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Second Snag This Week Could Delay LHC for Weeks
Posted by
Soulskill
on Fri Sep 19, 2008 11:01 PM
from the unfortunate-but-to-be-expected dept.
from the unfortunate-but-to-be-expected dept.
sciencehabit writes "After a transformer failure earlier this week, the Large Hadron Collider has hit another snag — and this one is much more serious. As Science reports, 'At least one of the LHC's more than 1700 superconducting magnets failed, springing a leak and spewing helium gas into the subterranean tunnel that houses the collider ... How long [repairs take] will depend in part on how much of the LHC must be warmed to room temperature for servicing. If it's only a short section, the repair could be relatively quick. But the machine is built in octants, and if workers have to heat and cool an entire octant, then the cooling alone would take several weeks."
Reader Simmeh contributes coverage from the BBC. We recently discussed the transformer malfunction at the LHC, which was a smaller problem and has already been fixed. Update - 9/20 at 12:52 by SS: CNN reports that the LHC will be out of commission for two months.
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[+]
LHC Shut Down By Transformer Malfunction 293 comments
Ortega-Starfire writes "A 30-ton transformer in the Large Hadron Collider malfunctioned, requiring complete replacement on the day the LHC came online. No one at CERN reported any problems, and they only released this data once the Associated Press sent people to investigate rumors of problems. I guess it's hard to just sweep a 30-ton transformer breaking under the rug."
[+]
LHC Offline Until April 2009 (Or Longer) 298 comments
rufey writes "The recent problems at the Large Hadron Collider will now keep it idle until spring 2009. The official press release is here. The LHC went offline due to a suspected failure in a superconducting connection, which overheated and caused around 100 of the LHC's super-cooled magnets to heat up by as much as 100 degrees. This resulted in the accidental release of a ton of liquid helium. The process required to repair the failed superconducting connection involves weeks of warming up the affected area from -456 degrees Fahrenheit to room temperature, and then several more weeks to cool it back down after the repair is made. The total amount of time to do this will spill over into CERN's scheduled winter maintenance/shutdown period, which is partly done to save money on electricity during the period of peak demand."
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Messin' up committee's schedule (Score:5, Funny)
The Milky Way Darwin Award Committee has to wait a bit longer before awarding the little blue ex-planet.
Re:Messin' up committee's schedule (Score:4, Funny)
If you're not nice, I'll make pro-creationism jokes next.
Parent
Were Nielsen and Ninomiya correct? (Score:5, Interesting)
Re: (Score:3, Interesting)
We've never isolated a single quark, yet we sure know a helluva lot about them.
Also, for an interesting and somewhat related topic, check out the wikipedia page on Quantum Suicide and Immortality [wikipedia.org]. It's an interesting thought experiment for many-worlds interpretation.
Or, similarly, observer-selection of broken LHCs? (Score:5, Insightful)
Parent
Re:Or, similarly, observer-selection of broken LHC (Score:5, Interesting)
http://en.wikipedia.org/wiki/Many-minds_interpretation [wikipedia.org]
Only minds that exist can observe; only minds that have not been destroyed by the LHC can exist. So, if the LHC really destroys the earth we'll keep observing it not functioning correctly.
Parent
Re: (Score:3)
> So, if the LHC really destroys the earth we'll keep observing it not functioning correctly.
Until it does, in fact, start working and destroy the earth. After all, while all the many-things ideas are fun to discuss, they only say that if the LHC necessarily destroys earth when it works, there will be branches that will have observed the LHC never working and that these will be the only ones with humanity intact.
We could very well observe the destruction of the world, but we can rest assured that some o
Re:Give me a bag (Score:5, Funny)
When _I_ turn something on, I set it up completely first, leaving only one final connection incomplete. That connection is made by an enormous knife switch, which I throw to the dramatic dimming of lights (managed by my assistant; my invention is of course on another power source entirely), sparks, and the scent of ozone. THAT is how you turn something big on.
Parent
Re:Or, similarly, observer-selection of broken LHC (Score:2)
And one great way (mentioned in the links) is to kill yourself, and see if that merely excludes from your observation any world in which you'd be dead.
Hey, just puttin' it out there.
That's how... (Score:2, Funny)
Argh, Matey! (Score:5, Funny)
Thar she blows, ye scalleywag... doewn beluw deck she's spewin colder then the centre o' hell.
Mark me wards... there's trouble brewing... somethin strange and black. Beware, I say... beware!!!
That's a lot of helium... (Score:5, Funny)
All I could envision was a bunch of physicists coming out of the tunnel squeaking like chipmunks.
I have nothing to contribute but a cheap laugh and for that I am sorry.
Re: (Score:2)
Liquid Helium Piping (Score:5, Interesting)
Re: (Score:2)
Re: (Score:2)
Re:Liquid Helium Piping (Score:5, Informative)
There is not just one line. There are 6 lines as far as I know. They transport superfluid helium as well as warm helium. Here is a paper about the cryo system:
http://accelconf.web.cern.ch/AccelConf/e96/PAPERS/ORALS/THO04A.PDF
Anyways, they are now investigating with a remote inspection train that can travel in the LHC.
Paper accessible here:
http://accelconf.web.cern.ch/accelconf/p07/PAPERS/MOPAN076.PDF
Sorry but I am going to an anonymous coward -- but clearly, this post comes from CERN...
Parent
So what? (Score:5, Insightful)
Re:So what? (Score:5, Funny)
Parent
the octant? (Score:5, Funny)
oh i know this level
just beyond the dead space marine after you open the first door (watch out for the imp sniping at you from above) there's a false panel marked "UHC" (not "LHC") on your left. shoot that with your pistol and it opens. but shooting your pistol will wake a cacodemon further down the hall
easy
Protracted Development Schedule (Score:2)
Cyro status: sector 34 at 20K-80K (Score:5, Informative)
You can look at much LHC status online, including detailed cyro status. (I'm not giving the URL, so as not to Slashdot that server. You can find it if you really care.) Sector 34 of the LHC is at sector 34 at 4.5K-20K, instead of down below 4.5K where it should be. One of the magnets quenched and went normal, and much of the energy in the magnet is dumped as heat. Then the liquid helium boils to a gas and blows out through relief valves. But the sector hasn't been brought up to room temperature, so they apparently think they can fix the problem without major work on the magnet.
Some of the cyrogenic magnets gave serious trouble last year, but apparently it's not as bad this time.
Re: (Score:3, Informative)
Pardon me, but have you or whoever modded that up any clue about that? It could be that way, or it could be that a missing magnet will cause the beam to veer off course, hit where it shouldn't and create a major fuck-up. These aren't exactly guide rails, they're the only thing keeping the particles in their place.
Maybe this is just the Universe's way of saying... (Score:3, Funny)
STOP!!!!!
Is anyone listening?
Ok, one thing for the naysayers... (Score:3, Informative)
I would expect at least a douzend of failures and faults of that magnitude until full power is reached.
Its just too complex.
And about the "expensive!!!1" aspect: A few months delay are so much cheaper than spending twice as much before so try to get everything 200% perfect. And even then things might go wrong.
Even in a tiny normal synchrotron, shit happens. At the ALS in Berkelely they managed to detonante a main PSU because they only tested them one at a piece, and when build in they had bad crosstalk. Beam was down for several weeks.
At the SLS in Villigen, even months after the full ramp-up beam instabilities or drops happened on rather regular basis.
Such things happen.
This is what a 'quench' is... (Score:5, Informative)
If you are not familiar with superconducting magnets, then some of these terms may seem a bit mysterious. So, here goes...
A superconducting magnet is essentially a big coil of superconductor. Initially, you put current into the superconductor to build up the magnetic field. You then 'join the ends' of the superconducting loop, so the current circulates endlessly, and the middle has a constant magnetic field.
There is a lot of energy in the magnetic field. An 11-tesla magnetic field has about the same energy per unit volume as TNT. Worse than TNT, there is no rest mass to the 'explosive' so all the magnetic field energy would be dumped straight to the surround. The surround is already under a lot of tension due to the magnetic field, so the magnet would blow apart spectacularly, if it wasn't properly designed.
The magnet has a link in the superconductor which is heated to drive it 'normal': this is used when the magnetic field is being built up. This link usually has a great big conventional shunt resistor in parallel with it with great big heat sinks, and this arrangement is usually on the top of the magnet. If the helium level gets low or something else funny happens, the hope is that the coil superconductivity will go at this point rather than anywhere else. The magnetic energy, instead of getting dumped into the magnet's structure, gets dumped into this shunt resistor. It may glow yellow, and boil off lots of helium, but the magnetic field can collapse over a few seconds rather than instantly, and won't release an electromegnetic pulsed that might set off a chain reaction with the magnets next door.
What has happened here is that the safety system has gone off in one of the magnets just as it ought to. I expect they will inspect the shunt assembly to check nothing has scorched when all the energy got dumped, and also to try and find out why it did. However, with luck they can get it all going again without interrupting the vacuum.
Re:This is what a 'quench' is... (Score:4, Interesting)
To add to this pretty good explanation, quenching is a normal part of "training" a SC magnet. Basically, when the SC coil is wound, there are slight imperfections that prevent a maximal field from being obtained. So you pump a shit ton of current through the magnet after cooling it for the first time till it quenches. As you put field, you actually are changing the winding configuration ever so slightly, as the field generated by the magnet can actually exert on the force wires containing the current. This process is repeated several times to maximize the attainable field, and make it homogeneous as possible, etc.
The only other problem is that unplanned quenches can also damage the magnet. That is unlikely in this case, but I have a dead hulk of a 9T in my lab to prove that it can happen. To this day, I don't know what went wrong, but my guess is that there was damage at the point that current enters and leaves the system during field changes. Hopefully this is not the case at the LHC, and they can be back up and in business ASAP.
Parent
In Soviet Russia... (Score:3, Funny)
What does LHC Stand for again? (Score:3, Funny)
LHC = Leaking Helium Coolant
Quite appropriately named uh?
Doomsday Device (Score:5, Interesting)
This makes me think of the great SF story "Doomsday Device", by John Gribbin (Analog, Feb. 1985 -- unfortunately not available online, AFAIK). In that story a powerful particle accelerator seemingly fails to operate, for no good reason. Then a physicist realizes that if it were to work, it would effectively destroy the entire universe, by initiating a transition from a cosmological false vacuum state to a lower-energy vacuum state. In fact, the accelerator *has* worked; the only realities the characters experience involve highly unlikely equipment failures. (Thus, a many-worlds physics is shown to be correct.) It's further revealed that the world has been "anthropically steered" in the past by arranging for it to be destroyed when things are not going well.
Black Holes and God Particles (Score:3, Interesting)
Just once, I'd like to see a report on the LHC that didn't call the Higgs Boson the "God Particle", and didn't talk about crackpot fears of mini black holes. I mean, we don't follow every report from the Mars polar lander or rovers about the "Canals of Mars were once thought to carry water", do we?
Re:sabotage (Score:5, Insightful)
I would be surprised. Shit happens.
Parent
Re: (Score:3, Interesting)
No, but I'd be a bit surprised if it was sabotage.
Re:sabotage (Score:5, Funny)
Parent
Re:sabotage (Score:5, Insightful)
I would have been amazed if a structure as complex as this worked the first time the switch was thrown. Think about how simply enormous the LHC [wired.com] is. It has miles of wire, gigantic magnets that have to be perfectly synced and placed with amazing accuracy. It's not like LHCs are turned out every week. Gigantic super colliders are HARD to build.
They'll eventually iron out all the problems and can proceed to cause the world to end.
Parent
Re:sabotage (Score:4, Insightful)
"It cost 70 bazillions of dollars to build, and now it's BROKE? What, they never actually DID anything with it yet either? What a joke" they'll say.
From the perspective of the non-geeks, this thing is a perpetual money sink, a haven for nerds to tinker and fiddle with things that require unending tinkering and fiddling by design, with only a carrot of some potentially really great stuff that just might some day dribble out of the thing.
Think about it, whoever wrote the grants or whatever that got them all that money is a genius - "Ummm yes, I need 70 bazillion dollars. What does it do? Ummmmm, yes, it will have the potential to reveal to us the HIGGS BOSON! Yes. HIGGS BOSON. What good is the HIGGS BOSON? Ummmm, yes, the HIGGS BOSON promises to reveal to us the very SECRETS OF THE UNIVERSE!
Go LHC! As a geek myself, I say we need more of these things!
Parent
Re: (Score:3, Funny)
>What does it do? Ummmmm, yes, it will have the potential to reveal to us the HIGGS BOSON! Yes. HIGGS BOSON.
Wot?
All this money just to peek at Miss Higgs Bosom?
Re: (Score:3, Interesting)
Absolutely. My wife is an astronomer. At the observatory she's at (Apache Point, as recently featured on Mythbusters) most of the instruments that they mount on the telescope require cooling either through liquid nitrogen being poured into reservoirs twice a day or through electronic CryoTigers. They just came out of shutdown (an extended maintenance period when they close for most of August to perform heavy maintenance) and a month after coming out of shutdown one of the CryoTigers developed a fault, ca
Re:sabotage (Score:5, Funny)
Fuck, I can't even get Hello World to work on the first compile most of the time.
Parent
Re:Is this indicative of something? (Score:5, Informative)
Yes, because taking nearly 30 years to build this was rushing.
Calm down, one of the magnets quenched. When that happens, it gets REALLY hot and things break. They knew it could happen.
Parent
Re: (Score:2, Insightful)
Re: (Score:2, Interesting)
Well I have to admit that the LHC has been built a lot better than I had even hoped. Working at CERN I can access the LHC status pages and the internal reports on how far they have gotten and to be honest before the breakdown they had gotten things done that everyone assumed would take 3-4 weeks.
And the big startup of LHC on 10th of September which went with only a few minor glitches was an extremely gutsy thing to do. I mean you have hundreds of reporters there when you attempt to power the thing on and do
Re:Is this indicative of something? (Score:5, Insightful)
Parent
Re: (Score:2)
I meant it more as a joke than anything--next time, I've got to keep my mouth shut. :-)
Re:Is this indicative of something? (Score:4, Insightful)
And even if it does turn out to be completely useless for physics, I would have much rather have seen my US tax dollars be wasted on something like a particle collider than how they've been wasted in Iraq. Money spent on science is almost never truly wasted.
Parent
Re:Is this indicative of something? (Score:5, Informative)
Parent
Re: (Score:3, Informative)
Having worked on one of these, two failures this early on is par for the course. There's a lot of work to be done even after the thing is build and initial testing is done before it's stable and working (and even then, most particular accelerators are only somewhat "stable" with very heavy maintainance).
Re:ohno! (Score:5, Funny)
For the slashdotters who haven't yet seen the CERN webcam images of the leak occuring:
http://www.cyriak.co.uk/lhc/lhc-webcams.html [cyriak.co.uk]
Parent
Re:good grief (Score:4, Funny)
No! Don't you see!? This is quantum immortality at work! The universe in which the LHC works is the one in which WE ALL DIE!
</paranoid>
Parent
Re: (Score:3, Funny)
I just keep having this image in my head of two of the technicians for the LHC wandering through the innards of the thing, when one suddenly looks at the other and says, "Aw crap! A Helium leak!"
Sounding, of course, like a chipmunk.