In 2011, the 24th General Conference on Weights and Measures sanctioned that the International System of units would be upgraded in terms of internationally agreed values of the Planck, Boltzmann and Avogadro constants and the elementary charge. Experiments based on the watt-balance comparison of mechanical and electrical powers and the counting of silicon atoms came close to determining the kilogram from the Planck-constant value, however an unresolved discrepancy between the two experiments made it impracticable within the 20 μg uncertainty required to ensure continuity to mass metrology.
EMRP project: 'Realisation of the awaited definition of the kilogram - resolving the discrepancies' (SIB03 kNOW) aims to support the redefinition of the kilogram in terms of fundamental physical constants. It will do this by understanding and remedying the error between the European watt-balance determination of the Planck constant and the Avogadro determination.
The kNOW workshop on the kg realisation by measuring the Planck and Avogadro constants (JRP SIB03) will present the background motivating these two experiments and will examine the open problems associated with them. The workshop aims to identify and to achieve a better understanding of the critical aspects and to look at hidden assumptions and phenomena which have not been yet considered. The workshop will feature invited lectures as well as presentations, and participation is open to anyone with an interest in metrology and the precision measurement of fundamental constants. Participants are invited to propose a contribution on any aspect of the watt balance and silicon atom counting experiments.
