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Author Topic: What are the power sources for particle accelerators?  (Read 1417 times)

Offline eternity

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Sorry if any of these have been asked before, but I have looked on the internet and cant find any satisfactory answers.

If one of the particle smashers were to lose its power, would it be possible to just turn it back on again? If not, how long would it take to get it up and running again to safe levels?

Are different parts of the system (for example the computers, cooling systems, lights etc.) all run from the same power source?

How do they prevent the system from draining the power grid locally/nationally?

What would happen if they got an influx of power? Do they have a sort of 'fuse box' to work as a circuit breaker or would it be helpful?

Im sorry there are so many questions but I thought it better than making multiple posts.
If anyone can answer any one of the questions I would be most grateful as I cant afford to go to Switzerland just now and ask in person. Thanks
« Last Edit: 23/03/2014 23:15:57 by chris »


 

Offline evan_au

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Re: particle smashers - power sources
« Reply #1 on: 21/03/2014 10:17:19 »
CERN is probably the largest civilian* particle accelerator, consuming up to 200MW during summer months. This is a significant fraction of the output of a nuclear reactor.

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If one of the particle smashers were to lose its power, would it be possible to just turn it back on again? If not, how long would it take to get it up and running again to safe levels?
The LHC proton beam has about the same energy as a jumbo jet on landing. They have a beam dump facility to safely dump this energy within half a circuit of the beam line. Failing to dump it safely could punch a hole in the beam line, or destroy a magnet.

It takes about 8 hours to accelerate protons up to the maximum energy of the LHC - a process which occurs through a number of stages of increasing energy.

If the power was out for long enough to lose cryogenic cooling, it takes around a month to cool all the magnets down to operating temperature.

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Are different parts of the system (for example the computers, cooling systems, lights etc.) all run from the same power source?
CERN is normally powered from one substation in France, but has a Swiss substation as a partial backup. France has a very large fraction of its electricity from nuclear reactors, and they operate best when generating the same power all year around.

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How do they prevent the system from draining the power grid locally/nationally?
In Europe, residential power consumption increases in the winter months. So CERN shuts down the LHC during these months, significantly reducing their power consumption. This electricity is then used by residential and business users.

They would also have an arrangement with their power supplier that if the power was urgently required elsewhere (eg due to unplanned shutdown of a power station), CERN will start reducing power consumption within a few seconds to a few minutes.

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What would happen if they got an influx of power? Do they have a sort of 'fuse box' to work as a circuit breaker or would it be helpful?
The electricity grid as a whole has many mechanisms intended to prevent a sudden influx of power - this applies at the generating stations, the transmission systems, switchgear and in the particle accelerators themselves. Together, they usually do a good job of preventing power surges from damaging equipment.

One challenge is lightning strikes, which can easily overload systems - 30,000 Amps for 20 microseconds represents a significant overload for many systems, which could well trip out the power. Transmission lines usually have an earth wire above the power-carrying conductors, which should divert most lightning strikes to earth.

Another power surge risk in superconducting magnets such as the LHC is that a slight temperature rise, in conjunction with the powerful magnetic fields could cause the superconducting wire to suddenly become a normal conductor with far higher resistance. This dissipates considerable power, rapidly increasing the temperature and causing a helium explosion. A poor electrical connection in the original LHC caused exactly this situation, resulting in a shutdown of over 6 months.

For some podcasts on the LHC: http://omegataupodcast.net/2010/03/30-the-large-hadron-collider/
http://omegataupodcast.net/2012/06/96-controlling-the-lhc-beam/

*Any nation still using particle accelerators for uranium enrichment would probably consider the power consumption a military secret.
 

Offline eternity

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Re: particle smashers - power sources
« Reply #2 on: 21/03/2014 13:01:46 »
Fantastic, thank you very much! I really appreciate what you've written.

Ill cut and paste this so that I can re-read it a few times.

Have a good day!

 

The Naked Scientists Forum

Re: particle smashers - power sources
« Reply #2 on: 21/03/2014 13:01:46 »

 

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