Default value of Peak Force Amplitude is 150 nm. Why this value has been selected and can it be changed in some cases?

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BrukerApplications replied on Tue, Jan 19 2010 6:52 PM

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150nm Peak Force Amplitude equals 300nm peak to peak of Z piezo modulation and it is large enough to pull the probe away from the most samples. For very sticky or rough sample or dull probe, larger Peak Force Amplitude is needed. But too large Peak Force Amplitude can excite nonlinear oscillation in the Z piezo and generate loud acoustic noise.

In liquid, large Peak Force Amplitude can introduce large parasitic background due to the hydrodynamic force in fluid. It is generally desired to use smaller Peak Force Amplitude as long as the tip is still able to pull away from the sample