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LHC beam energies

  1. Mar 23, 2010 #1
    What is the highest possible energy per beam that the LHC can handle?
  2. jcsd
  3. Mar 23, 2010 #2
    7TeV per beam 14TeV total I believe. So it will be half max on 30th...if all goes well(touch wood).
  4. Mar 23, 2010 #3
    It was initially planned for 7 TeV per beam ... but now it turns out that no one really knows how much magnets can handle. Fingers crossed, we might get to 5 per beam if we're lucky.
  5. Mar 24, 2010 #4
    Last edited by a moderator: Apr 24, 2017
  6. Mar 24, 2010 #5


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    I guess that you think of energy per proton and not per beam.
  7. Mar 24, 2010 #6
    Yes, the numbers quoted are per proton. It was designed to run at 7 TeV per proton (or a center-of-mass collision energy of 14 TeV). In light of the problems they had with the magnets, they decided that to avoid risk they will run for ~2 years at 3.5 TeV beam energy, and then shut down to replace all the interconnects before resuming and ramping up to full design energy.

    So it's a good bet that they'll eventually have 14 TeV collsions, it will just take a while.

    As for the total energy in the the beam at one time, I'll let someone else answer that since I don't know offhand, but it's considerable. I believe they'll eventually have a pretty high luminosity.
  8. Mar 24, 2010 #7

    Vanadium 50

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    The total energy in the LHC a week from now will be on the order of 200-300 kJ - about the same as the food energy in a potato. This is calculated assuming 4x4 bunches, 3.5 TeV per proton, and 5-6 x 1010 protons per bunch.
  9. Mar 24, 2010 #8


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    At full energy and full power the LHC contains about 350MJ /beam

    They helpfully convert that into units of aircraft carriers steaming at X knots - for both British and American aircraft carriers.
    (In case you were wondering it's equal to HMS Illustrious at 12Knots or USS Nimitz at 5.5knots)

    Actually turning the thing off and getting rid of this energy without making a mess is a big part of the design
    Last edited: Mar 24, 2010
  10. Mar 24, 2010 #9
    That is a lot of energy, and the LHC detectors might produce 10^34 collisions per second and per cm^2. A layman would assume that there is a lot of heat produced going one, but these collisions happen in a vacuum, where heat transfer is only possible by conduction and/or radiation. Where does the energy actually goes? And if there is a cooling installation doesn't this affect the results?
  11. Mar 24, 2010 #10
    The LHC beam dumper is located in point 6 of the main ring. Basically it will take a magnet and deflect each beam into a very large concrete and iron lined, water cooled carbon chamber which absorbs the beam.
  12. Mar 25, 2010 #11
    That's cool, and what happens to the temperature in rooms where the collisions are do these detectors get red hot?
  13. Mar 25, 2010 #12
    Note that the 350 MJ refers to dumping the entire beam. The collisions that are being studied only happen a few at a time, so the resulting ~10^-6 J of total energy added to the detectors as a whole from each event is negligible (as far as I know anyway).
  14. Mar 27, 2010 #13

    Vanadium 50

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    The power in collisions entering the detector at design is measured in watts. In the early phase, mW or even uW would be more appropriate. "Red hot" is not in the realm of possibility. By far the more important source of heat is all the electronics.
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