Highest energy ever

By Daniel Holz | March 18, 2010 9:10 pm

At this very moment the LHC is busy trying to set a new world record. The goal is to achieve beams circulating at 3.5 TeV, bringing collisions between protons to 3.5+3.5=7 TeV center-of-mass energy. This would be the highest particle energy ever accomplished by humans (nature somehow routinely manages to produce cosmic rays at energies 8 orders of magnitude higher!). This news is hot off the press: we had a talk today by Lyn Evans, and he gave us the latest update. He should know what’s going on, since he’s project leader of the LHC. Evans shared some entertaining anecdotes from the last few years of commissioning, including:

LHC tunnel (photo by Peter McCready)They use superfluid helium to cool the superconducting magnets. One of the many weird properties of this stuff is that it has zero viscosity. Which means that, if there’s any sort of hairline fracture anywhere in the 27 kilometer long tunnel, the stuff comes spewing out, and very, very bad things happen. Every component, every joint, every one of the tens of thousands of tiny connections has to be perfect. It is this sort of failure which brought the machine to its knees shortly after commissioning, over a year ago.

The magnets are kept very, very cold; the superfluid helium is at 1.9 Kelvin (-271 Celsius), or a couple of degrees above absolute zero. We’re not talking a little vial in a laboratory being kept at this temperature. We’re talking many thousands of tonnes of magnets, kept just above absolute zero (using 96 tonnes of liquid helium). As things cool down, they naturally contract. The decks on bridges do the same thing, hence those serrated grills at the ends of bridges to absorb the expansion and contraction due to weather (if you’ve ever motorcycled across a bridge, you know exactly what I’m talking about). There are equivalent serrated joints in the LHC beam pipe to ensure that it doesn’t contract and rip open upon cooling (which, needless to say, would be bad). But upon reheating a section of the LHC, it turned out some of these devices left little fibers in the beam tube. Not good. How to find them, without ripping open the entire collider (costing millions of dollars and setting the project back precious months)? They ended up blowing a ping pong ball (with electronics embedded) down the tube, and tracking where it would get stuck. A simple, elegant, cheap solution to fix a multi-billion dollar enterprise.

For a while during the construction they ended up with roughly a billion dollars worth of superconducting magnets being stored in a parking lot at CERN. For reference, this is comparable to the entire GDP of many small countries (Bhutan, Guyana, Burundi, etc.), sitting out in the rain and snow. Big science.

Hopefully sometime in the next few days they’ll be running at 3.5 TeV. Apparently it’s been slow going because the system to prevent catastrophic quenching of the magnets (which is what “broke” the machine previously) is on a hair-trigger, setting off all sorts of false alarms (and when it goes off it quenches the magnets [in a controlled manner]). You can keep track of the progress on the LHC webpage (clicking on the image of the ring gives real-time data on the temperature of the magnets). Although this would be the highest energy ever achieved, it still doesn’t significantly surpass the science reach of Fermilab’s Tevatron, since the latter has run for many years (albeit at a lower energy of 1 TeV+1TeV). Both energy and (integrated) luminosity matter in this game, and the Tevatron has gotten more than 8 inverse fb (femtobarns; one of the best units in all of science [think “there’s no way to miss it, it’s as big as a barn”]). The LHC is shooting for 1 inverse fb. All being well, in a few months they’ll bump the energy up to 5 Tev on 5 TeV. This should significantly open up the scientific discovery space, and could conceivably kick off the next revolution in particle physics. Exciting times!

  • Charles Kessler

    Yes… exciting times. Jumping into the great unknown without knowing exactly what will happen as stated by CERN’s own physicists. Weird thing, how can they have done a safety report (LSAG) on the LHC when their physicists are clueless?

    CERN physicists quotes:

    John Ellis:
    “We don’t know exactly what we’re going to find, but we know whatever it is it’s going to be something new.”

    Brian Cox:
    “At every stage of und…erstanding the universe better, the benefits to civilisation have been immeasurable. None of those big leaps were made with us knowing what was going to happen.”

    “We know it will discover exciting things. We just don’t know what they are yet.”

    “The LHC is certainly, by far, the biggest jump into the unknown.”

    “We know it will discover something because we have deliberately built it to journey to uncharted waters.”
    http://www.popsci.com/scitech/article/2008-09/defense-lhc (page 2)

    November 2009, CERN Director for Accelerators, Steve Myers stated “The LHC is a far better understood machine than it was a year ago.” If CERN understands the LHC better now compared to their understanding in 2008, wouldn’t that make the 2008 LSAG safety report invalid?

  • Andy C


    I was a little surprised to see the statement “in a few months they’ll bump the energy up to 5 Tev on 5 TeV”. I was under the impression that they would spend the next 18 months at 3.5 TeV on 3.5 TeV. Have I missed something? Thanks.

  • http://muon.wordpress.com/ Michael

    Hi Andy,

    you are right, the LHC most likely will run with 3.5 on 3.5 TeV. As Daniel writes, though, the machine physicists will try to go to 5 on 5 later on, only if they are convinced it is safe to do so. The Director General has put a priority on accumulating 1 fb-1 for the sake of the science. With 1 fb-1, the LHC experiments will be sensitive to some models of new physics beyond what the Tevatron has achieved.


  • Pieter Kok

    Charles Kessler, what are you worried about? Nature routine produces much more energetic collisions, and were still here. Unfortunately, we cannot study those collision because they occur at random places. That’s why they built the LHC. Cheer up!

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  • student

    It’ll be running at sqrt(s) = 7 TeV until 1 fb-1 is collected or winter of 2011, whichever comes first.

  • Jimbo

    This should create fireworks, as 6-6.5 Tev is QG territory.

  • http://www.math.columbia.edu/~woit/blog Peter Woit

    The idea of possibly going to 5 + 5 TeV was abandoned in late January, on the grounds that the problematic splices in the machine make this too dangerous. Instead, they will run at 3.5 + 3.5 TeV until some point in 2011, then shutdown for at least a year to fix the splices. Back probably in 2013 to try for 7 + 7 TeV.

  • http://danielholz.com daniel

    Lyn was quite clear that the goal is to bump up to 5 + 5 TeV in the coming months (assuming all is going well at 3.5+3.5). Given that he’s in charge of the whole project, I’m inclined to believe that that’s the plan. But it’ll all depend on how the machine is behaving.

  • http://muon.wordpress.com/ Michael

    Hi Daniel,

    that’s very interesting – that Lyn made such a strong statement in public. He is in charge of the LHC accelerator, so his word carries a lot of weight, as you say. But let’s also remember who is the head honcho there – Rolf Heuer, who presumably approved today’s press release: “Once 7 TeV collisions have been established, the plan is to run continuously for a period of 18-24 months, with a short technical stop at the end of 2010.” Trying to go to 9 or 10 TeV would mean an interruption in this long, continuous run. Let’s see how things go, and how the machine people judge the robustness of the machine. I would be very happy to see at least a little data at 10 TeV, for sure!


  • Alexander Lobkovsky

    I have always wondered why the cosmic rays cannot be used for high energy experiments in orbit. Is it that the luminosity is too low so we’ll be waiting until the cows come home for the Higgs up there?

  • John

    Alexander: in a word, yes!. In fact, even with the LHC at 7 TeV or even 14 TeV it could be years before we are able to see a standard model Higgs boson, if its mass is about 120 GeV.

  • Marc


    Luminosity of LHC (approximately): 10^30 per cm^2 per sec

    Luminosity of 1 TeV (center of mass) cosmic rays hitting Earth: 10^-2 per cm^2 per sec.

    ’nuff said.

  • Aaron Sheldon

    Running a ping-pong ball down the pipe sounds really similar to running a pig down a high pressure oil and gas pipeline.


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  • Ellipsis


  • Kessler

    Pieter Kok, cosmic rays are hitting stationary particles, and when that happens any dangerous phenomenon created gets easily bounced into space at an insane speed, that’s why we’re still here. In the LHC, protons will be colliding with each other at the same speed, so any dangerous phenomenon created will have a velocity of zero, so gravity takes over.

    CERN’s defense is that micro black holes wont grow but will evaporate due to an unproven theory, Hawking Radiation. What’s bad about this theory, is not only that it hasn’t been witnessed, but was admitted to be in error by Stephen Hawking in 2004. What if it’s completely wrong?

    CERN’s back-up defense when their Hawking Radiation is outed as fraudulent due to their past statements of calling it a process when this theory hasn’t been proven, is that if the LHC managed to create stable black holes that Earth’s gravity captures, their growth is no call for alarm due to the existence of Neutron Stars and Brown Dwarf planets, like our planet is one. Last I checked, Earth isn’t, and has a weak gravitational pull CERN admits could capture these slow moving, or dangerous phenomenon with a velocity of zero due to collisions within the LHC at the same speed and strength. If you collide two balls on a pool table at the same speed, directly at each other, see how fast they bounce each other away… they wont but stay put at point of collision since they will have a velocity of zero.

    CERN’s old defense is that these particles over 100 of thousands of times hotter than the heart of the sun after collision is equivalent to two colliding mosquitoes. Problem with this defense which tries to downplay risks is that no proof has been provided to back the mosquito comparison claim. Google it and you will not find any admission of visual proof of this claim, just wild guesses that’s it equivalent, and since their the experts, they want us to leave it at that.

    CERN’s admission to particle collision being 100 thousand times hotter than the core of the sun: http://public.web.cern.ch/public/en/LHc/Facts-en.html

    To read about the mosquito comparison, visit the link below. Scroll down to the topic “Microscopic Black Holes” and read it’s third paragraph:

  • Kessler

    Back in the 1950’s CERN was thinking ahead. To avoid being stopped from performing any dangerous collider experiments in the future, they had countries sign an immunity contract in 1955, 1972, and again in 2004. CERN knew these collisions dangerous consequences back in the 1950’s and still do till this day. Why would they need immunity if it was safe?

    I’m assuming the United States signed one of the older contracts since they didn’t sign the 2004 revised version.

  • Brian137

    Charles Kessler,
    Well, at the very least, we will have resolved the Fermi Paradox.

  • Jennifer West

    Yes indeed, particles colliding with equal and opposite velocities only produce a puddle of particles standing still, then falling under gravity’s influence. A well documented fact.

    That was irony. Could we please please have commenters pass an undergraduate physics degree filter, or a common sense filter, or both?

    Just in case that commenter is not a troll (I would not pass a common sense filter for this assumption), I’d like to mention that the laws of physics give conservation of energy and momentum, which can easily hold provided the sum of momenta in all directions is conserved. Zero total momenta initially means the sum of all final momenta must be zero, not that each individual momentum must be zero.

    Back to studying.

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  • bw

    I think the Alpha Magnetic Spectrometer experiment (run by MIT’s Sam Ting) is still scheduled to be launched on the penultimate Space Shuttle flight in July 2010

  • Martin

    Hi Daniel, I’m echoing Michael at # 10. I pounced on Mark Trodden’s post before about machine announcements. It may be easy to trust what an important source says, but based on my experience and looking at the run schedule, 5 on 5 is not very likely. I’m always afraid of statements like these before they become official announcements.

    It will likely be 7 TeV center of mass until otherwise noted.

    Rather than making lots of enthusiasm for what can be achieved, I’d leave it to have official articles published and announced, and making references from these instead of having “inside word.” When you tell the world we’ll be having 10 TeV collisions, and people wait for it and it doesn’t come for a year, it looks a little bad for the experiment- “How come they can’t deliver when they said they could?” On the other hand, the same people may not know the difference betwen 10 TeV and 7 TeV physics signals (well, that could be true for the experimenters – this is new territory after all!)

    But any publicity is good publicity!

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  • JD


    Hawking didn’t admit that black holes don’t radiate away energy and evaporate. He admitted that Hawking radiation contains the information that went into the black hole in the first place. Please get your facts straight before fear-mongering.

    More information is available in Leonard Susskind’s book:


    (which is an excellent read for laypeople, but which seems very basic even to this junior undergrad.)

  • JD

    Also, I have to echo Jennifer West’s comment. Unlike politics, high-energy physics doesn’t care about equality. Some people’s opinions ARE worth more than others, because they’ve spent years studying the phenomena in play. It’s great that people are getting interested in frontier science, but it’s bad that they’re taking misinformation as truth.

    The LHC is a tool which whill help us determine which, of many different models, is the correct one. Those models have been published many, many times. They’ve been read, studied, criticized. If you’re going to say that the LHC is endangering the Earth and you want to be taken seriously, do as the high-energy physicists have done: show your work. So far, I’ve never seen anyone in the LHC-is-dangerous camp do that, but I’ve seen plenty of people show that it’s safe.

  • Jesse M.

    Kessler, it’s unlikely micro black holes will actually be created in these collisions in the first place, that would only be possible in models with large extra dimensions which are a speculative extension of string theory (and string theory can itself be used to derive the prediction of Hawking radiation as I understand it). But more to the point, even if micro black holes are created in the LHC, that would imply micro black holes are also being routinely created by cosmic rays whose energies can sometimes be even higher; so even if Hawking radiation is wrong, there must be some physical factor that prevents such micro black holes from eating the Earth, since if there wasn’t the Earth (and every other massive body in the universe, like stars) would have been eaten long ago! That logic seems pretty irrefutable, can you suggest a reason micro black holes created by the LHC would behave any differently than those created by high-energy cosmic rays?

  • jimvj

    Please dispel my ignorance about this:

    why is it not feasible to use the so-called high temperature superconducting wires made by American Superconductor (www.amsc.com)?

  • Kessler

    JD, where did I write that Stephen Hawking admitted Hawking radiation doesn’t radiate away energy and evaporate? Want to reread what I wrote instead of making up things. You are a college student, right? I wrote that he admitted it to be in error in 2004, which he did, and I provided a link to his admission. I later stated in my previous comment that the Hawking radiation defense is fraudulent if LHC cheerleaders call it a process when this theory hasn’t been witnessed in nature. If you want a theory like this to stand until proven, don’t call it a process without visual proof or it will come off as fraudulent. Common sense my dear fellow.

    Yes, Jennifer, please study… or maybe don’t. Common sense doesn’t come from being book smart. You either have it or not going in. Think of the money you’ll save! Anyone with common sense can read what I wrote above, so please use whatever intelligence you have to counter my argument intelligently without resulting to a Rovian Swift-boat attack like before. You embarrassed yourself!

    What I stated above was dangerous phenomenons being created, not what you stated below in Ann Coulter style:

    Jennifer (The Brain) West:
    “Yes indeed, particles colliding with equal and opposite velocities only produce a puddle of particles standing still, then falling under gravity’s influence. A well documented fact.”

    Anyone with enough common sense, interested in physics, have more than likely seen images taken of collisions. Particles flying in all directions… but there’s a chance some particles, not all, might not have enough escape velocity, maybe even zero.

    Jesse, CERN has admitted to this on their site “Those produced by cosmic rays would pass harmlessly through the Earth into space (due to faster than light cosmic rays hitting stationary Earth particles), whereas those produced by the LHC (head on proton collisions at the same speed) could remain on Earth.”

    Jennifer, now I’m not saying from one collision all those particles will stand still, but some might as CERN stated. Is CERN also wrong, a troll on a global scale against their own experiment due to this admission on their site? Doh!

    Jennifer, you’ll be alright. Save your money while you can!

    Above CERN’s admission is based on a hypothetical, which all their theories is based on.

    From Merriam Webster website:

    theoretical –
    3: existing only in theory : hypothetical

    hypothetical –
    2 a : inference from defective or presumptive evidence b : a conclusion deduced by surmise or guesswork c : a proposition (as in mathematics) before it has been proved or disproved

    That’s why the 2008 LSAG report is BS. It’s based on unproven theories (hypotheticals), to justify the machines safety. Still waiting for someone to show me the visual proof of colliding mosquitoes equaling the energy of a proton collisions over 100 of thousands of times hotter than the core of the sun. Jennifer, anything in your books on this?

    JD, you seem worse off than Jennifer, but you can prove me wrong. Visual proof to the colliding mosquitoes equaling the energy of proton collisions! Who done it? Where? How was it recorded? Not just a link to CERN’s site stating it’s the same. Real visual proof of the energy of colliding mosquitoes! Link please.

    That’s the challenge, folks.

    Jennifer, JD… time to turn those wheels in your head. For real this time! Don’t hurt yourself. :-)

  • here

    Well a 2.5mg mosquito going 2km/hr should have about 2.4 TeV when it hits anything, right?

    Am I doing my math right?

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  • Jennifer West

    I knew it. I’m laughing, at me, for not filtering myself. C’est la vie, back to books, thanks for the post D. and for the futile support JD…

  • cryo peon

    @ #29 – Just guessing that hi temp SC is not available in the enormous continuous lengths that magnet windings require. Also many of those type of wires do not allow for the bend radii (ie: tight bends) needed to curve around the magnet core. (But it sure would be easier to operate at warmer temps!)

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