Request for Verified Specifications of Amateur Accelerators

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Michael Bretti
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Request for Verified Specifications of Amateur Accelerators

Post by Michael Bretti » Wed Jan 02, 2019 5:53 am

For those of you who have been following my progress, builds, and posts (both on these forums and in other hobbyist communities), you will know that I am currently in the process of designing and building an industrial-grade/research-class accelerator, which I hope will open up a new level of accelerator technology and research that has not yet, as far as I am aware, been explored before at the amateur level.

The accelerator build will be a fully open source home-built device, and completely designed and built from scratch from the ground up at the budget level of a decently-equipped fusor system (including exceptional scavenging and salvaging skills). I am currently in the design phase of the power supply for the accelerator, as well as a literature review of related systems that have inspired and preceded it historically.

In addition to my intensive research into similar past historic accelerators, I am also interested in looking at what has been prior accomplished at the amateur level. I would like to politely request the help of the knowledgeable members of this forum in this regard, in the event that I have missed anything in my search.

I was wondering if other members and enthusiasts here would happen to know and be able to provide specifications for the highest verified beam power, energy, and/or current for any type of amateur particle accelerator that has been built, either presented here on the forums, or elsewhere historically. This extends to everything from DC electrostatic accelerators, beam on target sources, ion sources, cyclotrons, etc. This includes both electron and ion accelerators as well. For amateur efforts, I am mainly looking for specs related to systems that have been built on one's own, separate of a research institute or company, and constitutes the definition of a truly independent, amateur built device. However, amateur efforts that extend to devices that have been built at universities using university resources are also welcome for comparison (though do not really qualify as a truly independent home-built amateur device). These specs do not all need to be concurrent for a single build. For example, one build could have the highest energy, another could have highest current, etc. I have searched extensively through what has been documented that I have found on the web so far, but I want to make sure that I have not missed any important information or efforts in this regard. This is not for design purposes, as the accelerator topology and major design parameters have already been established, but rather for a comparative review of prior amateur accelerator attempts and documentation purposes.

If all goes well and proceeds on time, I should expect first beam within the next few months, in which I will start releasing details and specifications of the build. Should I be completely unsuccessful (some risk, but very unlikely that I will not achieve any beam), all of the build information, design work, and documentation will still be available for others to build off of and further improve.

Thank you very much in advance for any information you are able to provide.

ian_krase
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Re: Request for Verified Specifications of Amateur Accelerators

Post by ian_krase » Thu Jan 03, 2019 8:37 pm

What type of accelerator is this - static, or some RF accelerator?

Chris Mullins
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Re: Request for Verified Specifications of Amateur Accelerators

Post by Chris Mullins » Fri Jan 04, 2019 1:39 am

I'm sure this is far from the highest by any metric, but with my cyclotron I've got protons up to 70 keV at around 2 pA, and as high as 4 nA in the 5-10 keV range (woo hoo!) I've seen H2+ beam currents in the hundreds of nA, but I haven't paid as close attention to that. Beam energy is computed based on resonance and pickup distance from center, not directly measured, so there is some uncertainty in that mighty 70 keV value. The resonance peaks are very distinct, repeatable, and exactly as predicted from the RF frequency and magnetic field, so it's pretty clear it's working.

The max theoretical energy in my design is around 300 keV; I'm probably a year away from achieving that (limited now by low Dee voltage, poor ion source, and vacuum conductance). I suspect beam current will still be in the very low nA range at best, double-digit picoamps is more likely.

Both these are college-supported:

Tim Koeth's cyclotron (http://koethcyclotron.org/) I believe can achieve 1 MeV for protons.

The student-built cyclotron at Houghton College is in the nA range of beam current typically, with a max achieved of 100 nA for H2+, and max proton energy of 157 keV (but at low beam current). I think 300-400 keV is the theoretical max for their system. More details in this PDF: http://www.houghton.edu/am-site/media/p ... fuller.pdf

Michael Bretti
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Re: Request for Verified Specifications of Amateur Accelerators

Post by Michael Bretti » Fri Jan 04, 2019 8:00 pm

Ian Krase,

Once I have achieved (or at least attempted) first beam, I will begin releasing information and specs on the accelerator. It is nothing new or novel - it is in fact a very old accelerator technology, that, as far as I am aware, has not been built at the amateur level yet (though I could be wrong, I am still searching extensively for any evidence of this type of accelerator being built and operated at the amateur level.) The accelerator will operate in two modes - high power mode, and high energy mode. The primary accelerator has been officially named EXEDA, which will be the main high power operating mode. A modified topology, named EXEDA-MEVI, will operate to produce higher output energies.

The type of accelerator that EXEDA is based on is a widely used, though much less discussed type of accelerator. The accelerator for EXEDA-MEVI however, based on my research, appears to be an incredibly niche and rare type of accelerator that appears to be largely forgotten and dead within the accelerator world now. Even talking to others in the field with decades of experience have not heard about it. However, I believe it has incredible potential for the hobbyist community. Both systems, if they work, would open up a lot of exciting physics experiments at the amateur level that have yet to be tapped or explored before at this level.

Sorry that this does not directly answer your question of the type of accelerator it is. It will be fully open source, but I would like to at least try attempt beam on this type first (if it hasn't already been done) before I release everything on it. Of course if it has already been done at this level then there will be little point of holding out info for after my first beam attempt.
Last edited by Michael Bretti on Fri Jan 04, 2019 8:22 pm, edited 1 time in total.

Michael Bretti
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Re: Request for Verified Specifications of Amateur Accelerators

Post by Michael Bretti » Fri Jan 04, 2019 8:21 pm

Chris Mullins,

Thanks a bunch for the specs on your cyclotron! It is great to see that you have very repeatable methods for determining beam current and energy. I definitely look forward to seeing how your effort progresses, and if you can hit your peak beam energy!

I have looked over Tim Koeth's work in the past, as well as the other largely referenced amateur cyclotron builds in the past. I did recently reach out to him inquiring about info regarding the amateur cyclotron community and what has been achieved in it so far, though I am sure he is incredibly busy. The other resource is great to have, thanks for the link to that as well.

I am curious to see what others have done partly because there is such an immense variation and discrepancy in results. What makes things even more challenging to sort through is that there are many countless claims by individuals across the internet over the years who have written about wanting to attempt or are in the process of "building" accelerators (many MeV level systems in particular), but very few actual hard, verified results. Like the fusor, there are many who have started out on the path to build an accelerator who make claims at the beginning, and just disappear after with no results. I could very well not achieve any beam myself, though I hope my extensively rigorous engineering design approach will help me overcome pitfalls related to this pursuit, and yield some results (even if not optimal).

I was thinking that as part of my effort, I would like to organize a list of documented and verified accelerator builds in the hobbyist community, and to compare methods and achieved results. I believe my approach to my accelerator has some unique advantages compared with other methods attempted in the past, though it means little until I actually have proven beam. The math and historic literature shows that it should work out in theory, but there is a big difference between reading and doing. The doing part is always the toughest.

I would like to modify my initial inquiry at this point and extend it to anyone here on the forums who has successfully built a working accelerator, regardless of resulting energy and beam specs, if resulting measured beam specs could be provided. I will of course search through the forums myself and compile an independent list, but it's always possible I can miss something given the shear volume of info to sort through here and elsewhere.

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