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1. Dec 10, 2011

### diy

Hello!

Long time reader, first time poster. First, I am sorry for my bad English, but I havent practiced from a very long time and this is not my native language.

So, I am studing Physics. I and a classmate make DIY projects. Weve made quite a big list of things - R/C models, tesla coils, Brown gas generator, CNC machine, etc... Of course we are not only interested in building something, but investigating the principles and the way it works.

Recently we are thinkig of making a small (tabletop) particle accelerator. We have people who can help and a small (garage) workshop. Problem is, that I dont know were to start. Ive searched trought internet and mostly links arent working and information is small.

I am looking on any ideas on that. I know CRT TVs and monitors are a kind of a accelerator. Please, dont tell me that "it isnt possible"

http://www.instructables.com/id/DIY-Electron-Accelerator-A-Cathode-Ray-Tube-in-a-/

Sorry, for wrong sub-forym thread should be in General Physics.

Last edited: Dec 10, 2011
2. Dec 10, 2011

### torquil

Depending on the voltage and shielding, such machines may produce Röntgen-radiation which is known to cause cancer in too large doses.

3. Dec 10, 2011

### diy

Cant I use a electron gun from a CRT monitor to accelerate some electrons in a cloud chamber?

4. Dec 10, 2011

Staff Emeritus
You don't need that, and it would be dangerous. Cosmic rays are just fine to see tracks - you'll get one every few seconds.

5. Dec 11, 2011

### sophiecentaur

The sort of cloud chamber that you normally come across uses Radioactive sources to produce the tracks. By definition, a cloud chamber is not evacuated so how would you get your crt electron gun (evacuated) to fire electrons into it, at atmospheric pressure?

6. Dec 11, 2011

### diy

Okey, a new Idea - I will use a Cockcroft Walton generator to get a electron flow in a vacuumed pipe.

7. Dec 11, 2011

Staff Emeritus

A very likely outcome is your injury or death. Stick with the cloud chamber.

8. Dec 11, 2011

### diy

9. Dec 11, 2011

### sophiecentaur

There seems some confusion. A Cloud Chamber is, surely, a detecting device and not an accelerator.
Accelerating voltages of a few tens of kV will produce harmful X rays. Why would you want to do that? For a safe experiment at those energies you need a High Energy Physics Lab, with all the safety measures (loads of Lead, for a start). Where are you planning to get the source to use with your cloud chamber? You might lay your hands on some naturally occurring radioactive rocks??
I think this is out of your league. Steer clear.

10. Dec 11, 2011

Staff Emeritus
You can get nice cosmic ray tracks in a cloud chamber. But an accelerator is dangerous, and frankly, unlikely to work.

11. Dec 12, 2011

### diy

As I sad I am not interested in a cloud chamber, its just a simple detector. I am interested in an accelerated ion/electron flow.

12. Dec 12, 2011

Staff Emeritus
And we are telling you it's dangerous. And unlikely to work.

13. Dec 12, 2011

### sophiecentaur

You will not be aware, at the time, of any harm that Xrays will do to you - just later on when you develop some form of cancer.

When I was a lad we used to make fireworks instead - and remove fingers or blind ourselves. Also not to be recommended.

14. Dec 12, 2011

### Drakkith

Staff Emeritus
Beside the safety issues, are you prepared to spend several hundred dollars minimum to get the required equipment? (Or more likely a few thousand) The Vacuum pump and assorted equipment aren't cheap nor are the easy to work with. The kind of vacuum you need would require a forepump for rough vacuum, and a second, much more expensive pump to get the vacuum down from the rest of the way.

15. Dec 12, 2011

### Bobbywhy

So you are thinkig of making a small (tabletop) particle accelerator. If you consider particles to be ball-bearings, for example, you might make a linear particle accelerator using alternating electric (magnetic) fields to add kinetic energy to the object. The same general principles used in sub-atomic particle accelerators should be applicable.

16. Dec 12, 2011

### e.bar.goum

And as a bonus, is unlikely to give you cancer. Wounds from high speed ball-bearings, perhaps, but not cancer.

17. Dec 13, 2011

### sophiecentaur

Actually, if you make or buy a Van der Graaff generator (cheap), you can see streams of ionised particles if you hold a large light bulb near it.
Also, you can produce a pretty impressive plasma when a light bulb is placed in a microwave oven. I am not recommending that you actually do this at home as I don't want to be held responsible for what happens when the bulb shatters or you Mum comes in. The oven should only be on for a very few seconds. There is also a plasma experiment using a grape in a microwave. Do not do this do not do this. haha but look on You tube.

18. Dec 13, 2011

### diy

Yes, I can walk down the street and a brick may fall on my head and kill me, but that doesnt stop me walking down the street.
Ive made the microwave experiments already and they are not a big deal. I cant understand you... if you tell me that I can make plasma in my microwave, I try it and than something happens... you will be responsible? If thats so you will never tell me anything about particle accelerators...

19. Dec 13, 2011

### dmriser

diy,

I also like to make things in my garage. You can build many things that will teach you about physics after you see them work. In my opinion, a particle accelerator does not fall in this catagory and you need to first learn everything before starting the project. I too wanted to build an accelerator, I spent time researching these devices (I have also taken many of the relevant courses in university). After all of this my conclusion was that it's safer, simpler, and more affordable to skip the particle acceleration as a project.

For whatever reason (could be language barrier) your recent posts have sounded somewhat abrasive. If you still want to make a device that accelerates particles I suggest that you start reading as much as possible online. There are a few guides written by amateurs on a home built accelerator. These guides talk extensively about safety and would be a good read if you are really set on doing this (I do not have links). To close, if you really want to do this please do your homework and know the dangers. I do not want to speak for the community but my feeling is that you won't get help building this device here.

20. Dec 13, 2011

### Drakkith

Staff Emeritus
First of all, PF has a rule against helping people make illegal or dangerous items. While this is usually related to explosives, drugs, etc, I could see this falling under it. Not only does this have the capability of harming you, but it can also harm anyone in the immediate area.

Second, what you are asking is simply too broad of a subject. This isn't a site dedicated to making something like this. I'd be willing to bet most of the people here don't even know where to start. Like I said, if you have specific questions such as how to find the shielding required for a certain amount of radiation using a certain material, that might be answerable.

So considering the items above it is no suprise all you are getting is "It's dangerous, don't do it."
It isn't that no one wants to help you, it's that most people cannot and the few that MIGHT be able to think it's simply too dangerous for someone who isn't trained.