The kilogram redefinition—an interim solution

The role of measurements of the fundamental constants continues to be extremely valuable in underpinning the basic units of metrology. It is concluded that it might be preferable to sustain the present definition of the kilogram for an interim period by having a mise en pratique accompanying the definition, much as is currently done with the specified methods of realizing the metre. Central to this proposal is our view that there is considerable latitude in the interpretation of the present definition of the kilogram and that this can be exploited while always disseminating a consistent mass unit. This would also permit the present methods of maintaining and disseminating the kilogram to continue to be employed throughout the world where necessary at the present accuracy until the new technology could be phased in. An alternative definition of the kilogram, formulated in terms of frequency, is also introduced. This would give an ampere that fundamentally depends on the elementary charge, e, without the need to change the present definitions of the ampere and ohm.[PUBLICATION ABSTRACT]