News from the BIPMBIPM BULLETIN

This is the fourth newsletter designed to increase the level of communication between the BIPM and its Member States. It supplements the formal reports required under the Metre Convention and highlights some key issues and achievements from Session I of the 100th meeting of the CIPM and the other important meetings held in May 2011. My aim is to keep you in touch with the BIPM’s work and, as always, I am happy to respond with further details should you wish.

Best regards,Michael Kühne, Director

www.bipm.orgAugust 2011

New States Parties to the Metre Convention and Associates of the CGPM

Saudi Arabia became a State Party to the Metre Convention on 11 February 2011

Zambia became an Associate of the CGPM on 10 December 2010

Bosnia and Herzegovina became an Associate of the CGPM on 24 May 2011

Montenegro became an Associate of the CGPM on 1 August 2011

There are now 55 States Parties to the Metre Convention and 34 Associates to the CGPM.

Session I of the 100th meeting of the CIPM

The main topics of Session I were the BIPM’s draft Programme of Work and budget for the years 2013 to 2016 and a discussion of alternative funding scenarios and the approval of the BIPM financial statements. At the 99th meeting of the CIPM, several members had remarked that it was unlikely that all the scientific activities proposed in the Programme of Work could be funded in view of the difficult economic situation being experienced in a number of States. In response to these remarks as well to those made by the NMI Directors during their meeting in 2010, the BIPM developed four different funding scenarios. These scenarios ranged from full funding for the proposed Programme of Work, including the linear accelerator project, through to a ‘worst case’ scenario which would require a reduction in BIPM core activities. Details of the scenarios are given later in this newsletter. The scenarios were thoroughly discussed and examined by the CIPM before being presented at the meeting of representatives of States Parties to the Metre Convention on 26 to 27 May 2011.A detailed presentation of the 2010 BIPM financial statements and of the 2010 Pension and Provident Fund financial statements was made to the CIPM. After the external auditor presented his report to the CIPM on these financial statements, the CIPM unanimously gave quietus to the Director and the Financial and Administrative Director of the BIPM for the 2010 BIPM financial statements. The 2009 BIPM financial statements restated according to IPSAS on an accrual basis were also approved.

The 100th meeting of the CIPM will be held in two sessions. Session I took place on 24 May 2011 at the BIPM prior to the meeting of National Metrology Institute (NMI) Directors and the informal meeting of representatives of States Parties to the Metre Convention. Session II will be held on 12 to 14 October 2011, just before the 24th meeting of the CGPM. Session II will include a celebration of the 100th meeting of the CIPM. Future meetings of the CIPM will be held in May-June of each year instead of October. This change will allow the approval of the BIPM financial statements by the CIPM, shortly after the auditors’ report is issued.

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The other important topic discussed at Session I of the meeting of the CIPM was the governance of the BIPM. This followed the submission of three draft resolutions on the governance of the BIPM by the Swiss Confederation (Draft Resolution K); the United Kingdom of Great Britain and Northern Ireland (Draft Resolution L); and the French Republic (Draft Resolution M). These draft resolutions have been duly sent to the States Parties to the Metre Convention. The CIPM concluded that a review of the governance and long-term strategy of the BIPM was needed and, as a result, the CIPM has prepared an additional draft resolution on governance issues, and on the role, mission, objectives and long-term strategy of the BIPM

Meeting of National Metrology Institute Directors

A meeting of NMI Directors was held at the BIPM on 25 May 2011. The main areas of discussion were: the present situation of the redefinition of some units of the SI and on the draft resolution of the CIPM on the possible future revision of the SI; the BIPM’s Programme of Work 2013 to 2016 and the long-term perspective for the BIPM; update of the CIPM MRA; and the present situation on the rapprochement between the BIPM and OIML. The results of the discussions are summarized as follows:

• Clarification was provided on the future role of the BIPM and the impact on the BIPM Programme of Work of the redefinition of certain base units of the SI; and the importance of publicizing issues relating to the redefinitions was highlighted. The timetable for the redefinitions was discussed, with 2015 suggested as the earliest possible date as the situation stands at the moment.

• The BIPM’s Programme of Work and budget for 2013 to 2016 was described in detail, and four different potential funding scenarios were presented (see details of the scenarios later in this newsletter). In particular, the worst case scenario would represent a major change for the BIPM as it would require the present level of expenditure to be reduced by 1.4 M Euros with a corresponding reduction in core activities. A clear statement of the ramifications and consequences of adopting such a scenario is needed. The measures that would need to be implemented under this funding scenario would do permanent damage to the BIPM in terms of loss of expertise.

• The need for an updated long-term strategy for the BIPM was stressed. It is essential that this strategy is prepared before the CGPM Meeting in 2015. Development of a ‘World metrology strategic plan’ for the entire world-wide metrological community was suggested.

which was also duly circulated to the Member States (Resolution N) for consideration during the 24th meeting of the CGPM in October 2011.Preparations for the Meeting of NMI Directors on 25 May 2011 and the informal meeting of representatives of States Parties to the Metre Convention on 26 to 27 May 2011 were discussed at Session I of the 100th meeting of the CIPM.Finally, the members of the CIPM decided on the preparations for the appointment of the next Director of the BIPM which will begin in the near future; this will ensure that a successor is in place when Prof. Michael Kühne retires in March 2014.

• The unique and invaluable work that the BIPM undertakes on the metrology of pure organic chemicals was highlighted by participants.

• All participants agreed that the CIPM MRA is a success. The various points of an addendum to the CIPM MRA were presented and discussed. The revised addendum will be sent out for written approval with a deadline for replies.

• Discussions involving a potential rapprochement between the BIPM and OIML are ongoing.

The three draft resolutions on the governance of the BIPM submitted by the Swiss Confederation (Draft Resolution K); the United Kingdom of Great Britain and Northern Ireland (Draft Resolution L); and the French Republic (Draft Resolution M) were presented to the NMI Directors. All three proposals stem mainly from the strategic issue of the role of the BIPM in relation to the NMIs. The main points of the discussions on the draft resolutions were:

• More contact is needed between the Member States, NMI Directors and the BIPM and the Member States and the NMI Directors would like to be consulted more regularly.

• Accountability, decision making and transparency within the CIPM were suggested as areas for improvement.

• The governance of the BIPM should be revised. There is a need to develop an updated long-term strategy in order to be able to agree on the short- and medium-term development of and investments in the BIPM.

A meeting of representatives of States Parties to the Metre Convention to discuss the BIPM Programme of Work and the corresponding budget for 2013 to 2016 took place at the BIPM from 26 to 27 May 2011. The agenda included presentations of the activities of the BIPM scientific departments and a tour of the BIPM laboratories. As well as discussing the Programme of Work and budget, the four different funding scenarios with their long-term consequences for the future of the BIPM were presented:

Scenario IProposed Programme of Work.

Scenario IIProposed Programme of Work with the option of financing the linear accelerator (LINAC) by voluntary contributions.

Scenario IIIContinuation of present activities with an adjustment for inflation to allow the current level of effort to be maintained.

Scenario IVNo increase in contributions from Member States, no inflationary increase and consequently a reduction or discontinuation of activities.

During a closed session (without the presence of any CIPM members who were not part of government delegations and without any BIPM staff members) the representatives discussed the BIPM’s Programme of Work for 2013-2016, the funding scenarios and other issues. The results of the closed session were summarized by the representatives of the States as follows:

1. All States strongly support and appreciate the Metre Convention and the work of the BIPM, noting that it is moving forward, for example with the development of the CIPM MRA.

2. The range of views on funding scenarios stretched from support for Scenario I and II to a desire for a less than Scenario IV, with the majority

tending to be around III or IV. Some Member States indicated that they are willing to support the BIPM with additional voluntary contributions. Other Member States expressed their view that such contributions should not incur continuing obligations.

3. There was unanimous support for a new and stronger strategic direction for BIPM with a clear idea of priorities, developed jointly between Member States, NMIs and the CIPM.

4. Some Member States question the current balance between coordinating activities and scientific and technical work and whether it is still appropriate for the future.

5. A key aspect of the new strategy will be consideration of the appropriate roles of BIPM, Regional Metrology Organizations and NMIs.

6. One interesting recommendation was that BIPM should consider whether it would be appropriate to charge for some of their services and to share costs for joint activities with other organizations.

7. Discussions on the modernization of governance structures should go in parallel with strategic developments.

8. There is a strong feeling that changes should not wait until the next scheduled CGPM in 2015.

The three government-initiated draft resolutions related to the governance of the BIPM, that were presented and discussed at the meeting, provided valuable feedback to the CIPM over concerns expressed by a number of delegations. With the encouragement of the representatives of States Parties to the Metre Convention, the CIPM was prompted to initiate an additional draft resolution on governance issues (Resolution N) for consideration during the 24th meeting of the CGPM in October 2011. Overall the meeting proved to be very successful and was seen as a valuable communication forum. It was recommended that it should be held on a regular basis, perhaps annually.

Meeting of representatives of States Parties to the Metre Convention to discuss the Programme of Work and the corresponding budget for 2013 to 2016

The CIPM MRA

So far in 2011, the National Metrology Institutes (NMIs) of seven States have signed the CIPM MRA: Zimbabwe on 14 January 2011; Zambia on 3 February 2011; Mauritius on 9 March 2011; Bangladesh on 25 March 2011; Saudi Arabia on 25 May 2011; Bosnia and Herzegovina on 15 June 2011 and Pakistan on 6 July 2011.At the time of this newsletter, the CIPM MRA has been signed by the representatives of 86 institutes – from 50 Member States, 33 Associates of the CGPM, and 3 international organizations – and covers a further 137 institutes designated by the signatory bodies.

Dr David T. Burns, Principal Physicist in the BIPM’s Ionizing Radiation Department, has been elected a Fellow of the Institute of Physics in the UK, in recognition of his personal contribution to the advancement of physics. The BIPM is proud to announce this honour in acknowledgment of his scientific research, publications, international standing and supervision of the BIPM international dosimetry standards programme.

David Burns elected as a Fellow of the Institute of Physics

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The BIPM watt balance

The watt balance is one of the BIPM’s most important projects, which was given highest priority in the Programme of Work 2009 to 2012. This project, together with the ensemble of mass standards, is essential for the BIPM’s future responsibility for mass metrology after the redefinition of the kilogram.

The distinguishing characteristic of the BIPM watt balance with respect to all other watt balances world-wide is that it carries out both measurement phases (weighing and moving experiments) simultaneously. The great advantage of this simultaneous measurement is to guarantee that the geometric properties of the coil, the coil orientation and the magnetic field, acting in both phases are strictly the same. The disadvantage is the appearance of an undesirable voltage drop in the coil, which is a result of the current flow and the non-zero resistance of the coil. This undesirable voltage drop needs to be separated from the induced voltage with an uncertainty of 1 part in 108. Such high accuracy is difficult to achieve at room temperature due to the resistance changes in the coil as a consequence of its temperature coefficient.A feasibility study was carried out to investigate the behaviour of a superconducting coil, with support from NIST, and to explore some of the engineering difficulties of developing a cryogenic watt balance. Construction of a small-scale superconducting moving coil system has started.

In early 2010 the BIPM watt balance measured, for the first time, the Planck constant h in air at atmospheric pressure. It demonstrated at a level of parts in 105, that it is possible to realize the two-phase principle originally proposed by B.P. Kibble in 1975 using only one phase by measuring all quantities at once. The reproducibility of the Planck constant measurement, at the present time, is 5.6 × 10–6. The relative difference between this result and the recommended CODATA 2006 value is – 4.8 × 10–6. The total relative uncertainty of h is currently 4.9 × 10–5. With this result, the BIPM joined NIST, NPL and METAS as the only bodies with published results of watt balance experiments. Picard A., Bradley M.P., Fang H., Kiss A., de Mirandes E., Parker B., Solve S., Stock M., The BIPM Watt Balance: Improvements and Developments, IEEE Trans. Inst. Meas., 2011, 60(7), 2378–2386

Significant progress has been made on the watt balance since the first measurements of h were made:

• Measurement of the vertical coil movement and the related velocity has improved following the installation of a 3-axis heterodyne interferometer.

Progressing from a 1-axis to a 3-axis interferometer has improved the voltage to velocity signal to noise ratio by a factor of 10 and the relative uncertainty on h has improved.

• An original procedure has been developed and tested to ensure that the electric force exerted on the watt balance coil is parallel to the gravitational force exerted on the test mass. During this procedure the electric plane of the coil is aligned perpendicular to the local gravity vector, and the magnetic field is aligned to be radial to the coil. The alignment procedure has been tested with a trial coil which has the same characteristics as the final watt balance coil (1200 turns, 250 mm diameter). The results were successful, proving that the electric force can be made parallel to the gravitational force to within 50 µrad. This accuracy is enough to allow h to be measured at the 10–8 level. This alignment will be carried out with the real watt balance coil in the near future.

• A new laboratory with two large concrete foundations, one for the watt balance, the other for a gravimeter, is now ready. The vibration level on these foundations is considerably lower than at the present location, which will reduce the noise level of the measurements. The move to the new laboratory will provide the opportunity to install the watt balance in a vacuum enclosure which is now available. With all these improvements, an uncertainty of the order of 1 part in 106 is expected to be reached in early 2012.

• A new closed magnet circuit will be soon integrated into the experiment. The design and fabrication of the two samarium-cobalt (Sm2Co17) magnets has been completed. The circuit design includes two discs of Sm2Co17 magnets, magnetized in opposite directions, as the flux source. The yoke is made of FeNi which has been selected for its high magnetic permeability and its mechanical stability at cryogenic temperatures. The mean diameter of the circular air gap is 250 mm and the width is 13 mm. The magnetic field will have radial symmetry and a magnetic flux density of about 0.5 T. Construction of the housing for the magnets is under way. One of the properties of the system is that the magnets and the air gap are completely screened by a high permeability iron yoke. This should considerably reduce the level of external electromagnetic perturbations detected by the coil. The symmetry of the circuit with respect to the horizontal plane helps to improve the uniformity of the flux density in the air gap. The details of the mechanical design and the machining techniques required to realize the necessary small tolerances are under investigation. A simpler magnet is currently installed in the experiment.

• Work has started on a dedicated Josephson voltage standard for the voltage measurements.

Work will continue on the present room-temperature instrument until it has reached its uncertainty limits. The target is to reach an uncertainty below 5 parts in 108 by the end of 2014.

Awards

The NEN (the Netherlands Standardization Institute) and ISO/TC 158 “Analysis of gases” organized the 6th International Gas Analysis Symposium & Exhibition (GAS2011) from 9 to 11 February 2011. Over 220 people attended the symposium which included 60 lectures and 25 exhibitors. The GAS2011 best lecture award was won by Dr Joële Viallon from the BIPM’s

Chemistry Department, with her lecture entitled “Dynamic generation of formaldehyde standards by permeation tubes: performance evaluation using FTIR and cavity ring-down spectroscopy techniques”, given during the session “Metrology, Accreditation & Chemometrics”. The work described validation studies being performed at the BIPM in preparation for the key comparison CCQM-K90 on formaldehyde in nitrogen.

Dr Takashi Usuda, a visiting scientist at the BIPM seconded by the NMIJ, Japan, was awarded the prestigious Ichimura Prize in Technology on 28 April 2011 by the New Technology Development Foundation, Japan, for his contribution to improvement of the National Metrology Standard of Vibration Measurement. The award was in

recognition of his work to develop a laser interferometer for vibration acceleration calibration. The laser interferometer enables high resolution and robust characteristics against vibration noise. Dr Usuda also established the national calibration programme for vibration acceleration in Japan. His achievements improved the Japanese metrology standard of vibration measurement and ensured the traceability of vibration measurements in industry to the national standard.