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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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Abstract Uncertainty in cantilever spring constants is a critical issue in atomic force microscopy (AFM) force measurements. Though numerous methods exist for calibrating cantilever spring constants, the accuracy of these methods can be limited by both the physical models themselves as well as uncertainties...
Posted to
Publications
by
Ben Ohler
on Wed, Apr 28 2010
Filed under: spring constant, NanoScope V, thermal tune, calibration
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Diminshing feature size, combined with requirements for higher throughput during quality control, have steadily increased demand for Critical Dimension Atomic Force Microscopy (CD AFM). In contrast to Scanning Electron Microscopy (SEM), the CD AFM provides a solution for nondestructive and rapid 3-dimensional...
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Atomic force microscopy (AFM) is being used in a great variety of force measurement applications, including investigating the unfolding pathways of native membrane proteins, probing the structure of single polysaccharide molecules, and monitoring the response of living cells to biochemical stimuli. All...