Particle accelerator

Thread Starter

Robin Mitchell

Joined Oct 25, 2009
819
Hi everyone,

I plan on making a linear particle accelerator. it would consist of an electron gun to get electrons and a long chamber to accelerate and focus the beam. The only thing is how would you accelerate the electrons once they have left the gun?
Thanks
 

jpanhalt

Joined Jan 18, 2008
11,087
Do you really need an electron gun? What about a pointed needle or hot filament? Or, harvest the source from a TV tube or other CRT. If you have access to a library that has past issues of Scientific American, I mean really past issues, check Amateur Scientist, circa 1954 -1957. There were complete plans for a high-vacuum pump and linear accelerator. I made one. They were quite popular for science fair projects then. I used mine to irradiate some plastics (beta) and see whether it affected their melting point.

Oh, BTW, being able to do a little glass blowing will help, but is not necessary. You can use various waxes for sealing. The SA article suggests a mixture of beeswax and rosin.

John
 

Thread Starter

Robin Mitchell

Joined Oct 25, 2009
819
If i have two sets of two plates to accelerate electroncs through like this:

---- ----

---- ----

Each having a PD of 1V, when the electron travels all the way through does it have 2eV of energy?
Thanks
 

jpanhalt

Joined Jan 18, 2008
11,087
You lost me there. What direction are the electrons traveling? One volt potential difference is 1 eV, right?

If your acceleration potential is 50,000 to 500,000 volts, why worry about a few volts for your source. Get the hard part (accelerator, vacuum system, no leaks) built first, then you can mess with the source. A source without the rest of the system is worthless. BTW, getting rid of leaks is a real challenge. What are you using for your vacuum system? How will you find leaks? How will you measure the pressure?

John
 

Thread Starter

Robin Mitchell

Joined Oct 25, 2009
819
No idea, im getting a group of friends to do this with me. We will deal with that, what i want to know is if an electron accelerates through a PD of 1v and then through a pd of 2v, does it get 3ev of energy?
 

jpanhalt

Joined Jan 18, 2008
11,087
You showed a drawing, but omitted the electron.

Maybe this will help. Seems pretty clear to me.

http://en.wikipedia.org/wiki/Electron_volt

In physics, the electron volt (symbol eV; also written electronvolt[1][2]) is a unit of energy equal to approximately 1.602×10−19 J. By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an electric potential difference of one volt.
John
 

Thread Starter

Robin Mitchell

Joined Oct 25, 2009
819
mmmm

Here is the story

One day an electron accelerates through a pd of 1v. This means he has gained 1ev.

Now, while traveling through the accelerator, he goes through another pair of plates which have a pd of 1v....does this mean he now has 2ev?

----
e-->
----
1V

E now has 1v
---- -----
e-------------------->
---- -----
1V 1v

when he leaves the next plate, does he have 2ev?
Please try and understand
 

retched

Joined Dec 5, 2009
5,207
For leak checking, smoke is good.

In the HVAC field, we used smoke to check for leaks regularity.

HVAC Schrader valves are your friend. You can get them cheap and they are designed to hold a vacuum down to 25 micron.

Find a friend who works in the HVAC field to join your project group.

They will have access to vac pumps and fittings that can produce and hold the vacuum.

Dont skimp on your valves. The HAVE TO hold the vacuum.
 

retched

Joined Dec 5, 2009
5,207
You need somewhere to start. ;)

The more people you get on-board, the less each has to spend.

Yeah, you are going to need some serious vacuum pumps.
 

Thread Starter

Robin Mitchell

Joined Oct 25, 2009
819
Cool
Im doing A2 physics at the moment and we are looking a quarks, some great stuff!
I originly wanted to make a proton/alpha particle accelerator but i dont know how to get a stream of protons :/
 

Thread Starter

Robin Mitchell

Joined Oct 25, 2009
819

jpanhalt

Joined Jan 18, 2008
11,087
Cool
Im doing A2 physics at the moment and we are looking a quarks, some great stuff!
I originly wanted to make a proton/alpha particle accelerator but i dont know how to get a stream of protons :/
Once you get your electron source working in your particle accelerator, just introduce a little hydrogen into the source and reconfigure as a mass spectrometer. Simple.

John
 

BillO

Joined Nov 24, 2008
999
mmmm

Here is the story

One day an electron accelerates through a pd of 1v. This means he has gained 1ev.

Now, while traveling through the accelerator, he goes through another pair of plates which have a pd of 1v....does this mean he now has 2ev?

----
e-->
----
1V

E now has 1v
---- -----
e-------------------->
---- -----
1V 1v

when he leaves the next plate, does he have 2ev?
Please try and understand
Well, if the pairs of plates have 1v WRT each other, then yes, but if there is 1V PD between the plates and ground then no. Or if the PD is across the plate pair then that will just delfect the beam.

See the attached. Each stage is a circular plate with a hole in its centre, like a washer. There is 100KV PD between each plate.

 

Attachments

Thread Starter

Robin Mitchell

Joined Oct 25, 2009
819
i think i get it billO
So the electrons accelerate through the hole towards the ground plate at the end?
what if i had one 100kv source, can it still be done like that?

What can high energy electron collisions be used to do then?
 
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