A Web-based database for the international programme to improve the Avogadro constant along the silicon route

A number of measurement institutes are working together toward a determination of the Avogadro constant with a relative combined standard uncertainty of 10^-8. This will enable a definition of the kilogram based on the mass of a specific number of ¹²C atoms rather than an artefact. In order to bring together all the data obtained in the various laboratories and maintain accountability and traceability across the collaborating institutes, a Web-based database has been set up. This database forms part of the BIPM website, although access is currently limited to project participants. Any data used in publications on the Si-route, together with supporting evidence, can be found in this database.