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Author Topic: Why do particle accelerators have to be so big?  (Read 6466 times)

Offline Geezer

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Why do particle accelerators have to be so big?
« on: 02/07/2011 23:09:27 »
What's going on with these things, eh? Sheesh, the one at CERN is so big they couldn't fit it all in Switzerland.


 

Offline Mr. Data

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Why do particle accelerators have to be so big?
« Reply #1 on: 03/07/2011 00:10:23 »
The larger they are, the more energy they pump into distances created for it. For instance, there is an energy level in physics, called the Planck Energy. No physical accelerator today can reach that energy, but if you made one the size of the solar system, you could potentially reach that energy level.
 

Offline MikeS

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Why do particle accelerators have to be so big?
« Reply #2 on: 03/07/2011 06:31:19 »
I imagine it's also to do with the bigger the diameter the closer the circumference is to a straight line.
 

Offline imatfaal

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Why do particle accelerators have to be so big?
« Reply #3 on: 03/07/2011 11:02:04 »
That's an important point Mike - as you move a charged particle in a circle you are accelerating it inwards; charged particles under acceleration radiate .  This radiation is called synchrotron radiation - this means that unless you want the particle to radiate its energy away you keep the radial acceleration as low as possible.  To do this you either use a linear accelerator or you make the circle very big, as you suggested.

Synchrotron radiation is a very good way of producing strong and regular radiation and what might be an annoying bye-product at some accelerators is the desired product at places like the Diamond Light Source

http://www.diamond.ac.uk/Home/About.html

 

Offline MikeS

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Why do particle accelerators have to be so big?
« Reply #4 on: 03/07/2011 11:18:13 »
Imatfaal

We agreed on something?   :)
 

Offline imatfaal

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Why do particle accelerators have to be so big?
« Reply #5 on: 03/07/2011 11:23:31 »
Imatfaal

We agreed on something?   :)
;D
 

Offline Bored chemist

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Why do particle accelerators have to be so big?
« Reply #6 on: 03/07/2011 13:26:22 »
"The larger they are, the more energy they pump into distances created for it. "
Pardon?
There are so many assumptions in the suggestion that "No physical accelerator today can reach that energy, but if you made one the size of the solar system, you could potentially reach that energy level." that it's impossible to say whether it's true or not.
Getting roughly half a megawatt hour of energy into one particle would still be tricky, no matter how big the accelerator was.
 

Offline Mr. Data

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Why do particle accelerators have to be so big?
« Reply #7 on: 03/07/2011 16:20:47 »
"The larger they are, the more energy they pump into distances created for it. "
Pardon?
There are so many assumptions in the suggestion that "No physical accelerator today can reach that energy, but if you made one the size of the solar system, you could potentially reach that energy level." that it's impossible to say whether it's true or not.
Getting roughly half a megawatt hour of energy into one particle would still be tricky, no matter how big the accelerator was.

Do you know of Michio Kaku, he was asked to create a time machine. He made one, but required wormholes - he did this by hypothetically creating an accelerator the size of the solar system to reach that energy.

He is a top-leading physicist - I'd rather trust him than you.
 

Offline Bored chemist

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Why do particle accelerators have to be so big?
« Reply #8 on: 03/07/2011 16:54:01 »
WTF?
"The larger they are, the more energy they pump into distances created for it. "
Do you realise that your sentence (quoted above) makes no sense?

I'm well enough aware of Mr Kaku's work to have heard his estimate that it would take the energy from a star to make a time machine.
I said it would be tricky.
Do you really disagree with that assessment?

 

Offline Mr. Data

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Why do particle accelerators have to be so big?
« Reply #9 on: 03/07/2011 17:54:01 »
WTF?
"The larger they are, the more energy they pump into distances created for it. "
Do you realise that your sentence (quoted above) makes no sense?

I'm well enough aware of Mr Kaku's work to have heard his estimate that it would take the energy from a star to make a time machine.
I said it would be tricky.
Do you really disagree with that assessment?



Yes my sentance was really quickly written last night as I was logging off. crux of the problem, is that distances can only be acheivable by pumping enough energy into your accelerator. Your final spray of particles will be full of energy, kinetic energy, due to their motions inside the accelerator.

My assessment with what you said, ''but if you made one the size of the solar system, you could potentially reach that energy level." that it's impossible to say whether it's true or not.'' - which maybe true. But we know roughly how large an accelerator should be to reach the planck energy, and it is according  to Michio, roughly the size of the star system.
 

Offline syhprum

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Why do particle accelerators have to be so big?
« Reply #10 on: 03/07/2011 19:51:17 »
If you want to accelerate charged particles to a high velocity there are basically two ways you can do it , either in a straight line or around a circular track.
The particles start of at a relatively low speed and pass thru accelerating stages powered by Klystron radio frequency generaters.
There is a well defined limit as to how close together these stages can be hence you very soon come to the limit with a straight design.
With a circular design the particles pass thru the same accelerating stages many times but must be subjected to the fields of bending magnets to keep them circulating the smaller the radius of the track the stronger the field of the magnets must be.
There is a practical limit to how Strong a field can be generated by the superconducting magnets used so when you are up to that limit as is CERN the only way forward is to increase the diameter of the track.   
 

Offline Bored chemist

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Why do particle accelerators have to be so big?
« Reply #11 on: 04/07/2011 06:55:14 »
Distance is not the issue.You can always go round the track more times if you need more stages of acceleration.
The real problems with small rings are ,as has been said, synchrotron radiation and the magnetic field strength you need.
If you calculate that you need a ring the size of the solar system I will point out that it will take a lot less power to run if you make it twice as big.
It's not an absolute limit set by physics, there are trade offs.
 

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Why do particle accelerators have to be so big?
« Reply #11 on: 04/07/2011 06:55:14 »

 

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