The feasibility of a watt balance based on twin pressure balances

In previous work at MSL, the concept of a watt balance based on twin pressure balances was proposed both for a measurement of the Planck constant and for a non-artefact realisation of the kilogram. Here, further developments of the concept are described including a novel magnet system suitable for use in a pressure balance based watt balance. The feasibility of such a watt balance achieving an accuracy (relative standard uncertainty) of about 2 parts in 108 is considered, focusing mainly on alignment and pressure balance performance characteristics.