# Cyclotron Magnet

The_Brain
I'm trying to build a small cyclotron and am thus searching for a magnet. I've been looking for a neodythium disc magnet that I could have cut in half to act as the two 'D' magnets in the cyclotron. The size of the magnet needs be somewhere around 12" in diameter but I can't seem to find anyplace that sells them around this size. If anyone knows where I could find some magnets or is willing to sell some of their own that would be great.

1.Don't try to cut neodym alloy - you won't be able to do that at home (it is very and very hard alloy). Ferrite is a little better, but too brittle. So, just get 2 magnets instead.

2. If you can't find two large magnets (equipment surplus web places can be a good place to start a search - Ti ion vacuum pumps have quite big slabs of ferrite magnets), then buy many small magnets and make a big one.

Last edited by a moderator:
why dont you start with a high-voltage linear accelerator and see how that goes first? you just need a very strong tube, a pump, and a voltage difference from either transformer or van de graff generator.

Staff Emeritus
Gold Member
The dees will need to be electromagnets, not permanent magnets.

- Warren

That's true, they will. And you might want to consult relavant physics textbook for equations and etc.

The_Brain
Thanks for all of the responses. First off, I've already built a linear accelerater using my own voltage multiplier I made, a pump, etc. I also know all the equations for figuring out the frequency I need to alternate the current, what the velocity of the particle given a certain strength of a magnetic field is and the length of path taken, etc.

When I first started thinking about this, I too thought I needed elctromagnets but then my high school physics teacher told me I needed permanent magnets. Thus, I was hoping to find a strong neomydium magnet disc that I could have someone professionally cut into two parts so I could have my two dee magnets. I guess now I need to search out for electromagnets, so if anyone knows where some are, that would be great!

Originally posted by chroot
The dees will need to be electromagnets, not permanent magnets.

- Warren

That is for synchrotron. For cyclotron an orbit just gets bigger and bigger with velocity.

Originally posted by Alexander
That is for synchrotron, not cyclotron.

For cyclotron an orbit just gets bigger and bigger with velocity.

Staff Emeritus
Gold Member
Originally posted by Alexander
That is for synchrotron. For cyclotron an orbit just gets bigger and bigger with velocity.
Er, uh...

You'll still need a strong permanent magnet to curve the paths of the particles (ions, electrons, etc.) in a cyclotron.

However, the poster was asking about the DEES -- which are, of course, not permanent magnets. They are, in fact, not magnets at all. The dees are two halves of a hollow metal disc, to which an oscillating electric potential is applied.

- Warren

nbo10
If only I would have read this a few hours before. I just tossed a huge electromagnet.

JMD