In the world of metrology, the Physikalisch-Technische Bundesanstalt (PTB), the National Metrology Institute of Germany, is among the top names. For nearly every physical quantity there is at PTB a working group which can measure this quantity with the highest accuracy and thus is able to further develop metrology continually. This applies to the physical base units as well as to all units derived from them. In addition to the numerous calibration services (for measurement tasks which others cannot perform with the required precision), the metrological research and development are, above all, the central points of PTB tasks. Prominent examples are the researches all about the redefinition of many physical base units aimed at here. That which has already been accomplished for the meter, with its trace back to the speed of light in vacuum, is still outstanding for other base units: the coupling to fundamental constants. And thus PTB is working on, for instance, tracing back the kilogram to the Avogadro constant, the ampere to the elementary charge of an electron or the kelvin to the Boltzmann constant. The measurement tasks involved are so complex that only a few institutes at all dare to tackle these tasks. Among these outstanding institutes, international cooperations are then, of course, the rule.
Physikalisch-Technische Bundesanstalt PTB
phone: +49 531 592 8228