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Monica Dunford | USLHC | USA

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Wednesday Expectations

First beam is quickly approaching. For ATLAS. Actually several other experiments have already seen beam (it is hinted that CMS will see something today). But as ATLAS is the last experiment on the ring, it means that we have to wait until the 10th. It is annoying being the last on the ring sometimes.

For the 10th, the beam is only a single beam, so there will be no collisions. But it is still exciting all the same. And what can we expect to see in the detector with single beam? Two things.

One is ‘beam halo’ events. These are muons which have left the beam core and are moving along side the beam. The other is ‘beam gas interactions’ which are when one of the protons in the beam collides with some other particle in the beam pipe (the beam pipe is under vacuum but no vacuum is perfect). Even with these two types of events, we don’t expect to see a lot of hits in the detector. But even a few hits tells us a lot. Single beam is also very useful to help us establish our timing. This means determining when to read-out our electronics relative to when the beam bunch enters the detector. In other words, we won’t be sitting around, bored come Wednesday.

Someone once asked me what ATLAS planned to celebrate with. And the answer is… Champagne, of course. We even have it prepped and ready to go in control room (as seen here). The label reads ‘Break in case of collisions’. Not a problem.

Atlas celebrate


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19 Responses to “Wednesday Expectations”

  1. Jeff McBride says:

    Just want to say good luck, and I hope you get to break open that bottle on schedule. You all get to be in an exciting place at an exciting time, and I’m glad you’ve taken the time to share some of it here. Keep up the posts! Let us know how it goes.

  2. [...] a few more days until they start circulating proton beams at the LHC and my wife turns 50. [...]

  3. Luís Afonso says:

    One or two months ago I replied another post where I mentioned how frustrated I got every time the “switch on” date was postponed for some reason. I was explained that no one had ever built such a complex machine and it just took its time. I understand. But it was still frustrating. Not anymore! I guess congratulations are in order.

    I also read that the first collisions at full power are due somewhat before Xmas. Is that still on?

  4. Diels says:

    Yesterday I saw the newspaper and knew that at last it would begin.How excited!Good Luck! A lot of “Xs” are waiting for us!

  5. bart says:

    What an exciting time for particle physics. I am a layman with a keen curiosity for science in general and physics in particular. I don’t pretend to know the nuances of string or super string theory, but I read as much as I can (Scientifc American being my main source).

    I wish all of the teams at CERN the best of luck and I can’t wait for the first exciting results to be published.

  6. Kate says:

    But…you said above that ATLAS is a single beam and there WON’T be any collisions…so your champagne will sit undrunk, or will the LHCb kids sneak in at night and steal it?

  7. [...] Large Hadron Collider (LHC) at CERN, the world’s most powerful particle accelerator, will make its first attempt to circulate a beam (on September 10). Here’s a groovy rap featuring Alpinekat giving us a musical run down of [...]

  8. Paul says:

    Talking about expectations… I believe that the LHC will open a door to an extra dimension, (not the ones talked about in string theory); I am referring to a more abstract door leadind to a new level of awareness or consciousness. If we may picture the way we comprehend the Universe in three levels, we are about to enter the third level thanks to the experiments done in the LHC. The first level has been known since antiquity, namely the awareness of large objects, the ordinary objects surrounding us on a daily basis. Look around you, what objects do you see? This is what I call the First Level of Consciousness. By the way, I just saw a beautiful woman walk by, this is really an awesome level of consciousness. The Second Level began with the revolution of Quantum Mechanics in the 1920′s. It is the level of Probabilities and Uncertainty; where we are not passive observers but rather we influence the outcome of the experiment with our own very observations. This level was described by Niels Bohr in the following way: “It is wrong to think that Physics is to find out how nature is, Physics concerns what we can say about nature” and in the words of Heisenberg: “When one wishes to calculate the future from the present one can only get statistical results”. So, like I said before, we are about to enter a new Level of Consciousness or Understanding of our Universe. The LHC will help us enter this level. This level will definitely answer the question: Do we need new Physics? Is the origin of the Universe comprehensible? or is the Universe beyond synthesis? I am inclined to believe that the results will prove that the existence of the Higgs boson is beyond our present technology and that hadrons will be formed as a result of the mini black holes (these ones acting as gluons), but let me stop speculating for now and let the particles roll!

  9. jose says:

    good luck i hope everything goes as planned. cant wait to see video.

  10. [...] be clear. Tonight’s start-up is a symbolic event, not a physics event; as I understand it, the beam will only be circulating in one direction, so there won’t even be any collisions. Still, it’s a very important symbolic event! [...]

  11. Michael Kundu says:

    My family and I are waiting with baited breath – we wish everyone good luck on this precedent-setting effort. My two sons (13 and 14) are trying to explain the start-up – and the entire program – to their friends. AlpineKat’s rap helped, but if anyone can suggest another good source for middle-school students, please share!

  12. cori belanger says:

    Good luck to you all!! I cannot wait to hear what the findings are. This is very exciting, even for people that are not scientists. Blessed Be!

  13. Kevin says:


    the dawn of a new age for mankind indeed!

  14. Jacob says:

    awesome! good luck to you all. thanks for sharing this information and please continue to keep us posted.

  15. jasavi says:


    Caracas, Venezuela

  16. Ivan Szabo says:

    A new big step for the mankind!!!
    Keep the good work guys!!!!

    Santa Cruz, Bolivia

  17. Jason Gunnink says:

    So excited for you all! I am in the middle of reading Brian Greene’s book “The Fabric of the Cosmos” which has served as my first introduction to the concept of the Higgs field (amongst many other fascinating theories of particle physics). How exciting then to find the LHC now built and ready to prove it’s existence. I have to say it’s hurt my brain at times to read this book, but also gives me comfort that we really are making striking advances in this field. Best of luck to you on this amazing journey!

  18. Bo iddly says:

    Hey thanks for keeping us informed. Many congratulations to you!

    Bo Diddly

  19. My best regards goes to you.
    This is truly pushing the boundaries of our knowledge.

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