Dr Rudolf Thalmann
Federal Institute of Metrology METAS


Traceability of nano-scale measurements to the international system of units SI


Traceability of physical measurements to recognized realizations of units is a prerequisite for comparability of measurement results. The international systems of units will undergo a major revision by the 20th of May 2019, when all units will be based on fundamental or natural constants. For instance, the mass unit can be derived from a fixed value of the Planck constant using a Watt balance or by counting atoms with an x-ray interferometer.
The length unit meter, which is defined by fixing the value of the speed of light, is realized with lasers, whose optical frequency is derived from atomic clocks with the help of femto second frequency combs. For nano-scale measurements, a recognized way for getting traceability is based on an internationally agreed value of the Si lattice constant.
In a second part of the talk, activities of the micro- and nano-metrology laboratory at METAS shall be presented, including atomic force microscopy, micro-coordinate metrology, micro computed tomography and photo mask measurements. As an example, it will be shown, how traceability to nano particle standards can be provided.


Ruedi Thalmann graduated in Experimental Physics at ETH Zürich. In 1986 he received his PhD at the Institute of Microtechnology, University of Neuchâtel in the group of Prof. René Dändliker for his work in the field of coherent optical metrology. After a postdoc in optical computing he joined METAS, the Swiss National Metrology Institute, where he is head of the sector Length, Optics and Time. His research interests are in the field dimensional metrology.