Building a Cloud Chamber: Tips and Tricks

[Quantum_Grid]

http://www.lns.cornell.edu/~adf4/cloud.html"

Has anyone tried this? It looks really cool, and I am thinking about giving it a shot, but I'd like to know how easy it is to get it working, or if there are any other things I should know.

One thing I am concerned about is the directions say to use a "metal sheet" but doesn't specify what kind of metal. I don't know if it would make a difference, but I am curious, and I would really like to try this out.

Thanks for the help!

 

[negitron]

Doesn't matter as long as it's a good thermal conductor (which most metals are).

 

[Quantum_Grid]

Doesn't some metal react with dry ice though?

 

[negitron]

Not really. Dry ice is just frozen CO₂, which is relatively chemically inert.

 

[Creator]

Pretty cool; It is somewhat amazing that you can access particle physics, even muon decay, with such simple apparatus.

I wonder if you could determine the particle energy in some way; like for example, set up a strong magnetic field through the entire device. Use a known beta source to calibrate the energy of curvature...and then measure the deflection of the incoming.

I suspect with a video or CCD camera you could get a good idea of the cosmic ray flux in your area.


...

 

[Quantum_Grid]

I know that, in fact, you can apply a vertical magnetic field in order to deflect the charged particles. By the direction of the curve, you can tell if it's positively or negatively charged, and you can calculate it's momentum as well. I am pretty sure that even modern particle detectors use a magnetic field in the same way to detect charge and momentum.

I wonder if it's as simple as putting two powerful magents outside of your cloud chamber.

 

[Creator]

Yes, it could probably be done , but you would have to calibrate it with a known radioactive source, say, a beta source..

The B field production would need to be strong enough to be homogenous as possible throughout, and also the coil or magnet needs to stay clear of the path so as to not block the incoming particles. (Engineering )

I believe I read years ago in Scientific American where a chamber could be built with some sort of gel where the momentum could be calibrated by the path length through the substance...but I can't be certain...memory has been clouded by too many years of Cosmic ray strafing..
..

 

[Quantum_Grid]

There are other sites that have the "do-it-yourself" guides for making cloud chambers like these:

http://www.bizarrelabs.com/cloud.htm
http://scidiv.bellevuecollege.edu/Physics/Cloudchmbr.htm

They recommend using a radiation source for better results and they suggest some of the following as sources:

...Some (not all) old luminous watch and clock hands will work, as will some luminous paints. Trial and error will determine which ones work. Surprisingly, some older glassware (true cobalt blue) and ceramics glazes are slightly radioactive. It is also rumored that a popular brand of mantles for gas camper's lanterns are slightly radioactive (a Thorium isotope). And a reader points out that some smoke detectors contain a small sample of radioactive americium...

 

[Quantum_Grid]

Hate to be the guy that bumps his own thread, but really? Nobody has tried this or has recommendations for a better one?

 

[QuantumPion]

My physics professor in college had one of these, it worked great.

 

[Creator]

Hate to be the guy that bumps his own thread, but really? Nobody has tried this or has recommendations for a better one?

I'm waitin' on you to do it, QG...please let me know how it turns out.

BTW, the Americium in the smoke detector is a good idea for an alpha particle source, but its so low energy that it probably won't get farther than about a centimeter track.

Apparently the watch dials are beta sources...

Creator

 

[negitron]

You can get various radiation sources from http://www.unitednuclear.com/, in addition to other materials, literature and supplies for constructing various types of particle detectors and such.

Incidentally, Americium as found in smoke detectors is also a weak gamma emitter; in gram quantities, it emits intense gamma rays.

 

[Quantum_Grid]

Awesome! Thanks for the help. I will definitely try this out and post some pics when I can get all the stuff together.

 

[Quantum_Grid]

Wow, there's a lot there. Can you recommend a good source for the cloud chamber experiments?