In view of the proposed redefinition of the kilogram, in 2005, 2007 and 2010 the CCM adopted recommendations and conditions to be met before the redefinition is implemented. Some of these conditions concern the uncertainty by which the kilogram will be realized after the redefinition. This uncertainty has become a point of discussion in other committees, because the needs for this value were not sufficiently transparent. Here, examples of the realization of the new kilogram with different uncertainties, along with the experimental results available from the Avogadro and watt balance experiments, the uncertainties of mass determinations and their propagation with reasonable assumptions are presented, in order to compare possible realization uncertainties with the requirements in practice. It turned out that the CCM conditions are reasonable, if major changes in the dissemination chain of the kilogram are to be avoided.
A Faraday cup with 37 segments has been developed to measure the two-dimensional current distribution I=f(x,y) and the total beam current of an ion beam. With an overall cross-sectional area of about 3420 mm2, reproducible current measurements can be carried out down to some nanoamperes. The Faraday cup is used to measure ion beams in an energy range up to 25 keV and beam currents up to 10 mA. The current is determined on the basis of the voltage drop at selected metal film resistors. Initial results confirm good practical applicability in the analysis and adjustment of ion beams.
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