Some of you may be familiar with my rant about how this guy stumbled upon the brilliant idea of using thermoelectric cooling and built it before I did, receiving internet credit points for the idea. I am not going to repeat my rant here, instead I give the person mad props for thinking of the idea, and then finding the time to actually make it. If it wasn't for ASS I would have probably also made one by now. But now with the end of ASS in sight, I am beginning to assimilate parts for my next project, the Decay-o-scope.
Cloud chambers are really neat, and since I am into nuclear stuff, I decided a while back to build one, eventually... Then I learned all about Peltier coolers while working at ERG, and had the great idea of using the thermoelectric devices in a solid state cloud chamber! Most of the time cloud chambers are built using dry ice, or some kind of refrigerant system. Using a solid state device would dramatically increase convenience, and portability. Not only that, but the coolness factor goes up by orders of magnitude.
I have a far off plan of eventually building some kind of furniture (coffee table?) around such a solid state cloud chamber (SSCC). To start with though, I want to build a proof of concept. Since Rich beat me to it, I figure I can build my own version, with some extra stuff (and extra size!).
First off, there are a couple of things about cloud chambers, apart from the cooling, that make them sort of hard to use. Unless you have a really nice chamber, seeing the actual trails can be difficult. I hit on the idea of using a nice fresnel lens for the viewing plane. It would magnify the interior of the chamber, allowing a viewer to more easily see the trails inside. Not only that, but fresnel lens are cheap, and can cover a large viewing plane, when compared to conventional convex lens.
So I hopped onto ebay and did a quick search for Fresnel lens. Of course I found some immediately, and as I hoped, they were nice and cheap. But that's not what excited me. Check this one out. See anything interesting there? It's a fresnel lens from a 3M overhead projector!
An overhead projector has all the optics, cooling fans (for the junction heatsinks), and plenty of space to house the chamber, the powersupply, junctions, etc. The viewing optics are perfect for this application too! The overhead lenses provide a great way to get really close with the trails, and the fresnel lens embedded in the top of the projector is nice an large, perfect for a big chamber. Also, overhead projectors are super portable, as most of them are found on carts.
Sometime soon I will be putting together an extremely small version of this cloud chamber, as the initial proof of concept. The parts are on the way, and as soon as ASS is complete I'll be digging into the Decay-o-scope.