Beam Circulating in LHC Again!

By John Conway | November 20, 2009 9:43 am

09:37 PST: Like many of my colleagues, I’ve been eagerly awaiting word that the LHC has successfully threaded the proton beam around the whole ring. In recent days they have gotten it half way around the 27 km circumference, and within hours, they should be able to circulate it and I assume “capture” it with the RF, which creates stable bunches in the synchrotron. Everything has gone very smoothly to this point, so I expect success shortly!

Once beam has circulated stably in both rings, some time next week the LHC team will attempt to collide protons at the injection energy of 450 GeV (a total center of mass energy of 900 GeV). While this is much less than the Tevatron is colliding presently, it could provide some sorely needed initial data for the detectors to do timing and calibration of the various subsystems. There will even hopefully be a few collision events recorded with clear “dijet” structure – collisions where quarks and/or gluons inside the protons hit head on and effectively bounce sideways into the detector, giving two back-to-back collimated sprays of particles. Pictures of such events will be great to see, at long last!

You can follow progress live on twitter: and I will update this post as I learn more.

10:32 PST: The LHC has gotten beam around clockwise, to Point 6! Woo hoo!

10:45 PST: Magnet quench – should be recovered soon…

11:25 PST: Beam has reached Point 7!

11:30 PST: Point 8! Next beam will be sent past Point 1 where ATLAS is…

11:39 PST Beam all the way around the ring! WOO HOO!! It’s baaaaaack! The LHC Page 1 display shows that the injection probe beam made it more than once around the machine:


11:54 PST: Next goals: do the same with the counterclockwise beam. Will they attempt RF capture tonight? Trying to find out…

13:11 PST: Turns out (no pun intended) they decided to go for RF capture of the clockwise beam rather than probe counterclockwise. They are up to 10 million turns with the RF on! Fantastic!

13:30 PST: Having captured the beam for several minutes, the LHC will now switch to counterclockwise.

14:53 PST: About to go for a full orbit of the counterclockwise beam…done!! Now to RF capture!

15:30 PST: Counterclockwise beam is RF captured! The LHC is operational…colliding beams within a week? Stay tuned.

CATEGORIZED UNDER: Science, Technology
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  • Gavin Flower

    Congratulations to the LHC and all who sail in her…

    Great news indeed!!!

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  • Blake Stacey

    CERN is Tweeting that cavities are switched on and beam is captured. US LHC team is pleased.

  • Gavin Flower

    20 Nov, 22:33, Beam 2 Knocking on the Door

    Beam 2 is now at the “TDI”.

  • efp

    Off topic:

    A thumb, middle finger, and tooth removed from the corpse of Galileo Galilei, lost for a century, have been recovered. The Istituto e Museo di Storia della Scienza di Firenze are planning to put the relics on display next year.

    I think the middle finger should be installed facing the Vatican.

  • graviton383

    We all have our fingers crossed! Maybe we can have an EXTRA special Thanksgiving on Thursday…

  • Brian137

    Whoopee! You go, protons!

  • Jeroen Holthuis

    OMG! The guys of CERN really need someone to design a proper user interface! Such an important experiment, such a bad interface. I am for hire. Please contact me.

  • Darlene

    Well, that’s good news. NFL’s Former Rookie of the Year, Hugh Douglas, was never worried about the LHC:

  • Matt S.

    I would guess stability is the highest priority of the interface, everything that doesn’t directly add to functionality just poses an extra risk (that’s just my guess, but it would seem plausible).

  • marc
  • guy

    If they wanted to make a real breakthrough they’d collide a cheeseburger and a taco. THAT, my friends, would be progress.

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  • Kaiser

    Can’t wait to watch it at 100% I hope it´ll be soon

  • taueret


  • rogerdee

    The moment of TRUTH is upon us! Will the LHC find the Boson? …and the Creator will laugh at our foolishness.

  • rogerdee

    Because the “foolishness of God is greater than the wisdom of Man”. True Science and Faith do not conflict as so many Christians fear, because those two spheres of thought address disparate issues. The realm of faith and reason are merely the foundation when man exceeds the bounds of known FACT.
    But the realm of THEORY is only that…what might be possible to unlock the origins of life and the Creator of the Boson can only be FAITH.

  • Creator of the Boson

    Shh, Roger! The fermions might hear…

  • graviton383

    450 x 450 collisions on Thanksgiving??

  • God




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