Host: The Japan Society of Vacuum and Surface Science
The National Metrology Institute of Japan (NMIJ) and some other foreign research institutes succeeded in measuring the number of atoms in a 1 kg sphere made of 28Si-enriched crystal using the X-ray crystal density method with an uncertainty better than the long-term stability of the international prototype of the kilogram. In November 2018, it was adopted under the Metre convention to change the definition of the kilogram using our data. In this talk, the measurement technologies contributed for the new definition of the kilogram are introduced, and new measurement technologies to be introduced by the new definition are overviewed.
