How to Build A Cyclotron

[higgsnerd137]

Does anybody have any tips/ advice on building a simple cyclotron? I read about Michio Kaku making an accelorater when he was a teen and was wondering how to make one.

 

[ephedyn]

I had a similar idea in mind (but different motivations), and I'll like to point out that there's no "simple" cyclotron. I started my project about 1 year ago expecting to finish it last month, and now I've come to the impression that it will end somewhere around the end of this year (including construction, troubleshooting and finally some experimentation); and some other people will take up the continuation of my project after that. I spent about 1100 hours on the project, just studying engineering concepts (more so than physical concepts) before I started work on building anything.

It will be faster if you have experience with electronics/electricals.

My advice is to first read the original paper by Lawrence and Livingston, then go take a look at Fred Niell's site (www.niell.org), and Rutgers University's site. Then you'll have an idea of the different components. That's where you can split up what you have to read up, because putting together and operating the various components will require background knowledge that is nearly independent of each other.

Will like to write more but I'm really ill at the moment, and there's really too much to write. If you need more specific help, feel free to ask me.

 

[Bob S]

Rutgers cyclotron project:
http://www.physics.rutgers.edu/cyclotron/papers/12_inch_magnet_studies_4.pdf
This paper has a good section on vertical and radial focusing.

Bob S

[added] Here are some recent results from the Rutgers cyclotron, including pics of the accelerated beam and of the open vacuum chamber.
http://www.physics.rutgers.edu/cyclotron/

 

[higgsnerd137]

How did you get the vacuum?

 

[ephedyn]

You need

1) an oil diffusion pump and a rotary vane pump, or
2) a turbomolecular pump and a rotary vane pump

The cyclotron is typically installed in a cylindrical vacuum chamber with dimensions slightly larger than the electrodes. Because of the various requirements, ports and fittings etc., you probably won't find a ready-built chamber. You'll have to design and machine one on your own. Aluminium and 304 stainless steel are useful for making the chamber.

Again, that's just on the surface of things. There's a lot more work to get it down.

 

[bjacoby]

Does anybody have any tips/ advice on building a simple cyclotron? I read about Michio Kaku making an accelorater when he was a teen and was wondering how to make one.

My tip is "don't try it!". Cyclotrons are very complex and expensive devices requiring expensive large magnets, expensive quality vacuum systems, relatively high powered RF transmitting gear, plenty of complex machining and construction as well as highly advanced calculations needed to get the beams focused etc. It is not a hobby project even in a small scale.

Now when I was a teen I build a one million volt Van de Graff generator that was to be the heart of an accelerator capable of a low energy nuclear reactions. It took some time but was a doable project. I never did finish the accelerator tube part of it, but I did have all the vacuum system and other things to do it. Was a nifty (if large) device! Plans were in some old issue of Scientific American back around the 60s I think.

Other alternatives would be a Betatron which also involves a large magent (but laminated this time) and is much simpler to build, but is not capable of nuclear reactions so it's not as cool in that regard.

Voltage multiplier type accelerators of a linear type are pretty easy to build too. I'm thinking that probably one might equal the performance of the Van de Graff I built without too much trouble with modern components.

Of course it's pretty easy and plans abound to get pretty high voltage from Tesla coils. The accelerator problem is that the high voltage is high frequency RF which would either have to be converted to DC or somehow deal with the time of flight problems in a linear tube. Tesla, however claimed to have actually smashed atoms with his coils but how he did it was never revealed. He did obtain amazing X rays for the period.

Good luck!

 

[ephedyn]

Yeah, it is a serious project, but I wouldn't dissuade one from trying it. There's a lot of interesting things to learn even if it's unsuccessful... and it's not like you'd be able to splurge on expensive equipment until you are fairly knowledgeable/skilled. I spent a couple of weeks of holidays just purely (>12h/day) flipping through catalogs and technical drawings to figure out how standard fittings work - it's not as easy as shopping for a shirt!

And the dangers are progressive - you need to know how to set up a filament before you can get protons, before the low voltage (>1kV) amplifier comes into the picture; acquire a vacuum through some pretty deep mechanical engineering, before you can acquire high speed ions, before the radiation shielding comes into play.