Thursday, September 16, 2010

Visit to CERN

Last week, the CERN Book Fair give me the opportunity of a short trip back to CERN. I had been there a few times in 2000/2001, working with the Geant4 collaboration and contributing snippets of computer code to this huge simulation package, and I really enjoyed to visit CERN again, alas for a much too short stay.

Back then ten years ago, we could visit the LEP detectors in their caverns, and now, the LHC is running - but actually, these giant changes are nearly invisible on the Meyrin site of CERN:

There is the dark dome of the CERN Globe looming in the background, and the blue thing on the lawn is a LHC magnet, but otherwise, not much has changed. Unfortunately, the beautiful terrace of the cafeteria was a construction site, and the dusty glass display with Tim Berners-Lee's original web server had vanished from the side wing of the restaurant.

I remember that back then, I could stroll around a few of the older experimental halls, so I had the naive idea that I could try and find the famous hydrogen bottle that feeds the LHC. But of course, as the machine is running, there is no access to the accelerators: Defense d'Entrer/No Entry.

Instead, I walked to the Computer Centre, where we had our temporary offices when collaborating with the Geant4 group.

The stairs in the entrance hall lead to a visitors gallery, which allows a great view into the Computer Centre's huge machine hall:

Downstairs, next to the user helpdesk, there is now a small exhibition of historical computer hardware: magnetic tapes, giant floppy disks, clumsy looking equipment:

And there I did spot it again: The black NeXT workstation, the very first web server:

It seems that a web server was expected to be always available right from the beginning: With a red pen, Tim Berners-Lee has written a warning note on the NeXT:

This machine is a server. DO NOT POWER IT DOWN !!

Coming back to more recent times, Sabine told me of a talk she had heard just last week on ATLAS results, and of an ATLAS web page with plots and papers presented in talks during this summer.

I did browse around a bit, and while I do not want to say anything about the physics discussed in the papers, I realized that they nearly all quote a Geant4 paper on which I am a coauthor. Great, I thought, that should boost the quotation statistics - and then I realized that I am a coauthor on a "Topcite 1000+" paper!


  1. Very nice, Stefan, thanks for the tour. Too bad you couldn't see the world's most famous hydrogen bottle, maybe they're mad at you for exposing the "low tech" source of the LHC's protons. :-)

    Congrats on that 1000+ citations paper. I have a question though. With 125+ authors, how the heck can 125 people write a single paper? I am 100% sure every name was important in contributing, but ever try to get three people to agree on a single point of contention? And they have 125 ??

    I'm not complaining, the system is what is is, mostly I find it amusing, so I'll close with a question:

    HOW LONG has this super-author listing stuff been going on, is it a "CERN Thing" or is it international, and was it imported into Physics from another field or is it homegrown?

    OK, that was 3 questions, sorry. (One sentence though)

  2. We see two proofs of space alien visitation:

    1) Centre de calcul = 16 bytes, Computer centre = 15 bytes. The fonts are identical, yet the phrase with fewer bytes is linealy longer. Alien science!

    2) An LHC lawn magnet brazenly chumming for future alien visitations.

    The Thing From Another World (James Arness as the carrot), "Watch the skies, everywhere, keep looking! Keep watching the skies!" The true nature of axion telescope CAST is now very clear. "8^>)

    (Thermite on ice really does explode high order, via a BLEVE. How did they know? Alien science!)

  3. Hi Steven,

    It's not that 125 people actually WRITE the paper. They work on parts that are essential to its content. The long collaboration lists come with large experiments and involved software; basically it's an expression of increasing complexity. It's not exclusively a CERN-thing, there are other large collaborations, though CERN is an extreme. I don't know how long it's been going on, it will have been a gradual increase. I've seen long author lists also in some areas of biology, but it's mostly homegrown. Physics, and esp particle physics, just happens to be an area where experiments are very large and thus are collaborations. Best,


  4. Hi Stefan, if you come back, you can book a tour via the official CERN service and specify that you want to go see the LINAC. That's the first stage in the acceleration and it is where the hydrogen bottle of your other post is. Visitors can almost see it (the red flashy one which is on show is fake, but the real one is just behind). By the way, do you know how much would the LHC take to empty such bottle (assuming it's 1kg) if running at full power? About 1 billion years.
    Marco (proud CERN guide)

  5. Hi Stefan,

    Thanks for the virtual tour of CERN, a place I’ve always wanted to visit. All that dedicated computing power they have there is impressive and yet one tiny NeXT facilitated the platform that hosted the software which began the WWW. It has one to consider how the significance of things as being related to their magnitude most often rather than their effect. That is when the LHC at CERN runs its brief span of usefulness to be shut down and almost forgotten, the WWW will still be here as a side benefit with few will ever recognizing as what be its source. When looked at this way it’s hard to say what distinguishes big science from small as one never know where the journey will take you. It has one to wonder what other things might come out of all this other than those we expect.



  6. Ah, thank you, Bee, that explains it. Well hopefully, the list of collaborators won't grow as large as the number of people posted in credits of a Major Motion Picture (including the moose handlers in Monty Python and the Holy Grail). If I didn't know better, I'd think half the people on the planet were involved in making a single film!

    So your gist is that given the Complications (not just Complexity) of a single run or series of runs, at least a hundred if not more are involved. I guess that's good and I understand now. Better to give credit where credit is due than leave someone out who would then take up valuable managerial time having to listen to their complaints?

    For comparison purposes, Bell Labs in the 1980's (back when it was owned by AT&T and was hot!) had many papers with as many as 5 or 6 "authors." Typically, one person actually set up the experiment (and instructed those who ran it), and wrote the paper as well. He would be listed first. His boss (a.k.a. William Shockley) would review and edit the paper, and be listed second. The third person would typically be the in-house guy who developed the experimental apparatus. The fourth person would be the technician who actually ran the experiment, and the 5th person would be the technician who processed the newly grown semiconductor chip so actual tests could be run on it (usually by the first person) and results obtained thereby. The last two couldn't explain the paper with their names on it to save their life, but the experiment would not be a success without them, as they were the only 2 of the 5 NOT to suffer from "The Pauli Effect."

    And that's just for a technologically brand-new one square centimeter chip! So I can see in the proton train wrecks that are particle accelerator experiments many more would be involved.

  7. Yes, reading author lists can be tricky. It depends a lot on the field. For example, when I made my PhD the deal with the author lists was that the 1st author was the one who actually did the work, the following ones made contributions in declining order, and the last person on the list was the one with the grant (who, more often than not, hadn't even read the paper). The field that I now work in, author lists are mostly alphabetical, unless there's a very fresh student, who might be made first author to demonstrate he's the one who did the work. Best,


  8. Oh marco...

    1 kg of H_2, MW = 2.01588, at 22.414 liters/mole STP, 24.465 liters/mole at 25 C, is 496.06 moles or 12,136 liters at ambient temperature. (Ideal gas. Use the van der Waals equation for higher accuracy. a = 0.2452 bar-liter^2/mol^2 and b = 0.0265 liter/mole)

    A 1A gas cylinder 9x56 inches has an internal volume of 43.8 liters. A kg of hydrogen therein would then be at a pressure of 277.08 atm or 4073 psi - about double the commercial fill pressure.

    We state with definitive assurance that the CERN's little hydrogen bottle does not hold a kg of hydrogen. Its fill may only be good for a few thousand years (diffusion as a virtual leak, too). It thus requires emergency ISO 900x extensive reviews and documentations for in use suitability and mean time between failures.

    Shut down the LHC! Shut it down RIGHT NOW or management will be sad.

  9. Hi Steven,

    the question of authorship in large collaborations is a very good one!

    Actually, as far as I can see, the list of authors of this Geant4 paper includes everyone (in alphabetically order) who was, or had been, at the time of publishing a member of the collaboration and contributed to the code.

    Geant4 is organized by a core group of scientists who are on the staff at CERN, and collaborators come from institutes from all over the world (well, probably mostly from CERN member states). The whole project is organized in "working groups", who take care of specific aspects of simulations, such as "Geometry", "Hadronic Physics", "Photons", ...

    The actual writing of the paper was done by one or two people from each of these groups. So, I cannot point to one specific phrase or plot in the paper and say: This in mine!

    Actually, most experimental papers in high-energy physics work along the same lines: everyone in the collaboration is on the list of authors. Check out, for example, this recent PRL of the ALICE collaboration (it's open access) - the list of authors takes three pages, and CMS and ATLAS are even larger collaborations. It's not easy to say who contributed what...

    Cheers, Stefan

  10. Thanks again, Bee. Yeah, I like the idea of the youngest person getting the most credit, provided of course they actually did the most work.

    There is definitely something to be said about us older folks (Stefan, Bee, not you) helping the young-uns getting a good start in life, as well as the whole "27 is THE age for fresh ideas" thing, although there are many exceptions that blow THAT out of the water.

    Having said that, if we were to take 1915 and transport it to "convention" in 2010, how many (and whom) would feel justified to have their names added to Einstein's Theory of General Relativity?

    Marcel Grossmann, for starters. Who else?

  11. Hi Stefan,

    Sorry, we posted at the same time so I didn't see your response to this thread, or Uncle Al's either.

    Stefan, in no way shape or form do I wish to give the impression that any name on that list of "authors", including your own, do not deserve to be there.

    Quite the contrary. I believe a paper or report should list ONLY THOSE who contributed, not one person less nor one person more, and I take your word for it that every person listed deserves inclusion.

    My final point is good news, that Humanity has come a LONG way from the days of Thomas Edison. Amazing as he was, he took a LOT of credit from what was essentially tons of collaboration. Well, he had a ego. OK. But, still.

    The current convention strikes me as probably better than the old, my only caution being let's not get carried away, as I previously stated, as in the film industry.

    As Sargent Phil said in "Hill Street Blues": Be careful out there.

  12. Hi Marco,

    if you come back, you can book a tour via the official CERN service and specify that you want to go see the LINAC

    thanks for this tip, I didn't know that this is possible! That's a great idea! I hope I'll have an opportunity to come again, and then perhaps for more than just one day...

    Cheers, Stefan

  13. Hi Steven,

    concerning credit, there comes a real drawback with the custom to give authorship to the collaboration as a whole.

    A senior physicist at CERN told us that he is often asked to nominate young physicists for stipends or prizes, but that can not do so, because the collaborations are too big, contributions of single scientists are hard to discern, and the record of published papers isn't helpful either...

    Cheers, Stefan

  14. Err..., Uncle Al, I apologize: the info I have from the guide's service is that the LHC would take 1 Byr to use 1 kg. The assumption that that quantity could roughly fill a large bottle was mine. Sorry, I'm a theorist. Sorry also that your corrected computation shortens significantly the time at disposal for people to visit CERN before it all runs out.

  15. Good read on "Academia":

    "A Life Decoded"/Dr. Craig Venter

    "While authors fret about their words being stolen, scientists worry about the theft of their ideas without attribution. My first encounter with this form of intellectual appropriation came as my mentor lay ill in the hospital, and Jane (not her real name) decided to use this opportunity to take over my project -- by removing my name and Kaplan's from the cardiac center grant and substituting her own. The cardiovascular team assumed it had been done with our permission, because Kaplan was obviously too ill to handle this burden.

    We discovered what happened a month or so later when the program head, John Ross, sent me a copy of the cardiac center proposal as a courtesy. when I found Jane's name instead of my own, my brain almost exploded. Had Kaplan betrayed me for the benefit of another scientist? I rushed down the hall to his office, threw the grant on his desk, and shouted "What the hell is this?". Kaplan was unaware of the switch and was equally outraged, and when he calmed down, he argued that an important official's career could be jeopardized by the affair, an outcome Kaplan did not want for various political reasons. I was young, naive, and not the least bit satisfied or placated by his logic.

    Then Nate told me how he, too, had been a victim of intellectual theft early in his career. After he had written up his discover of coenzyme A with Lipmann for publication in the Journal of Biological Chemistry, Lipmann sent a draft to a senior colleague to review. They heard nothing in response, but in the meantime the journal sent Lipmann a manuscript to review: It was Kaplan's and Lipmann's own paper on coenzyme A, with their names removed and replaced the name of Lipmann's colleague. Lipmann called the editors of JBC and got the authorship restored. The paper became famous, contributing to Lipmann's being awarded the Nobel Prize"

    Although Kaplan argued that the "truth always comes out in the wash", I still believe that fraud should not be swept under the carpet for the good of the scientific community. Something much greater is at stake than individual reputations -- the credibility of science itself. I certainly felt that the bad guys had won when Kaplan told em a few days later that my grant was going to be funded via Jane: I should have felt good about my ideas being validated, but found it hard to do so when they had been appropriated by someone else"

    Dr. Venter left Academia for NIH, then Industry (Celera & JCVI).

  16. Hi Uncle & Marco,

    It's true that typically the steel containment bottle required roughly is 100 times heavier than the hydrogen it contains; just one of many reasons hydrogen fuelled cars remains at least for now as still impractical. Then again if CERN were to use the recently developed Class IV containers a relatively small bottle could hold more than a kilogram. It’s all a mute point however as the average useful life of a collider is not much more than a decade for which the gas on hand should appear as being overkill if anything:-)



  17. Hey Marco,

    It seems the demons do not have as much sway on the inevitable destruction of any moment? The destructive power to change things, from the inside/out while that angel rests on one's opposite shoulder.:)

    Angels and Demons

    If we could assemble all the antimatter we've ever made at CERN and annihilate it with matter, we would have enough energy to light a single electric light bulb for a few minutes.

  18. To understand the importance of this discovery we need to have a clear idea of what is meant by "matter". Particles are not sufficient to constitute matter; we also need "glues". With electromagnetic glue we can make atoms and molecules; to make the nucleus, we need protons, neutrons and nuclear glue. To make antimatter requires antiprotons, antineutrons and nuclear "antiglue"; but we also need to know that nuclear antiglue allows these constituents of antimatter to stick together just as protons and neutrons do to form matter. A fundamental law is needed that establishes the existence of nuclear antiglue that is exactly identical to the nuclear glue in matter. This fundamental law is missing. Why antihydrogen and antimatter are different

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  20. Hi Steven,

    I’m aware that upgrades have extended some of the collider’s life spans, yet this is still limited by the energy levels each can explore, with this being dictated primarily by their sheer size. I remember reading once that if we wanted to actually explore directly the energy levels associated with Quantum Gravity this would require a collider track ring circumference larger than our solar system. As for the Tevatron its fate now hangs in the balance while a decision is being awaited of the Physics Advisory Committee's proposal to extend its operations into 2014 in the hopes that perhaps they might beat the LHC to the confirmation or exclusion of the Higgs, although it’s stated as in the effort to compliment CERN’s effort. None the less as far as I can ascertain an commonly available bottle size of hydrogen is more than enough even with such extensions.


  21. "The first type IV hydrogen tanks for compressed hydrogen at 700 Bar (10000 PSI) were demonstrated in 2001." Call an ambient bar an STP atm. A type IV 1A gas cylinder with 43.8 liters volume holds ~2.76 kg H2 with pneumatic energy storage (one liter-atm is 101.325 joules) of ~3.1 MJ, 3/4 kg of TNT exploded. Hydrogen's J-T inversion temperature is -71 C. It heats when it expands, not cools.

    Gasoline's enthalpy of combustion is -48 kJ/g. The type IV 1A cylinder suffers wasted 85 ml of gasoline burned for compression energy. Its contained enthalphy of combustion is 391 MJ, 8.15 kg gasoline, 10.87 liters, 2.87 gallons of gasoline. The H*Y*D*R*O*G*E*N car!

    Marco, Uncle Al greatly respects and enjoys theorists! Models' empirical application needs real world trim. The Eöt-Wash group has the finest vertical torsion balances on Earth examining pablum. Eöt-Wash must examine test masses outside physics' founding postulates. Euclid cannot be falsified within Euclid, even though Eucld is egregiously incomplete (e.g., elliptic and hyperbolic geometries; Thurston).
    Two parity Eötövs experiments. The worst they can do is succeed.

    Those who do not respect the real world end up rebrazing thousands of 8700+ amp joins. Quis custodiet ipsos custodes? Entropy.

  22. Hi Uncle,

    Well this is the contradiction of Plato, as his answer to ” Quis custodiet ipsos custodies “ [who will guard the guards themselves] was they must be made to come to believe a “gennaion pseudo” [a noble lie]. The fact is science as a philosophy by its very nature demands transparency, where no untruth can be allowed to survive; so if the impossibility of Maxwell’s demon be false science will not be denied:-)



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  24. A bit off topic, sorry, but ...

    Bee (or Stefan), The Shape of Inner Space by Yau of Calabi/Yau manifolds fame has hit the bookstore stands and the reviews are nothing less than 100% positive (check out Not Even Wrong for example). It only has 12 reviews at amazon for example and they're all 5 stars. I've never seen that before, wow. Have you?

    Anyway, since we all love your book reviews, I am curious if you intend to read and comment on it. It would be cool if you did, I'm thinking.

  25. The Guardians were to be men of Gold....while the stratification of society were assigned their metal attributes?

    The Noble lie would be to uncover that Lincoln meant something more as to the use of crucibles mentally used, were to find that perfection could be more then the guardians of society, but more consternation for the truth of character?

    The oligarchical society is the demise of democracy gone to far. An unruly mob?

    Maxwell confirmed Thomson as the source of the word demon, and explained the demon's purpose.

    Concerning Demons.

    1. Who gave them this name?


    2. What were they by nature?

    Very small BUT lively beings incapable of doing work but able to open and shut valves which move without friction or

    3. What was their chief end?

    To show that the 2nd Law of Thermodynamics has
    only a statistical certainty.

    James Clerk Maxwell
    Plato made clear that merit and not heredity defined the gold man and that gold could be found in all parts of society.

    There be Dragons-
    Terra incognita and Corinthian bronze


  26. Hi Steven,

    I have no intention of reading the book. Best,


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  28. Simply because I have like 3 dozen books on my reading list already and the topic doesn't sound interesting enough to add it. I can't read all of the books in the world.

  29. Oh, goodie, Bee! you didn't say why you wouldn't. That's a puzzle. May we guess?

    1) Bee doesn't like string theory, which she thinks this is about.

    Well first, I have no idea of your opinion about ST (and no, the book is about Mathematics in spite of its title). I suppose I could find out if I read back all 4 years of your blog. I'm 75% against the theory as explaining reality, but I do find the mathematics of it intriguing. For right or for wrong, it seems to have attracted some of the world's finest minds. For example, David Gross gets paid something like 300K US $ to study and promote it. The NON-Anthropic kind in Gross' case. The kind without a big blanket over it.

    2) It's simply not in your area of specialty.

    I'm going to go with this one as most likely, because as finite beings, we have only so much time to read only so much. Totally understandable if so.

    3) You've already commented on Calabi-Yau, and have nothing to add, IYO.

    That would be fine, too.

    In any event, and if you don't mind :-), back on topic:

    Hi Stefan,

    In the post, you wrote:

    the dusty glass display with Tim Berners-Lee's original web server had vanished from the side wing of the restaurant.

    Egads and crikey, mate! Has there been a theft?! If so, where are the security cameras when you need them? Is somebody nappin' on the job?

    Or maybe it was put in the basement by a maintenance crew sometime? Hmm, another puzzle. Like the cold case of Linda Dirac, Paul Dirac's stepdaughter, who vanished in Vermont a long time ago. The world is full of mystery, yes?

  30. My apologies to Bee, I deleted and edited so my response came after her response, instead of the other way around. I may be in need of an editor more than Seth Lloyd, sorry.

    Well OK, I can understand the large book reading list thing. Then there's all the papers to read! Best of luck in keeping up, and thanks for replying.

  31. Hi Steven,

    Has there been a theft?! If so, where are the security cameras when you need them? Is somebody nappin' on the job?

    No worry ;-)... The exhibit was just moved from the main building to the computer centre - it's the one I have photographed.

    Cheers, Stefan

  32. Hi Plato,

    You said: Plato made clear that merit and not heredity defined the gold man and that gold could be found in all parts of society.

    True indeed and yet Plato’s lie although accepted by many of lesser metal never was by most of those who would think themselves to be gold, which is to indicate a lasting just society can never be secured by a falsehood no matter how well intended. On the other hand if we take the path dictated by science, to have doubt only satisfied by reason in having things made transparent, as to be understood, then as the truth is revealed so is its good. This is essentially the extension of Pirsig which is to realize that the good is only one of the aspects of quality as well as its truth and beauty, so those who would be true peoples of gold can be inspired to be such by reason rather than myth.

    “Plato claimed that even though this tale would be literally false, if the people believed it, an orderly society would result as it would explain the origin and importance of the three classes. Thus it would serve the same function as other creation myths.

    -as taken from Wikipedia





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