LHC First Run Parameters

By JoAnne Hewett | August 6, 2009 9:58 am

A question that we have all been asking has been answered today: What will be the LHC run energy?  A press release has just been issued from CERN Director General, Rolf Heuer, following the completion of tests on the LHC magnets and splices.  Here are the excepts which just beeped into my inbox:

The LHC will run for the first part of the 2009-2010 run at 3.5 TeV per beam, with the energy rising later in the run. That’s the conclusion that we’ve just arrived at in a meeting involving the experiments, the machine people and the CERN management. We’ve selected 3.5 TeV because it allows the LHC operators to gain experience of running the machine safely while opening up a new discovery region for the experiments.

The developments that have allowed us to get to this point are good progress in repairing the damage in sector 3-4 and the related consolidation work, and the conclusion of testing on the 10000 high-current electrical connections last week. With that milestone, every one of the connections has been tested and we now know exactly where we stand.

The procedure for the 2009 start-up will be to inject and capture beams in each direction, take collision data for a few shifts at the injection energy, and then commission the ramp to higher energy. The first high-energy data should be collected a few weeks after the first beam of 2009 is injected. The LHC will run at 3.5 TeV per beam until a significant data sample has been collected and the operations team has gained experience in running the machine. Thereafter, with the benefit of that experience, we’ll take the energy up towards 5 TeV per beam. At the end of 2010, we’ll run the LHC with lead-ions for the first time. After that, the LHC will shut down and we’ll get to work on moving the machine towards 7 TeV per beam.

This is welcome news.  Starting at injection energy (450 GeV/beam) for a few shifts is safe and smart.  Experimenters will be guaranteed to record some data which will be used to calibrate the detectors.  Detectors must be properly aligned and calibrated before we can have discoveries!  Then they will ramp up and run awhile at 3.5 TeV/beam, giving the LHC its long-awaited status of being the highest energy accelerator in the world.  A short run at this energy does not have much discovery room given the strong constraints on new physics from the Tevatron, but will mainly serve to further calibrate the detectors and build up experience running the machine.  Finally, a slow ramp up to 5 TeV/beam seems like a safe option for the machine, and allows for the possibility of discovery by the end of 2010!

  • graviton383

    This is good news & a smart move…I think this is the way to go. Maybe JoAnne can tell us how the physics reaches are reduced by going to lower energies..

  • JoAnne

    Ha! Graviton383 is a shill in our CV audience. I am planning to post on that soon….

  • Dylan

    But…but… I want science NOW!

  • http://www.myreference.com/ My Reference Frame
  • Sili

    As long as the thing doesn’t blow up again, I don’t mind if it takes them a decade to get through the available searchspace.

    I feel fairly confident that I’ll still be around for the next two or three accelerators.

  • federico

    JoAnne, thanks for the updates on the rebirth of the LHC!
    Do you know how much integrated luminosity may be reached at 7 TeV? (and will it be of any use before the detectors are calibrated?), and how much on the way to 10 TeV? Do you think the experimentalists will have their Monte Carlo simulations ready on time?

  • student

    I believe the goal would be to have 100’s of pb-1 of integrated luminosity by the end 2010 with 7 TeV. This should make the LHC competitive with the Tevatron in a number of areas (SUSY), but you can’t really say much about a standard model Higgs with that amount of data at that energy.

  • onymous

    I feel fairly confident that I’ll still be around for the next two or three accelerators.

    Planning to live until 2200?

  • Ellipsis

    We physicists can decide the energy at which we will _attempt_ to run the LHC, but the machine itself will obviously have final say on whether it is willing to function at that energy, or at all, this winter.

    As they say in the Arab world, “Inshallah”…

  • AnonyGradStudent

    > A question that we have all been asking has been answered today: What will be the LHC run energy?

    As a student at one of the detectors at LHC for the past 4 years, it feels like we’ve perpetually been a few months from first data. I’m skeptical this time will be any different. (I’m hopeful, because graduation depends on it!) The steady creep downwards in center-of-mass energy from 14 TeV to now 7 TeV has been scary too.

    Last fall (2008) the accelerator ran into a (big) problem after running for several days – but what about the problems we would only have discovered after running several weeks? Or several months?

    It is nerve-wracking and frustrating for me, because I’m helpless – it’s out of our hands and in the hands of the accelerator people.

    I hope they deliver collisions this time, and I hope it will be an exciting time this fall and next year in our detector’s control room.

  • Jimbo

    Possible new discoveries await if the CM energy is set to 2.4 Tev = sqrt{Mcc*Mpl}.
    Worth a shot, after waiting another boring year at the mercy of Murphy’s law.

  • Christina Viering

    Sounds like a good ride.

  • Shantanu

    Slightly off-topic question. Are the videos of the lectures from 2009 Slac summer institute going
    to be uploaded? I only see ppt files. It could be great if they could.

  • Count Iblis

    Meanwhile, amazing discoveries have been made in the parallel world where the SSC was not shut down :(

  • bigjohn756

    Ohh, I am almost 71. I really want to see some good stuff from the LHC before I leave. I really wanted to see some good stuff long ago from Waxahachie, but, of course, oh, well never mind…

  • Techno

    Relax folks. Even without the power blowout it is still wise to ramp up to 7TeV in stages. We are talking a most complicated and powerful machine, one of a kind. Absolutely need operational experience, steady hands and steady nerves. The best of the best are in charge. Let them do their thing, and that including fixing a few problems that will surely crop up before 7TeV is reached. Let’s give the LHC engineers a big hand and support them.

  • Buzz

    A very cool Site.



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