Dear Reader,

Welcome to the third issue of the KCDB Newsletter.
  Some facts and figures about the KCDB, Dr J. Williams, M. L. Le Mée, Dr C. Thomas
Latest news on participation in the CIPM MRA

Since the beginning of 2005, Estonia (Associate of the General Conference on Weights and Measures, CGPM) signed the CIPM MRA (Mutual Recognition Arrangement).

Consequently, the CIPM MRA has now been signed by the representatives of 64 institutes - from 45 Member States, 17 Associates of the CGPM, and two international organizations - and covers a further 96 institutes designated by the signatory or other appropriate official bodies for specific services that they do not deliver themselves.
 
Full list of signatories
Information registered in the KCDB

Appendix B: key and supplementary comparisons

Appendix B of the KCDB now covers 623 key and supplementary comparisons conducted under the auspices of the CIPM or of RMOs. These include 500 key comparisons, 176 of which have had their results published in the KCDB by 1 June 2005.

The ongoing BIPM key comparisons in Electricity are regularly updated with the results of new bilateral comparisons carried out between the BIPM and some National Metrology Institutes.
Since October 2002, results have been approved and published for 56 of the 59 ongoing BIPM key comparisons on radionuclide activity conducted within the framework of the International System of Reference (SIR).
A new BIPM key comparison, BIPM.L-K11, of primary wavelength standards is now in progress.
The results of the key comparison on time CCTF-K2001.UTC are updated each month.

  Latest KC results published

 

Appendix C: Calibration and Measurement Capabilities (CMCs)

On 1st June 2005, Appendix C of the KCDB contained some 17 500 CMCs covering all fields of metrology. They were distributed as follows:
      -3257 CMCs in the field of Ionizing radiation,
      -11245 CMCs in other fields of Physics, and
      -3004 CMCs in the field of Chemistry.

The effective number of uncertainty values published via Appendix C is now estimated to be over 35 000. This is the consequence of the implementation of "uncertainty tables", which may be used to describe more precisely the uncertainty statement that characterizes a given CMC.

Large sets of CMCs, especially those covering Ionizing Radiation from all regions, and those corresponding to the update of APMP and COOMET claims in Electricity and Magnetism, were posted over the last six months in Appendix C.

In addition, we undertake a daily update to respond to small corrections (mainly editorial), minor changes (increase of uncertainty values, reduction of the measurement ranges, etc.), and deletion of some CMCs (services that are no longer offered to clients, or that are not covered by an appropriate Quality System), as detailed in document JCRB-8/10_rev.

  Latest CMCs published
Key comparison reference values as published in Appendix B

A detailed analysis of the methods used to derive the key comparison reference value and to compute the linkage between the results of key comparisons of the same "family" (CIPM and RMO key comparisons with similar protocols) was carried out starting from those results that are published in Appendix B. Full description of this analysis is given in the document "The BIPM key comparison database (KCDB): linkage of key comparisons".

Numbers

The right-hand figure shows the distribution of the 176 key comparisons which had their results published in Appendix B on 1st June 2005.
136 are key comparisons placed at the centre of a "family", and 40 are linked key comparisons conducted by APMP, EUROMET and also some Consultative Committees.

The measurements are generally obtained for several nominal values of the measurand or of an influence parameter, leading to a total of about 360 sets of results interpreted in terms of equivalence.

Computation of the key comparison reference value

Distribution of the methods used to compute the key comparison reference values published in Appendix B on 1st June 2005 (percentage established over a set of 360 results)
Methods used for the computation of the key comparison reference values
*arithmetic mean, for instance BIPM.RI(II)-K1.Co-57

*weighted mean, for instance CCEM-K6.c

*weighted mean with maximum weight, for instance CCPR-K3.b

*median, for instance CCM.M-K3

*known values - values of international standards maintained by the BIPM, for instance BIPM.EM-K13.a, and global values known a priori, such as a ratio equal to 1, for instance BIPM.RI(I)-K2, and

*individual reference values - case of the gravimetric value of each sample distributed in some of the Chemistry key comparisons, for instance CCQM-K3
Linkage of the results as published in Appendix B

On 1st June 2005, the linked results expanded those of the corresponding central key comparisons in order to form 25 duos, three trios, and three quartets, as detailed in the document "The BIPM key comparison database (KCDB): linkage of key comparisons".
For example, the graph of equivalence obtained for the "PR-K3.b" family is shown below; it includes the results of a quartet of key comparisons.

The linkages reported in Appendix B are generally deduced from a case-by-case examination of the situation.

The different methods used are thoroughly related to the techniques put in place to conduct the comparisons and to the manner in which the key comparison reference values are computed. For instance the linkage is direct when individual or global reference values are known a priori. In the case of radionuclide activity measurements, the linkage is often based on the measurement in the SIR of some of the ampoules distributed in CCRI and RMO key comparisons. When a statistical treatment of results of common participants is carried out, it relies on the repeatability of the corresponding measurements.

 

Graph of equivalence of the "PR-K3.b" family (luminous responsivity). All values are given in percents. The symbols are: diamonds for CCPR-K3.b participants; triangle for one value amended after the CC key comparison; circles for APMP.PR-K3.b participants, squares for participants in two subsequent bilateral key comparisons. Other details on these comparisons may be found in the KCDB Website.
Workshop on the Impact of Information Technology in Metrology

A Workshop was held at the NMIJ, Tsukuba, Japan, jointly organized by the NMIJ and the BIPM, on the importance of Information Technology for Metrology. This was the second Workshop of this new series. It brought together scientists from different specialities and allowed cross-fertilization between the different groups. Themes were: e.g., remote calibration, Monte Carlo techniques, data analysis and data handling, statistical methods and software validation.

Before the main Workshop a third Workshop in a series on the analysis of key comparison results was held. It focused on the statistics, data evaluation and calculation of the reference values of key comparisons.

In total, for both events about 140 people from 27 nationalities attended and it was considered by all participants as a great success. The presentations will be published soon on the BIPM website.

Highlights from the 14th JCRB meeting

The 14th meeting of the JCRB marked a significant milestone as the committee officially closed the transition period of the CIPM MRA. Hosted by BelGIM, the Bielorussian NMI, in Minsk, on 12 May 2005, the JCRB reviewed reports from all RMOs concerning the presence of fully-implemented and accepted quality systems in all participating institutes.

After almost six years since the first signature of the CIPM MRA, hundreds of metrologists in over one hundred NMIs and designated institutes have reviewed more than 17 000 CMCs, participated in more than five hundred comparisons and implemented and reviewed their quality systems compliant with ISO/IEC 17025 and ISO Guide 34.

With this action, Appendix C achieved a new level of international recognition as all CMCs now fully satisfy all the requirements established in the CIPM MRA.

Some CMCs that do not yet comply with the quality system requirement may be reinstated in the future if the local RMO reports that they have verified that the CMCs are indeed underpinned by a fully-implemented QS.

The JCRB also approved new criteria for acceptance of CMCs in Appendix C, which were modified to delete the wording related to the transition period. After some discussion and considering that conditions vary among the different metrology areas, the committee decided to adopt a set of flexible criteria and asked the consultative committees to provide more specific guidance if it becomes necessary. The final document will be available soon on the JCRB website.

The JCRB Chairman also informed attendees that the CIPM will issue several guidance documents including clarifications to the text of the CIPM MRA, definition of a CMC, the role of associate states and designated institutes, as well as conditions for acceptance of certified reference materials and rules for subcontracting work within the CIPM MRA.
KCDB and Quality System

The work of the KCDB is detailed in nine procedures that successfully passed the BIPM Quality System internal review on 31 May 2005 for the second consecutive year. Seven of these procedures describe the technical aspects of the entry of information into the databases of the KCDB. The two additional procedures deal with the formal authorization processes needed before publishing data on the web.
Future meetings

 17th meeting of the CCU
 to be held at the BIPM, from 29 June to 1 July 2005

 Meeting of the RMO WG on CMCs in Ionizing Radiation
 to be held at the BIPM, from 1 to 2 September 2005

 21st APMP General Assembly
 Jeju, Korea, from 5 to 9 September 2005

 15th COOMET Committee Meeting
 Vilnius, Lithuania, from 8 to 9 September 2005

 Meeting of the WGDM (CCL Working Group on Dimensional Metrology)
 to be held at the BIPM, from 12 to 13 September 2005

 Meeting of the MePWG (CCL Working Group on the Mise-en-Pratique)
 to be held at the BIPM, from 12 to 13 September 2005

Meeting of the CCL-CCTF (Joint Working Group CCL/CCTF on secondary representations of the second)
to be held at the BIPM, from 13 to 14 September 2005

 12th meeting of the CCL
 to be held at the BIPM, from 15 to 16 September 2005

 15th meeting of the JCRB
 to be held at the BIPM, 29 September 2005

 Meeting of the directors of the NMIs
 to be held at the BIPM, 30 September 2005

 94th meeting of the CIPM
 to be held at the BIPM, from 4 to 7 October 2005

 SIM General Assembly
 Trinidad & Tobago, from 10 to 14 October 2005

 Meetings of the Working Groups of the CCPR
 to be held at the BIPM, 24 October 2005

 18th meeting of the CCPR
 to be held at the BIPM, from 25 to 26 October 2005