In the case of scanning force microscopes, the nominal values for bending stiffnesses deviate distinctly from the actual values. With the current devices, calibrations of cantilevers are accurate to > 5%.
For forces in the nano- and piconewton range one therefore requires more accurate realisations and stable transfer standards.
In order to offer this in future, the Physikalisch-Technische Bundesanstalt (PTB) has set up the protoype of a nanonewton force-measuring device. First measurements show that the measuring principle functions well: The very small force (of approx. 50 pN) of a laser beam on the pendulum, the "heart" of the apparatus, is measured with a voltage (acting as counterforce), and this with a measuring uncertainty of 5 % to 10 %.
First measurements have shown that the measuring device is sufficiently protected against vibrations (so-called "seismic noise"). A large-scale device, which is to be set up next year, is envisaged to bring still further improvements here. Furthermore, other changes are also needed to be able to actually measure on cantilevers (as transfer standards).
Erika Schow | alfa
First direct observation and measurement of ultra-fast moving vortices in superconductors
20.07.2017 | The Hebrew University of Jerusalem
Manipulating Electron Spins Without Loss of Information
19.07.2017 | Universität Basel
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
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Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision
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