SI traceability: Current status and future trends for forces below 10 microNewtons

Measurements related to nano- and micro-scale science, technology, and manufacturing are pushing the limits of detectable mechanical, electrical, and chemical quantities to ever smaller values, raising questions about traceability on such scales. The case in small force measurement is illustrative. At present, the mechanical unit of force is linked to the International Prototype Kilogram, or a deadweight force of nearly 10 N. Although known with exquisite accuracy on this scale, such a mass-based force standard is of little use to investigators and manufacturers using instruments that can determine quantities twelve orders of magnitude smaller. Recognizing this situation, the world congress of the International Measurement Confederation (IMEKO) convened a round table of researchers from National Metrology Institutes representing the US, Europe, and Asia to provide an overview of the emerging field of low-force metrology. This paper captures the information shared in that round table and amplifies on its content.