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Hy everyone,
We have just install a new bioscope catalyst in the lab. Everything seems to be right execpt for the calibration of cantilever in liquid (in air everything is ok). Anyone has an experience of calibartion in liquid on the catalyst?
The problem seems to come from the determination of the deflection sensitivity, calculated value are very strange (off course, we don't have any experience on the catalyst, but we apply the same procedure than on the multimode V, where it works great!). I will be happy to have a return of users about the use of thermal tune in liquids on the catalyst
Hi Guillaume,
What range of deflection sensitivities are you measuring in fluid? They will vary somewhat from the values measured in air, but not by a lot.
The most common issue calibrating cantilevers in fluid is that the resonant frequency shifts to much lower frequencies and the peak becomes much wider. For soft cantilevers, the peak will extend all the way down to DC (0 Hz) on the PSD graph shown in the thermal tune view. We do truncate the low frequency end of the curve so that the higher noise there (1/f noise and environmental) doesn't skew the display and results. This makes it important to position the markers correctly for the curve fitting step and then move them for the final calculation step. But before we get to that point, let's be sure that you are getting the right deflection sensitivity because of course that is critical.
It would be helpful to see some screenshots to help identify the problem. A screenshot of a force curve showing the position of the markers you use to calibrate the deflection sensitivity would help. Then two screenshots of the thermal tune view, one showing the curve fit marker positions and one showing the marker positions for the final calculation. You can email these to me at bohler(at)veeco.com or post them here.
Regards,
-Ben
Hi ben,
thanks for your answer,
Concerning the problem to calibrate soft cantilever in liquid, we know about it but we don't want to do it in air as we only work in liquid. We used MSCT cantilever and especially the softer one (0.01N/m), and on the multimode we enlarge the frequency range to access to the peak and we do the same on the catalyst but as i previoulsy said it, we never succeed to have a valuable spring constant. In my opinion, due to wrong deflection sensitivity (I'lle send you screenshots this week) and maybe because the catalyst is more sensitive to the noise than the multimode.
Regards
Guillaume