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I have a Multimode with the Nanoscope IIIa controller since 1998
So far so good, no problems whatsoever but for the software very limited initially so decided to go for the "new" windows based some yrs ago, lot of money for a computer!! Hard disk got corrupted changed, surprising!
So now the next decision, again a lot of money. I don't know whether this is the right place to put the question, I'll do anyway: right in the mouth of the crocodile!!
otherwise I'll post somewhere else anyway
Did anybody recently decided to change the photodiode with the new one claimed to be low noise?
Is it worthed, any experience?
thanks
stefano
Hi Stefano,
As a "user", I would say that Ben's answer, is pretty much right. The "low noise" laser has a somewhat confusing name...for standard imaging AFM, in cases where laser interference is not an issue, it will not reduce noise. But, when laser lines do appear, they are a real pain, so it will definitely help in these cases, to have it. This is mostly for reflective samples (metals, patterned samples in particular). Quantitative interpretation of force curve where these ripples are present is also much more complicated, as Ben suggested.
If, as you suggest, you have no specific problems with your multimode, it's probably not worth upgrading... I would suggest to.save the money (if you can!) for when something really goes wrong!
Pete.
Don't worry, the crocodiles don't bite!
The low noise head definitely has benefits over the old MultiMode head. But the name could be a little confusing, so it's good that you ask specifically what things are improved.
The low noise heads were developed specifically to reduce the phenomena of laser interference. This was sometimes observed on relatively flat and especially reflective surfaces as a streaking artifact. Laser interference also shows up in force-distance curves as a wavy, periodic noise on the baseline (where the period is ~345nm). The low noise heads reduce these issues tremendously. So they definitely do help produce lower noise images and force curves if laser interference is the problem.
But if laser interference is not a problem for you then the low noise heads probably won't help you. That said, old MultiMode heads do age over time and the laser output can become lower or unstable. So if you've noticed that the performance of your MultiMode has decreased over the years then indeed perhaps a head replacement would help. In some cases old heads can actually be upgraded to the low noise version rather than replaced entirely.
The low noise heads are standard for MultiModes nowadays. In upgrade situations, the low noise heads are considered required for application module electrical modes (CAFM, TUNA, SSRM, SCM) as well as our new Peak Force Tapping based modes (ScanAsyst, PeakForce QNM, PeakForce TUNA). If you do any significant amount of force-distance measurements I would also consider the low noise head to be essential.
Besides the low noise head upgrade, I do have to say that the MultiMode 8 upgrade for existing MultiMode systems is a great deal. It's an extremely cost effective way of extending the useful life of your MultiMode and the new Peak Force Tapping based modes are pretty amazing. We also released a fast scanning accessory for the MultiMode 8 last year. It's worth looking into. You might be surprised to find out what your old MultiMode can do after the MultiMode 8 upgrade.
Best Regards,
-Ben
Bruker MultiMode Product Line Manager
Hi Ben
thanks a lot for exhaustive suggestion
However I thought this to be a user forum, moderated, but users' exchange,by the way is there any blog or forum not "owned" by an AFM producer?
So far I found just:
http://blog.tremily.us/posts/MultiMode/
really helpful and earnest
Of course I understand your answerI was looking for users' experience though
thanks anyway and regards
I'm not aware of any active AFM-focused internet forums that are not sponsored by an AFM company. We do get good user participation here on the NanoScale World though. I really don't see any cause for concern. Though run by Bruker, the discussions here only receive the minimum of moderation to prevent occasional spam-related problems. Users like yourself and Peter are welcome to share your experiences and we hope that it's valuable that you also get to tap into the experience of Bruker experts too. I was a user of our AFMs long before I was a product line manager!