Latest From the LHC

Things have been going fairly well at the LHC, with no major problems encountered recently as the machine is being prepared for operation. The last two sectors (34 and 67) are almost cool (see more about this here). Not mentioned in the CERN Bulletin article is that there has been about a week and a half slippage with respect to the schedule of a month ago, with the current schedule having powering tests finishing in the last two sectors around November 20. Attempts to circulate beams and begin the beam commissioning process should begin shortly after that.

CERN has also recently decided how to handle the media campaign for this second attempt to start up the machine. Unlike last year, there will be no media event associated with the first circulation of beams, just press releases issued at that time, at the time of first collisions at 450 GeV, and at the time the beam energy is raised to a world record (above that of the Tevatron, 1 TeV). There will be a media event planned for first collisions at 3.5 TeV/beam, but the date for this will only be planned about 2 weeks before it happens, and confirmed a day or two before the event. It’s possible that this will happen later in December, just before the holiday shutdown, but maybe it’s more likely for January. CERN has a web-site set up for the media on this topic, see here, where all they say “The first high energy collisions will most likely occur at a date after mid-December 2009.”

In other LHC news, there has been an ongoing campaign to simulate the bad interconnections that are still known to be there in the machine, and these simulations have led to much more confidence that the potential dangers in the case of a quench are understood. The simulations show that operation at 3.5 TeV/beam should be safe, but going up to 5 TeV/beam without fixing the interconnections (which requires warming up the sectors involved) still seems risky.

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8 Responses to Latest From the LHC

  1. P says:

    Hi Peter,

    When they say 3.5 TeV / beam, does that mean the energy for each beam or is the collision energy (i.e, 2*3.5 TeV) ?

  2. Peter Woit says:


    They plan to run at 3.5 TeV/beam, for a total collision of energy of 7 TeV. This is 3.5 times the Tevatron energy (1 TeV/beam), half the LHC design energy (7 TeV/beam).

  3. Steve Myers says:

    I caught part of a History Channel piece on LHC. They did show the soldering technique (quickly, though). Looks like pressurized hot box. Might be worthwhile to see the whole show.

  4. zanzibar says:

    Here’s the lastest news from CERN:

    Headline: “Swiss atom lab: Physicist held on terror links”

    (Nothing but the facts ma’am).

  5. zanzibar says:

    And from the BBC

    Headline: “‘Al-Qaeda-link’ Cern worker held”

    Apparently, the suspect is a 32-year old non-CERN collaborator on LHCb.

    He and his brother were arrested in south-east town of Vienne (100 km outside of Geneva).

    CERN is cooperating with French authorities in the investigation.

  6. BDO Adams says:

    I’m sadden they haven’t fixed the interconnections yet. If there going to have to reheat and recool each section before they can get to 5 GeV. The LHC isn’t going to get full power in 2010 at all. Is it? Still there is be plenty of room for new particles from 1 to 7 TeV.

  7. Peter Woit says:

    The LHC definitely won’t get to design energy (7 TeV/beam) in 2010, they may or may not get to 5 TeV/beam. In any case, even the starting 3.5 Tev/beam is 3.5 times the Tevatron energy, so a new energy range will be begin to get explored. In any case, my guess is that much of 2010 will be taken up with understanding the behavior of the machine and of the detectors, getting both working reliably.

  8. Rob says:


    Unfortunately it’s not that simple. When you consider the production of new particles at a collider you need to consider the collision as two incoming partons (quarks & gluons), not two incoming protons. Even though the Tevatron has a center of mass energy of roughly 2 TeV, it can only produce particles of roughly a few hundred GeV. This is because it is extremely unlikely for a parton to have a large fraction of the total energy of the proton.

    If you take into account the fact that the tevatron has recorded roughly 100 times more data than the LHC will be able to record the first year you’ll quickly come to the conclusion that nothing new can be discovered the first year. For example: The tevatron has a greater chance of creating a 500 GeV resonance in 5 inv fb than the LHC does (at 7 TeV) in 50 inv pb.

    Unfortunately it’s going to be a few years before the really interesting results start coming in.

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