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Hi Jerome, Please see the other post as Joop notes. It seems that you are not the only one that has lost their calibration lately. The two different ETRs are calculated at different distances from the tip apex (there are parameters in the analysis view, so you can control the distances). You should figure...
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Hi Scott, Did you recently upgrade your software or system? The thermal tune gains are stored in a file called "system.par". If you have not changed hardware, you may be able to snag the correct calibration values out of the old system.par file found in the directory with the z.exe file (usually...
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Every time you put in a new probe or change the laser spot alignment or change from air to fluid, you must recalibrate the deflection sensitivity. For instructions on how to calibrate, please refer to the manual. The calibration must be done with a sample that is very stiff compared to the cantilever...
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That is generally due to poor deflection sensitivity calibration. If the deflection sensitivity is too large, the change in cantilever bending can be erroneously calculated to be larger than the Z piezo motion. This causes the deformation calculation to return negative numbers and will cause problems...
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Those probes are a bit stiff for the thermal technique. I would suggest the "Sader Method" as an alternate option that might give more accurate results: http://www.ampc.ms.unimelb.edu.au/afm/calibration.html This document describes the options for spring constant calibration and the advantages...
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Deflection sensitivity depends on: The shape of the laser spot when it hits the PSD (how does the response change as a function of spot position) The length of the cantilever and how it bends along its length (since we are using an optical lever, this determines how much the spot moves) The geometry...
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Dalia, As you correctly state, the accuracy of the thermal-tune method decreases as cantilevers become stiffer. This happens because the thermal motion decreases (kz^2/2=kbT/2) with increasing k, to the point where the motion falls below the sensitivity of the detector. This obviously happens first in...
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Ash, There are many good references on calibration, here is one from Ben Ohler: AN094-RevA0-Practical_Advice_on_the_Determination_of_Cantilever_Spring_Constants-AppNote.pdf In general, the thermal tune calibration method takes into consideration the tip location because the method uses the measured deflection...
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The key is to get the calibration parms for the measurement conditions. If the coating will not effect the spring constant or tip end radius, you can do the calibration of those parms prior to coating. You cannot pre calibrate the deflection sensitivity since that depends on the laser alignment. In fact...
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Just learned about this product from Photonic Cleaning Technology today ( http://www.photoniccleaning.com/ ) Natalia cleaned this very dirty grating in about 15min. Optical images below: Before: After: