Key comparison of 1 kg mass standards linked to CCM.M-K4
Project Description
The results of this key EURAMET comparison of 1 kg mass standards will be linked to CCM.M-K4. BEV procured 12 pieces (2x4+4) mass standards made by Häfner Gewichte GmbH in October 2014. A pair of standards with different density will be circulated. The basic characteristics of the standards (e.g. volume, magnetic properties) and the stability will be measured during 2015. The technical protocol will follow the one used in CCM.M-K4 and will be agreed during the TC-M meeting in 2015. The actual circulation of the standards can be started at the end of 2015 if the stability measurements are satisfying. The project may have up to 4 petals depending on the number of participants so it can be finished in one year. (Note the project was presented and agreed during the TC-M meeting in 2014).
Final Report 2020-02-28
The comparison has been completed and results are published in the KCDB.
Progress Report 2019-01-11
The circulation are finished. Collecting the laboratory results is in progress. First version of draft A report is expecting in April 2019.
Progress Report 2017-04-10
The magnetic and geometrical properties of the procured standards were determined, the determination of the volume and coefficient of thermal expansion was finished in 2015.
The stability of the standards was determined in 2016.
The calculation of the reference value and the linking mechanism was discussed by the Support Group (BEV, DFM, METAS, NPL, PTB). The problem raised by the BIPM amendments to the national standards could not be solved in EURAMET, so the relevant working group of the CCM was asked for a solution.
The project should not be delayed due to the link problems.
The draft of the technical protocol was finalised and was sent out for comments in March 2017 and sent to the CCM for approval in April 2017.
The actual circulation of the standards can be started after the CCM approval and the finalisation of the time table.
Progress Report 2015-04-21
Updates: Linking the results of this comparison to CCM.M-K4 is unusual since it is effected by the receant corrections to the mass values of the national prototypes issued by BIPM. The magnetic and geometrical properties of the procured standards were determined, the determination of the volume and coefficient of thermal expansion is ongoing. Stability will be measured during the year of 2015. The technical protocol will be finalised in June 2015 based on the one used in CCM.M-K4. The actual circulation of the standards can be started at the end of 2015 and the beginning of 2016 if the stability measurements are satisfying.