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

Re:Question to all you bioinformaticians

[QuantumG]

no. To find the 3d structure of a protein or a virus you need to be able to crystalize it and then use a technique such as xray crystalography or NMR. There are some new techniques being developed based on mass spectography that can determine the structure of proteins that cannot be crystalized, but they're in their infancy. An STM simply can't be used, because the sample must be able to conduct a current (ie, it has to be a metal or something placed on top of a metal). Preparing samples for an STM is much like preparing samples for an electron microscope, you need to infuse the sample with a conductive material (usually gold) to be able to see it clearly.

Atomic force microsopes on the other hand can do some very neat work with small organic particals, but seperating something like an HIV from solution is still difficult, and usually involved crystalization.

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).