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[quote user="meaton212"] How do you run the HSDC at the resonance frequency? According to the manual, it says Amplitude monitoring occurs at 500kHz. How do you adjust this? Also, how do you switch off the drive frequency in the middle of a capture? [/quote] The amplitude channel responds too slowly for this measurement - it is best to do it
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For your two examples of different deflection sensitivity with the same probe, did you change the laser alignment between the measurements? It is normal for the deflection sensitivity to change if the alignment is changed, even with the same probe. If the alignment did not change, there is a problem somewhere. In your screen grabs, you are plotting
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You are correct - the drive amplitude is not the quantity you are interested in. If you are tuning manually you can get the free amplitude by reading off the amplitude of the cantilever response (the blue curve on the upper graph in the tune window) at your chosen drive frequency (the position along the frequency axis that you set the "offset"
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Hi Alessandro, the old SAM works fine with a Multimode 8 and NSV. We have a system where we use the same combination. Best wishes, Nic
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Hi Deepak, the lateral photodiode signal can usually be accessed from the "output" BNC terminal of the Aux A channel on the SAM in both contact and tapping mode on NS3a instruments, if the SAM is connected between the extender module and the AFM. I have not tested if this is still the case if the SAM is connected between the extender and controller
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I believe that the units used just reflect that the signal is a voltage (i.e. the microscope software is reporting the voltage measured at the ADC). Strictly speaking, the deflection should be a dimensionless quantity (as your logic shows) but the signal is still a signal - if it wasn't represented by a physical quantity, the microscope wouldn't
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Hi John, the vertical deflection is ((A+B) - (C+D))/SUM, and the lateral deflection is ((A+C)-(B+D))/SUM, where A, B, C and D are the signals from the quadrants on the photodiode and SUM is A+B+C+D. Looking at the above equations, you can trick the microscope into thinking that a lateral deflection is a vertical one by swapping the B and C photodiode
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Check the "minimum engage gain" setting in the "other controls" panel - I believe the contact mode engage uses whichever is higher out of the integral gain set in the feedback panel or the minimum engage gain, so it may be that your minimum engage gain is set too high and causing oscillation of the Z piezo.
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Hi Celine, the sample you linked to is usually used for scanner calibration, as opposed to cantilever calibration, so I don't think it would be a good choice. The standard that is typically used for the Varenberg wedge method is the TGF11 grating from Mikromasch. I can't see it on the Mikromasch website anymore, but it appears to be available
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I'm afraid it's difficult to do with any AFM. A good and relatively recent review can be found here: http://iopscience.iop.org/0022-3727/43/6/063001 Good luck, Nic