Second Snag This Week Could Delay LHC for Weeks 160
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.
Were Nielsen and Ninomiya correct? (Score:5, Interesting)
Re:sabotage (Score:3, Interesting)
No, but I'd be a bit surprised if it was sabotage.
Liquid Helium Piping (Score:5, Interesting)
Re:Were Nielsen and Ninomiya correct? (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.
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.
Re:Is this indicative of something? (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 a full scale test of almost all components LIVE. That's gutsy. What's even more amazing is that it actually worked! They got the beam around both ways and by the evening (when the press had left already) they already had stable beams which did hundreds of orbits around the accelerator. Also being at CERN I can tell that the pre-testing they did before the big event was really marginal. The beam was only tested a few km along the tunnel in both directions, never too far so they were really treading on unknown territory.
I'd love to see some other huge experiment/production like that to show their results live in front of the world when they first start it :P
Re:Cyro status: sector 34 at 20K-80K (Score:1, Interesting)
As opposed to a quadrupole, which you use to focus the beam (at the loss of longitudinal focusing, since Liouville's Theorem applies and magnets are Hamiltonian processes). There's one main quadrupole after every three dipoles in the LHC.
Also there's even higher order and other special purpose magnets for fine control and other wacky stuff (beam dump, injection, etc).
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.
Re:sabotage (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, causing an instrument to warm.
When this happens, the instrument has to warm to ambient temperature (a full day), the CryoTiger has to be repaired (at least a day), then the instrument cooled again (another day). Instrument is out of commission for a good three days. The sad thing was that it was scheduled for a time-critical block, fortunately the weather was poor and they couldn't have used it anyway.
Monumental PITB. I can only imagine how much nastier it is with the LHC.
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?