Technique for Measuring the Tiniest Forces

When chemists want to measure the bonding forces in molecules or other most minuscule forces very accurately, they have to calibrate their measuring instruments (for example the cantilevers, i.e. the measuring tips, of scanning force microscopes). And if it is a matter of comparing the attained results with other results, one must refer to a common basis.

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).

Tell Us What You Think

Do you have a review, update or anything you would like to add to this news story?

Leave your feedback
Your comment type
Submit

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.