncertainty associated with the transfer was significantly smaller than the uncertainty arising from the calibrations. The NIST and the BIPM calibrations were found to be in good agreement, with a mean difference smaller than one standard uncertainty of the comparison.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Bilateral comparison of 1.018 V and 10 V standards between the KRISS (Republic of Korea) and the BIPM, February 2008 (part of the ongoing BIPM key comparison BIPM.EM-K11.a and b)

As a part of the ongoing BIPM key comparisons BIPM.EM-K11.a and b, a comparison of the 1.018 V and the 10 V voltage reference standards of the BIPM and the Korea Research Institute of Standards and Science (KRISS), Daejeon, Republic of Korea, was carried out in February 2008. One KRISS Zener diode (Fluke 732A) was used as a transfer standard. KRISS measurements were carried out by comparison with the KRISS primary voltage standard consisting of a Josephson Voltage Standard. BIPM measurements were carried out on site, at KRISS by comparison with the BIPM transportable Josephson Voltage Standard. The transfer standard wasn't characterized for the effects of temporal drift and environmental influences as both participants measured the Zener within a short time period. For day to day measurement, the voltage assigned by the BIPM to the transfer standard, UBIPM, was computed using a linear least-square fit to all of the data from the BIPM and referenced to the mean time of the KRISS measurements. The final result is the simple mean of the daily result over the total period of the comparison (6 days).The final result of the comparison is presented as the difference between the value assigned to a 1.018 V and 10 V standard by the KRISS, UKRISS, and that assigned by the BIPM, at the KRISS, UBIPM, which for the reference date is:at 1.018 V, UKRISS − UBIPM = 70 nV; uc = 48 nV on 2008/02/26 at 10 V, UKRISS − UBIPM = −31 nV; uc = 100 nV on 2008/02/26,where uc is the standard uncertainty associated with the measured difference, including the uncertainty of the representation of the volt at the BIPM, the uncertainty of the representation of the volt at KRISS, both based on KJ-90, and the uncertainty related to the comparison.This satisfactory result shows that the voltage standards maintained by the KRISS and the BIPM were equivalent, within their stated expanded uncertainties, on the mean date of the comparison.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Bilateral comparison of 10 V standards between the NML (Ireland) and the BIPM, May to June 2008 (part of the ongoing BIPM key comparison BIPM.EM-K11.b)

As a part of the ongoing BIPM key comparison BIPM.EM-K11.b, a comparison of the 10 V voltage reference standards of the BIPM and the National Metrology Laboratory (NML), Dublin, Ireland, was carried out from May to June 2008. Two BIPM Zener diode-based travelling standards (Fluke 732B), were transported by freight to NML.At the BIPM, the traveling standards were calibrated with the Josephson Voltage Standard. Results of all measurements were corrected for the dependence of the output voltages on ambient temperature and pressure. The NML measurements were carried out by comparison with the mean of the NML voltage standard.A least-squares method is used to reduce the data, which comprise the measured voltage differences and the predicted output EMFs of the reference devices.The final result of the comparison is presented as the difference between the value assigned to a 10 V standard by the NML, at the NML, UNML, and that assigned by the BIPM, at the BIPM, UBIPM, which for the reference date is:UNML − UBIPM = −0.56 µV; uc = 1.32 µV on 2008/05/28,where uc is the standard uncertainty associated with the measured difference, including the uncertainty of the representation of the volt at the BIPM, the uncertainty of the representation of the volt at NML, and the uncertainty related to the comparison.This satisfactory result shows that the voltage standards maintained by the KRISS and the BIPM were equivalent, within their stated expanded uncertainties, on the mean date of the comparison.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).