On the path to a “nanometer standard” | PTB.de

Absolute measurement of the thermal expansion and compressibility of single-crystal silicon

Gauge block made of single-crystal silicon. Dimensions: 197 mm × 35 mm × 9 mm. Credit: PTB

PTBnews 3.2021 — At PTB, absolute length measurements on a single-crystal silicon gauge block have been performed using imaging interferometry. These measurements have a smaller measurement uncertainty than all previous measurements. They provide more accurate values for the CODATA reference data and are valuable for a new secondary realization of the meter.

Source: On the path to a “nanometer standard” – PTB.de