Usefulness of a low energy cyclotron

[Snow510]

I'm exploring building a very small basement cyclotron. I have a solid professional electrical engineering background; the only major new technology for me would be the ultra-high vacuum, so I think it's at least possible. I've been going through Humphries' Principles of Charged Particle Acceleration and other online sources to get background information.

To keep things manageable, I was thinking of a very low energy proton cyclotron, e.g. in the 10-100 keV range, and very low beam intensity (microamps). The low output requirements would allow for sloppy/inefficient beam extraction from the Dees, small magnets, poor beam focusing, and likely many other bad design elements I wouldn't even be aware of, and yet still get some protons out of it roughly going in the same direction.

Are there any interesting amateur uses for a basement cyclotron in that range? Any nuclear reactions possible? I'm not asking how to build such a cyclotron, but rather, if I did, what's possible at that level? I'd like to set the design goals for the minimum output energy and intensity possible where it could still produce interesting results with some targets.

 

[berkeman]

I'm exploring building a very small basement cyclotron. I have a solid professional electrical engineering background; the only major new technology for me would be the ultra-high vacuum, so I think it's at least possible. I've been going through Humphries' Principles of Charged Particle Acceleration and other online sources to get background information.

To keep things manageable, I was thinking of a very low energy proton cyclotron, e.g. in the 10-100 keV range, and very low beam intensity (microamps). The low output requirements would allow for sloppy/inefficient beam extraction from the Dees, small magnets, poor beam focusing, and likely many other bad design elements I wouldn't even be aware of, and yet still get some protons out of it roughly going in the same direction.

Are there any interesting amateur uses for a basement cyclotron in that range? Any nuclear reactions possible? I'm not asking how to build such a cyclotron, but rather, if I did, what's possible at that level? I'd like to set the design goals for the minimum output energy and intensity possible where it could still produce interesting results with some targets.

Welcome to the PF.

What kinds of safety issues do you see that you will need to deal with in this proposed project? Have you worked with X-rays and unintentional EM radiation in the past? What experience do you have with vacuum vessel construction and safety?

 

[Snow510]

Welcome to the PF.

What kinds of safety issues do you see that you will need to deal with in this proposed project? Have you worked with X-rays and unintentional EM radiation in the past? What experience do you have with vacuum vessel construction and safety?

The most obvious safety issue is the HV drive to the Dees. I wouldn't expect much X-ray output with proton acceleration, but I'd be happy to read any references about that. From what I've read, most of the radiation hazard would be from protons directly and neutrons from proton collisions. If I actually got that far, shielding would probably be either large blocks/sheets of paraffin, or borax water in stackable HDPE containers.

I don't have any X-ray experience, but do have quite a bit of professional experience with unintentional EM radiation from an RF standpoint (e.g. FCC/CE emissions testing, not safety), and also UL testing with high voltage systems.

I don't have any vacuum experience to speak of. After spending a few weeks reading the fusor.net forums, the Bell Jar archives, etc. I've just started to experiment with home made vacuum chambers, but it would take quite some time (and investment) before I could achieve UHV levels, especially since I'd be TIG welding parts of this myself.

Anyway, before I proceeded further with an up-front analysis of what's required in terms of cost, skills needed, likelihood of success, etc. I wanted to investigate if it's worthwhile even in the best case. If, after all that time and effort, a very small cyclotron isn't that useful or interesting for any amateur recreation, there's no point in going further even with a paper design. Or, another way of asking the question is, what's the smallest cyclotron output that would be interesting? 5 keV? 50 keV? 0.1 uA intensity? An absolute minimum output spec would let me do some order of magnitude estimates on the rest of the project, and help determine if it's feasible or not in basement environment. I'd define that roughly as under 6 kW of total input power (magnets + RF), and within a 14x14 foot space (including any shielding).

Any thoughts?