CCEM

1. CCEM Comité Consultatif d’ Électricité et Magnétisme Report of the President to the 22nd CGPM Ernst O. Göbel PTB Braunschweig and Berlin, Germany

2. CCEM Structure of the CCEM E. O. Göbel, PTB, President T. J. Witt, BIPM, Executive Secretary 22 members + director of the BIPM, 4 observers Four working groups: • Working Group on Electrical Methods to Monitor the Stability of the Kilogram / Chairman: I. Robinson, NPL • Working Group on AC Measurements of the Quantized Hall Resistance Chairman: E. Braun, PTB (until Sept. 2002); J. Melcher, PTB (since Sept. 2002) • Working Group on Key Comparisons (until Sept. 2002); Working Group on Low Frequencey Quantities (since Sept. 2002) Chairman: H. Bachmair, PTB • Working Group on Radiofrequency Quantities Chairman: L. Erard, BNM (until Sept. 2002), J. P. Randa, NIST (since Sept. 2002)

3. CCEM Meetings: CCEM Sept. 2000, BIPM Sept. 2002, BIPM WG: Key Comparisons Sept. 2000, BIPM now: WG: Low Frequency June 2001, BIPM Quantities Sept. 2002, BIPM WG: Radiofrequency Quantities Sept. 2000, BIPM June 2001, BIPM Sept. 2002, BIPM WG: Monitoring the Stability May 2000, Sydney of the Kilogram June 2002, Ottawa July 2003, Paris WG: AC Measurements of the QHE May 2000, Sidney Sept. 2000, BIPM June 2002, Ottawa Sept. 2002, BIPM

4. CCEM STATUS OF LEAST-SQUARES ADJUSTMENT OF FUNDAMENTAL CONSTANTS

5. CCEM Fundamental Constants:

6. CCEM KJ-90 ; RK-90 • KJ-90 and RK-90 remain comfortably coherent with the most recent (1998) CODATA values (however the 2002 KJ value might differ slightly when the new value for the Avogadro constant is included) • The relative standard uncertainty assigned to RK has been reduced by a factor of 2 to 1 x 10-7 (CIPM approved in 2000); i.e. the representation of the Ohm using the QHE and RK-90 agrees with the SI-Ohm within 1x10-7 with a reproducibility which is much better (~10-9)

7. CCEM QHE - Key Comparisons

8. CCEM Revised Technical Guidelines for Reliable Measurements of the Quantized Hall Resistance F. Delahaye, BIPM, and B. Jeckelmann, METAS Metrologia, to be published www.bipm.org

9. CCEM ELECTRICAL METHODS TO MONITOR THE STABILITY OF THE INTERNATIONAL PROTOTYPEOF THE KILOGRAM Required for Monitoring the Stability of the Kilogram: s < 10-8 !

10. CCEM Watt balance (Planck constant) NPL in operation after considerable reconstruction. Target uncertainty < 3 parts in 108 in 2004 NIST in test operation after complete reconstruction. Operation in vacuum, electromagnetically shielded environment, new support system, incorporation of programmable Josephson system. Daily runs show typical standard deviation of about 0.06 W/W. Target uncertainty  1 in 108

11. CCEM Watt balance (contd.) METAS in test operation (100 g mass); different construction; A new magnet will be mounted by the end of 2003. BNM design phase completed; under construction. BIPM design phase.

12. CCEM Mass levitation (flux quantum) NMIJ/AIST: achieved relative uncertainty: 1x10-6, basic studies (precision trajectory measurement, trapped magnetic flux etc.) VNIIM/ MIKES: Nb films on monocrystalline sapphire films; superconducting levitation frame weighing 100 g

13. CCEM Avogadro co-operation Determination of the Avogadro constant using Silicon Single Crystals BIPM PTB IMGC NMIJ CSIRO NIST NPL IRMM Achieved rel. uncertainty: 1.7 x 10-7, however:

14. CCEM NA = 6.022 135 53 (103) x 1023/mol Comparison of the Avogadro constant

15. CCEM • SET: • Single Electron • Tunneling Devices • for Metrological • Applications • current • capacitance • temperature • photons on • demand

16. CCEM COUNT Counting Electrons One by One:Measurement of Very Small Electrical Currents 2000 - 2001 - 2002 A research project supported by the European Commissionunder Framework Programme 5(Contract No. G6RD-CT 1999-00046)

17. CCEM COUNT • Instrumentation for precise generation • of small currents based on SET pumps; • Aim: 1x10-6 for current of a few pA • Instrumentation for measurement of small • currents based on SET counter; • Aim: 1x10-5 for a current of a few pA Achieved: 3.2 pA with  = 4x 10-6 (type A)

18. N U C CCEM Capacitance Standard Capacitance standard, based on the quantization of electrical charge Example with numbers: C = 1 pF, N = 108 Þ U »16 V NIST (1992) Relevant for metrology if the relative uncertainty becomes better than 10 -7 ! „Measuring the electron´s charge and the fine-structure constant by counting the electrons on a capacitor“,Williams et al., J. Res. Nat. Inst. Stand. Technol.97, 299 (1992)

19. CCEM Capacitance Standard (contd.) • NIST 1996: This experiment is feasible with a relative uncertainty of 10 - 8 NIST 1999: First measurement of a cryo-cap´s capacitance by using the SET method„A capacitance standard based on counting electrons“, M. W. Keller et al., Science 285, 1706 (1999) • NIST 2003:Reproducibility (s)= 1  10 -7 • Total uncertainty (C)  1 10 -6 • Ccryo-cap 10 pF compared to a calc. capacitor • 7 junction SET pump (error rate  10-8) • SET electrometer (null detector; sensitivity 10-3 · e)

20. CCEM Alternatives: A)Si based SETTs (NIST) smaller charge offset; parallel integration B) Single Cooper Pair Tunneling (SCPT) Devices(NIST, PTB) C) Single Electron Transport by Surface Acoustic Waves (SETSAW) (NPL, Univ. Cambridge, PTB) B) and C): higher operation frequency

21. 0 -3 -6 8.5 9.0 9.5 CCEM AC Measurement of the QHE BIPM, NRC, METAS, PTB, NML, IEN, NIST Specially designed samples and multiple series connection   1 x 10-7

22. CCEM

23. CCEM 1V Programmable Standard NIST • Programmable from • +1.1 V to -1.1 V • 1 s settling time • Output Step Height = • 2 to 4 mA

24. CCEM Josephson Arbitrary Waveform Synthesizer (JAWS) (supported by the EC) JAWS homepage Participants www.jaws-project.nl

25. CCEM JAWS AC voltage standard for arbitrary waves based on Josephson Arbitrary Waveform Synthesiser Objectives: f = 1 Hz - 10 kHz U0 = 10 mV  < 10-4

26. CCEM CCEM Key Comparison and Calibration and Measurement Capabilities 102 CIPM and RMO Key Comparisons (total 516) recorded in KCDB 17 completed (total 103) 9094 CMC entries (total 15830)

27. CCEM indeed is very active! Thanks for your attention!