Étalons métrologiques fondamentaux

Abstract

Fundamental Metrological Standards The International System of Units (SI) adopted by the “Conférence générale des poids et mesures” in 1960 is the outcome of several decades of fruitful research in the setting-up of a consistent system of measurement units. The SI was designed so that in principle, any measurement of a physical or chemical quantity can be expressed as a number in some specified unit. Any quantity can be expressed by a combination of the seven base units of the SI. The definitions of the seven base units are presented with a short description of how they are used in practice. In addition, the particular case of units for ionizing radiation is presented, together with the principle of calibration chains. Mots-clés Étalon de référence, grandeur de base, étalon primaire, Système international d’unités (SI)