6. Performance

6.1 Stability of the metrological chain

The first results presented enable us to assess the stability of the mAFM metrological chain. These data are very important, as they represent the ultimate limit that the instrument's positional stability can reach when performing closed-loop measurements. When working in open loop, the instrument is subject to drift. These drifts are caused, for example, by mechanical expansion of the assembly, or by drift of the piezoelectric actuators. Even if these drifts are present, they are for the most part measured by the metrological chain, which means that when the instrument is operating in a closed loop, they can be compensated for. However, this compensation has its limits. Drifts in the metrological chain are not measured, so cannot be corrected...