Build Your Own Scanning Tunneling Microscope

I don't want to spen writes "For all you fans of nanotech out there, a friend just posted me a link to instructions for building a scanning tunnelling microscope, from the University of Muenster. Interestingly, their licensing terms sound open source-ish to me: '(... We grant everybody the right to construct the microscope using the here-published design for private or educational purposes. On these web pages all necessary diagrams, drawings, material descriptions and software-source-codes are published for free access. While granting the right to build the microscope we make it mandatory that new developments, improvements or other applications of our design are also made openly available for private or educational purposes...)'"

Comments

saw this article a few months back on other sites

[W32.Klez.A]

I work in a plant growth research lab, and we built one of these to get real time images of protoplasts (plant cells in culture). It was cheap, and produces what I found to be suprisingly excellent-quality images. Of course, we also got a hundred thousand dollar Bausch & Lomb scope to do more "complicated" work...

Question to all you bioinformaticians

[mukund]

My question may seem weird due to my ignorance. Is it possible to use such a microscope to find the structure of say.. the HIV virus and its chemical composition? Secondly, how are such small structures located/found due to the huge spatial distances involved?

Re:Question to all you bioinformaticians

[Sci_Fox]

Well, asside from making sure you use vacuum-compatible materials that won't harbor too much gas, it's not that hard to make a vacuum enclosure. I've bought lots of vacuum equipment off eBay, and scavenged old parts from places I've worked.
(sitting 1 meter from a rebuilt Leybold Turbovac PT 50, and other parts)

I recall the ancient SEM at the first place I worked. 1960s equipment. I got okay images after it was cleaned up, and was only drawing vacuum through an old piston-pump. Ex-refridgeration pumps can draw better vacuum than those.

Prions

[Mr Bubble]

Can a tunneling microscope see prions?

Re:I'm just curious...

[femto]

They cannot. It's complete bluff.

Unless they have patents, there is nothing they can do to stop someone from building a microscope using their plans. The only thing they can do is stop you from copying the plans themselves (under copyright law).

John D. Alexander, the inventor of the disk scanner, also has a 'free' STM design on the web. Incidentally, this guy took out a patent on the disk scanner, then withdrew the patent application! Now that's a smart way to make sure others cannot lock up a design with patents (or he just ran out of money).

Re:a free slot for ISA cards

[inode_buddha]

Why couldn't I just use my soundcard line inputs? Not trying to be an asshat here, just reminding people that modems and soundcards basically *are* A/D devices. If you have the $$$ to spend, you can find A/D cards here, they supply pro stuff. Yeah, I'd like to try this under Linux, but I need to ask: does anyone know a good way to re-code the VB into C/C++? This is not the kind of project I normally consider, but its just too damn interesting. Thanks.

Re:open source-ish?

[49152]

Did you bother to read what I wrote? No? didnt think so.

I dont mind that I cannot sell their invention, of course not. But I do mind having to give up for free any improvements I make unless *they too* give up this right.

This is what "Open Source" is all about, freedom of information not "free beer".

Vibration damping

[fermion]

Of course, the most important component for any optical experiment is the Vibration Proof Table(TM)(patent pending). We have several of these using your choice of technology. The cheapest is the Immovable Mass (TM). The downside to this is that it is nearly impossible to ship. Another technique is hanging the apparatus on the Massless String(TM) from a Nearly Immovable Mass(TM). This requires not only an onsite visit by our service technician, but two years advance notice to acquire the material. Finally, we have the Completely Decoupled Environment(TM), in which we put the apparatus in the Perfect Vacuum(TM), and keep it away from all walls with a Leak Free Perfectly Damped Magnetic Field(TM)(patents pending). Unfortunately, though this system is relatively cheap, getting new samples on the 'scope is quite impossible.

We assure you, however, that hanging the scope from a thin scaffolding using light springs, and then attaching the entire setup to a huge piece of granite will not be sufficient.

On a more serious note, an STM is really easy to build, but really hard to make work. There has been more than one physics graduate student that has entered perpetual grad school limbo trying to get one of these to work. The vibration damping is just the start. Learning to etch the tungsten probes so that you get the necessary few atoms at the end is quite an ordeal. And then attaching the probe without allowing the tip to even come close to any surface. And then calibrating the piezoelectric so that the tip will be very very very close to the sample, but never touch it. You will go through 100 hand etched probes before the instrument is even grossly calibrated.

And then measuring the gap current. You learn what kind of noise a power supply really has. Getting a noise low enough so that a signal is discernible after amplification requires a power supply the likes of which few has seen. And then the noise that introduced by the amplification process. This are not your ordinary op amps. I shudder to even think about building a board that quiet.

But have fun, and remember us for you optical table needs. We are, after all, the only one who sell the genuine and otherwise real and purchasable Vibration Proof Table(TM)(patent pending).

Re:Vibration damping

[Compuser]

a. Please tell me you got an F for your efforts
as an undergrad. I say this because the very
essense of tunneling is that it falls of as an
exponential, not as a power law.

b. I assume you were doing STM in air or else
moving a setup downstairs would have taken at
least a week to rebake the vacuum chamber. Now
in air, you have a thin layer of water on the
surface which surprisingly makes it easier to
stabilize a junction.

c. Tips aren't quite some much of a problem, I
agree with that, especially since very good tips
can be bought commercially. And cutting a wire
may work well for metals and semiconductors.
Attaching a probe is usually easy because the
only part you can't touch is the very end.

Responding to original poster:

d. There is no need to calibrate the piezo to be
able to tunnel, that's what a feedback loop is for.
You do have to have an idea of what parameters to
use so it doesn't ring.

e. In fact an ordinary op-amp will do fine and a
clean dc supply from any decent manufacturer
will do the trick. Look at bio and chemistry
literature dealing with patch clamp applications
for good references on more sophisticated designs
but it aint rocket science. The one hard part is
to make sure you put your setup far from any
60 Hz source and have no ground loops or even
no weak grounds anywhere in you setup.

Lastly, the hard part about STM is getting
meaningful data. You typically get junctions that
aren't so good and you need to be able to tell
whether it is the tip or the surface. Generally
to do that you need to do this for a few years and
build up and internal reference for which type
of crappy junction corresponds to which problem.
Then getting a good junction and some data becomes
easier.

This might be handy for...

[core plexus]

...my study of the role bacteria play in geology, and in particular (no pun intended) in the formation of valuable precious metal deposits such as this: Alaska Bugs Sweat Gold Nuggets

If nothing else, it might be cool to build one just to look at stuff, and I finally have a use for that ISA slot.

-cp-

President Bush to Liberate Alaska!

Re:More STM info

[Compuser]

Beetle design, also known for its creator as the
Besocke design is not unique in allowing full
3D approach positioning. It does have many advantages
like farly good rigidity, thermal compensation and
ease of assembly.
There are designs which are even better than
slipstick, such as the good old inchworm design
and its offshoots, especially ones designed for
low temperature operation (some are patented).
Even slip-stick isn't limited to beetles. Another
design was patented early on by Lyding and is also
thermally compensated, though harder to build than
Besocke stuff.
Bottom line, look around. There is no shortage of
really cool designs to fit any need.

Re:I'm just curious...

[johannesg]

If you withdraw, does that mean you get a refund? If so, this is a great way for geeks everywhere to completely swamp the patent system with useless software patents, while at the same time slowly but surely protecting O.S. in a protective layer of "withdrawn" patents. All without costing a cent.

Get ready to patent everything from pointers to linked lists to schedulers to drawing algorithms... (and before you mention there is prior art, that's not stopping anyone else now is it?)