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LHC Offline Until April 2009 (Or Longer)
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."
I thought the absolute zero was at -273...ah, damn americans!
Say something meaningful--the magnets were about 2 degrees Kelvin.
you mean 2 Kelvin (since it is an absolute scale)
Last time I checked, LHe was about $5 USD a liter. A metric ton is 1000kg, and LHe's density is 0.125g/ml (wikipedia), which amounts to 8000 liters or about 40k. Considering that He is non-renewable, leaking out of the atmosphere, hopefully they were able to reclaim and recompress it.
Look at the LHC cyro status for sector 3-4. Average magnet temperature is now at 70K, and slowly creeping up to room temperature. Notice the expanded vertical scale on the graph. Compare with the other sectors, holding with liquid helium at 1.9K.
Warmup is slow. Cooldown is slower. Several kilometers of pipe and a hundred or so magnets are involved.
It's not that bad, though. It looks like they won't have to take magnets out of the tunnel for rewinding. That's a huge job. This is just a slow one.
They can warm up or chill down sector 3-4 during the shutdown period. The rest of the system would normally be cooled during shutdown anyway.
When they're using the kind of energy that knocks out country powergrids, then yes, it is a consideration.
The LHC cooling circuit has something like 400 tons of helium in it.
One ton missing sounds reasonable.
The cold doesnt matter, btw. Liquid helium has a really low heat capacity and evaporation enthalpy. A dewar full of liquid nitrogen spilled will do much more damage than 10 times the amount of helium, even if the helium temperature is lower.
And helium is not THAT expensive. At least compared to the other costs.
A physicists analogy is that a LN2 costs as much as cheap beer, while L He as much as good whiskey, per volume... (I once used 2000l of liquid helium in a single week because of a faulty magnet that couldnt be replaced during beamtime. Although that was of course recaptured. I hope they have options to do that in the LHC cave, too, even though the initial containment was breached)
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
I believe with all the problems they're having, the actual date when the high-energy collisions begin will be December 2012.
That actually is appropriate, though probably not in the sense that P means. The Mesoamerican calandar that 'ends' in 2012 is just the end of a chunk of a calendar, to be followed by another chunk, and another, etc. It is like New Year's Eve for us; the end of a cycle and an excuse to party. 2012 is just an excuse to party, Mayan style, ripping the hearts out of human sacrifices or however they celebrate it.
When the first collisions happen, that will be grounds for partying also.
Yeah I was wondering. Does it open the gates to the Dungeon Dimensions to let the creatures that live there in?
Let's just say you'd better have your Young Men's Reformed-Cultists-of-the-Ichor-God Bel-Shamharoth Association dues paid up.
You are in a maze of twisty little passages, all alike.
They are *quite* heavy in a gravity well.
There is a war going on for your mind.
For those of you who do not know, that is a Mark Twain quote (presumed to be, anyhow)
"When the end of the world comes, I want to be in Cincinnati because it's always twenty years behind the times."
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
Spacesuits operate in vacuum, which means there are almost no no particles around, so the word temperature does not make much sense there. Vacuum is an excellent insulator, so it is easy to keep them warm. It is a myth that you instantly freeze when exposed to the vacuum of space.
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