Help in imaging using SNL probe in liquid tapping mode on diInnova AFM

Hari posted on Mon, Sep 30 2013 4:33 PM

rated by 0 users

Hello,

I am currently trying to test a diInnova AFM in imaging DNA deposited on mica in liquid tapping mode. In past I have done 'tapping in liquid' mode imaging of DNA and DNA bases structures using old Nanoscope IV system with SNL tips several times successfully. I usually use the 'small-thin' tip for such imaging. For the Nanoscope IV system I remember that while auto-tuning to find the resonant frequency for the SNL tip, I used to set a target amplitude of around 0.5 V. But reading different post here, particularly this following one, http://nanoscaleworld.bruker-axs.com/nanoscaleworld/forums/p/673/1503.aspx

I see that target free amplitude and other parameters can be very different for Innova series of machines. Could someone please advice me on the parameters that I should aim for in case of diInnova machine, like the target amplitude, resonant frequency, gains, etc. (I am not sure how different Innova machines are from diInnova).

I also have another question related to liquid imaging on diInnova. I am having hard time centering the laser properly on the QPD. I first load the cartridge-microcell-chip setup with a hanging liquid drop, on the sample. Then using optics I align the laser to the end of desired tip and then proceed to center the laser on the QPD with the help of the laser alignment display and the mirror adjustments. But in I find it almost impossible to center the laser spot to the center of the crosshairs and the maximum I am able get is around 0.6 V. When I image using the same AFM in 'tapping in air' mode I do not have any problem in laser centering and I get good images out. In liquid mode, so far I have not been able successfully able get any images. I would appreciate any advice you might have regarding this.

Thanks in advance !

- Hari