Working Group Members

CCM Task Group on the Phases for the Dissemination of the kilogram following redefinition (CCM-TGPfD-kg)


Dr Stuart Davidson

National Physical Laboratory

United Kingdom

List of meetings

Meetings and related documents

Past Meeting

  • 12
  • July
  • 2023

Past Meeting

  • 24
  • May
  • 2023

Past Meeting

  • 21
  • April
  • 2023

Past Meeting

  • 03
  • October
  • 2022


Terms of reference

The dissemination of the kilogram after 20 May 2019 is taking place in three consecutive phases:

  • Traceability to the IPK (but taking into account the additional uncertainty coming from the new definition) (May 2019 to February 2021),
  • Dissemination of the consensus value (from February 2021),
  • Dissemination of individual realizations (in the future).

Based on "the mise en pratique of the definition of the kilogram" and on "the CCM short note on the dissemination process after the proposed redefinition of the kilogram" the task group will:

  • Ensure the correct implementation of the present traceability across the period of the redefinition of the kilogram,
  • Propose a detailed calculation of the consensus value and its uncertainty and oversee the transition for the "present traceability" to the use of the consensus value,
  • Propose methods to maintain the best possible stability of the consensus value over time (including comparison periodicity),
  • Propose clear criteria for moving from the consensus value dissemination phase to the individual realization dissemination phase,
  • Maintain a detailed document describing the three dissemination phases for the CCM and the mass community. This document includes the calculation of the consensus value, its uncertainty and time scale as well as any other relevant information related to the dissemination of the kilogram,
  • Provide advice to the CCM-WGM in all questions regarding traceability of the kilogram during the first two phases above.

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