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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...)'"
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.
How we know is more important than what we know.
I dont think so
;-)
With BSD or GPL style licenses you are actually allowed to use the copyrighted work in an commercial setting, just not to sell it. For instance a commercial company might run their web server using GPL licensed software.
With this not only do they retain the exclusive commercial rights, but the license might in fact be read as an attempt to force you to turn over any improvements on their design.
So if you make an improvement, does this mean that you have implicitely granted the University of Muenster the rights for commercial exploitation of your own improvment by accepting their license in the first place?
This does not sound "open source-ish" to me, it sounds like out right theft.
PS: Please ignore any bad spellings/grammar in my english or at least be polite when telling me
I am not aware of any of any instance of a large molecule whose structure was deduced from a scanning tunneling microscope. Things like proteins, enzymes, and viral particles are most generally probed by growing them into crystals and a analyzing their x-ray diffraction patterns. The big problem with this technique is that big molecules are hard o grow into crystals (thus all the grow protein crystals in the micro gravity of orbit effort) Nonetheless, a Scanning tunneling microscope is VERY COOL, and within the engineering capabilities of a dedicated hobbyist. Heck, you can now buy a complete Scanning tunneling microscopes for 20K; pretty cheap for a high-end piece of laboratory equipment. The real trick is to get the stage into a hard vacuum at cryogenic temperatures. Who will be the first person to spell out LINUX in Xenon atoms on a nickel substrate? I will donate money to that cause By the way, in college I used to produce atomically sharp needles for field emission ion sources just by burning tungsten wire in a propane torch. That should be an easy way to make probe tips
The design as given requires a ISA slot because of the type A/D converter card they selected. If you do not have an ISA slot available, I am sure a PCI based, or even a USB based analog to digital converter can be found. It would probably be a good idea to change the A/D, as the one used has a 100khz refresh rate. I am sure that there are cards out there that refresh at a much quicker rate, thereby allowing improvements in other areas of the design. Just be aware that the software would have to be modified because of the different card, but that should not be a difficult matter for anyone attempting this project.
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The GPL only kicks in when you *distribute* copies of the software. In this case if you choose to ignore the GPL, copyright law defaults to 'you are not allowed to distribute the software'. Hence the *only* legal way to distribute (note: I didn't say 'use') GPL'd software is to agree to the GPL.
There is a similar reasonably well-documented homebrew STM that was built by a guy named Jurgen Muller. His site is pretty interesting, and well worth the read.
Obviously there are a lot of articles on STMs in various academic journals. If you're at a university, you might start by searching in Reviews of Scientific Instruments and perhaps the Phys Rev journals.
I was involved with a STM project for a while, and our conclusion was that the 3D piezo setup is quite fragile, and extremely difficult to isolate from vibration, etc. It seemed that a better design was a so-called slip-stick walker, which uses a stage that slides on smooth rails. A tube of piezoelectric ceramic is attached and driven in such a way that it creates a series of small, sharp forces on the stage that momentarily break the static friction between the stage and base, causing it to move in small steps.
This stage is used to approach the sample to the STM tip, which is mounted on another piezo tube, and can be deflected laterally and vertically in order to do a raster scan of a small area of the surface.
The limitation to this method is that you can't scan a very large surface area. You can add a second "walker" unit underneath the first one so that you can move the sample from side to side in addition to moving it towards/away from the tip, so this would allow you to scan a stripe across the surface.
To get full 3D control, there are several designs called "beetles" (IIRC) that are described in the literature, which use a somewhat similar technique that allows more control.
Maybe you should read it a little closer. This is a summer project for rich and technically competent high schoolers, or grad students. This is not cheap. And when it comes to making tips I think it's great to have kids playing with tubs of KOH.
And it's not SEM, it's STM. Sem is great for making pictures of insects and what not, STM is great for tracing out the p-orbitals of graphite. BIG difference (not your error, but as long as I'm clarifing, why not hit that too).
Propose a sputtering chamer or a PVD chamber, they'd probably be much cheaper to build and can be used to make other stuff. Which then one could look at with either an SEM or STM if one chose.
Goto industrial and university auctions too. I've hear tell of people giving TEM's away to whomever was willing to transport them (not that an isolation pad on which to set it is within the means of Young Scientists). But still.