Cyclotron - Vacuum Chamber Materials

[Auxirius]

TL;DR Summary

TL;DR - Any suggestions on what kind of materials should be used for the vacuum chamber of the cyclotron aside from specific Aluminium Alloys that aren't incredibly expensive.

Hi all!

So recently me and a group of friends have begun working towards the construction of a cyclotron - and I was wondering, if anybody here would have an idea what kind of materials would be able to be used for the vacuum chamber that aren't specific Aluminium Alloys such as 7075 or 6061.
Of course, I am not saying I can't get Aluminium 7075 or 6061, it's just that I am wondering if there may be a cheaper / more common alternative.

-Auxirius

 

[trurle]

You can get A5052 aluminum alloy plate for approximately 60% cost of A6061, and A5052 is actually stronger. The problem is what many complex shapes are available only in A6061, therefore you likely end up with mix of A5052 and A6061/A6063 in complex installation. By the way, i do not recommend A7075 for non-mobile apparatus. It is strong material, but expensive and prone to corrosion.

 

[berkeman]

Welcome to the PF.

What are the preliminary dimensions of your cyclotron? What experience does your group have so far with high vacuum systems?

 

[Auxirius]

Hi! Thanks for the welcome.

We were planning to have an approximate diameter of 100-120mm with the circular plate around it approximately 50-70mm in height. (Apologies if this is hard to visualise, description is not my sort of thing) (Also, this is simply the vacuum chamber where the Dees will be put in and so on, the actual RF system and any other outside components are not included in these dimensions) .

Two of my group members claim they have worked with vacuums and vacuum pumps beforehand. They have never given me exact examples but I do know that I may trust them on this since they've always been the ones to work around with this sort of stuff.

About the dimensions once more - we are planning to create a relatively small cyclotron, though we are considering upping the size a bit if any problems arise with the current preliminary dimensions.

Once again, apologies if my description isn't great.
-Auxirius

 

[berkeman]

Thanks, that is helpful. Please be aware that we usually shut down threads like this because the amateurs attempting the build have no idea at all of the dangers involved, and likely will at best just get themselves hurt a little bit with the first accident in the project and give up.

So, can you please post what the main danger/safety challenges/issues are that are involved in such a project, and how you are addressing them? There are at least four main safety issues that are involved in such a project.

If you and your team seem to have a good handle on these issues, and if you have a very experienced faculty advisor who is leading this project, we may be able to let the thread keep going here. Otherwise, this thread obviously will be shut down for safety reasons, and we will advise you to keep pursuing this great project in your local university lab, where you do have the necessary supervision.

 

[Auxirius]

Hi! Sorry for my strange response times (timezones are a pain, and was asleep for a while)

We have been reading and researching the dangers of cyclotrons for quite a while in our preliminary design stage, and so, we are taking some main dangers into account:

1) To prevent any harm being done to us or anyone else - the cyclotron will be kept in a safe-spot away from anybody - lock and key sort of stuff - this will also be a safety precaution against violent implosions from the vacuum

2) To account for Radiation (both cyclotron and ionizing radiation), we will be using radiation shielding, though we are still considering what to use, but we will most likely use lead or some kind of other radiation-shielding material.

3) My friend who is in charge of creating a power supply to produce the power required took a few approaches before we settled on a Wimshurst machine - and his explanation of it: "So we'll have a Wimshurt machine charging up a capacitor bank through a spark gap, the capacitor bank will then be hooked up to an inverter, running off a 20MHz square wave." (I'm not the great one in the team about electricity, so if you have any questions or concerns regarding the electric side, I might take a while to respond). Regardless, the safety precautions taken for the supply of energy will practically be - keep it as far away from people as possible and the capacitor bank will be connected to a resistor when not in use so residual charges cannot build up.

4) Kind of a return to Point 2, this time focusing more on ionizing radiation since the Cyclotron we are building - we're hoping it should be able to produce MeV. Once more, we will have a lot of safety features to take into account about this, with radiation shielding mentioned beforehand that is going to be used.

5) Vacuum pump - fire hazard. Of course, we will have fire-safety measures around the testing area, though we are not sure if we will be using an oil-based one, though it is high likely.

Now, some overall safety features - Cyclotron will be kept in a sealed room at all times, whether being on or not - it will be used underground - We will have a button that will disconnect the capacitor bank from the inverter and connect it to a resistor which should stop the Cyclotron from operating and discharge the capacitor bank in a controlled manner if anything goes wrong. So overall: Cyclotron will be kept in a room underground, we will have an emergency shutdown switch -multiple radiation shielding materials - dangerous machines such as the power supply will be kept away from people, and people cannot enter the Cyclotron's room unless it is turned off - fire-hazard safety measures, etc.

That is all from me right now, if you have any additional questions, I look forward to them. If these safety features / measures do not satisfy your expectations, I apologise.

-Auxirius

 

[anorlunda]

Have a look at this:
https://www.physicsforums.com/threads/how-do-ion-sources-in-cyclotrons-work.970249/post-6172485

It is a group of amateurs who build a cyclotron under supervision of a professor. Maybe you could contact them.

 

[Auxirius]

Hi!

Thanks for sharing that link - I'll be sure to look into it.

 

[Vanadium 50]

If you try and build a cyclotron, the odds are substantially higher that you will injure yourself or a loved one than that your cyclotron will work.

Whenever someone says "I want to build a cyclotron", it is a red flag that they are too inexperienced to do so. Apart from risks like high voltage, vacuum, high current, x-rays and (if it manages to work) radiation and licensing, cyclotrons are not the simplest accelerator to make. People with enough knowledge to make them work know that this is not a good starting point.

 

[Auxirius]

Hi

I thank you for the warnings - and no worries, I am not the type to just go 'thanks for the warnings but I'll be fine'. I understand the dangers of the Cyclotron and perhaps there are some I have not known up until recently - which is why I am not going to build it anytime soon.

Me and my group are interested in the construction of one but we have a long way to go - and my question concerning the Vacuum Chamber was just out of curiosity if it ever came to be that we'd be building one.

In the meantime, we will either be working on other items or experimental equipment that might help us further our understanding of Particle Accelerators. So far - two of my friends are thinking of constructing a Wimshurst Machine (this is mostly just for electricity purposes apparently) whilst some others are saying we should try out a Cathode Ray Tube. In summary - the Cyclotron will most likely be our end project for when we have enough knowledge about it.

My question about the Vacuum chamber materials was sort of out of curiosity as my group wanted to make advances towards the construction of a cyclotron, so I assumed they wanted to begin the construction and so I was asking about the materials. If you'd have any recommendations / suggestions for something else to make that can help us out with Particle Physics / Particle Accelerators, I'd be happy to hear them.

-Auxirius