Forums
Bruker Media
Community Media
Bruker AFM Probes
SPM Digest
Application Notes
NanoTheater
Website
中文
Brochures & Datasheets
Publications
Probes Catalog
Events
Manuals & Documentation
Presentations
Guide to AFM Modes
News
Journal Club
Webinars & Video
Nanovations
Other
Hello,
I was wondering if anyone has a solution or knows the reason for the following problem:
I am mounting a triangular shape AFM cantilever(k=0.02 N/m; soft) onto my fluid probe holder and aligning the laser towards the free end tip in air.What i usually get as a sum is around 3.0-4.0V. Soon thereafter, I place a drop of fluid on my cantilever tip to prevent any air bubbles getting stuck within the cantilever's area and then lower/approach my cantilever near my sample with the z motor button,which also lies under a meniscus of fluid.I noticed that once my tip is in fluid, my sum drops down to a maximum of 1.0-1.25 V at the free end tip area but also notice that the cantilever "legs" still give me a higher sum of about 3V.It seems that the fluid has an effect on the reflectivity of my free end tip of my cantilever? This doesn't make sense to me unless I've "bent" that area somehow.
This hasn't happened before, as last week i was getting pretty good reflectivity during previous sessions.Today, however, I tried using three different tips and they all seem to have the same issue.
Cooperation is greatly appreciated!
Alperen Ketene
Hi Alperen,
What kind of tips are you using?
Stefan
Stefan,
I am currently using Olympus TR400PSA triangular cantilevers.( http://www.asylumresearch.com/Probe/TR400PSA,Olympus )There are two tips on each side of the cantilever( k=0.02 and k=0.06). I notice that my 0.06 N/m cantilever seems to give a fine sum all the time.However,recently for all my 0.02 tips(which i've been using in my cell research), the sum is significantly lower,sometimes even zero, when aligning the laser in fluid. By the wa, the only modification on the tips that I've done is the attachment of a glass sphere. The fluid i'm doing all of this in is cell culture medium.
Hi,
The 0.02 N/m lever is quite soft and by attaching a sphere to it you are indeed adding additional weight that will bend the lever downwards. Depending on how straight the lever was to begin with that bending can subsequently cause your signal to go off the detector. Now 1V - 1.5V is not the a tremendously large sum-signal but enough to go into feedback. Make sure that when you align the lever that you do it after the two drops of fluid (the one on the cantilever holder and the one on the sample) are joined. That will mitigate the downward bending of the cantilever to an extend.
You may also want to look into some of our probes. We do offer a 0.02 N/m lever at: http://www.brukerafmprobes.com/p-3445-mlct-exmt-bf1.aspx If you contact bruker probes they will be happy to send you some samples to try out.