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What's the word from the innards of CERN?
I've seen a few things mentioning that the beams are circulating, are they just still doing low level calibration/checking, or have things moved on a bit?
What's the word from the innards of CERN?
I've seen a few things mentioning that the beams are circulating, are they just still doing low level calibration/checking, or have things moved on a bit?
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Things have moved on a bit, but not much - to me, it seems that the main thing going on is a lot of champagne drinking...
We've been colliding very low-luminosity beams (low luminosity means not many protons in the beam) at the injection energy, which is 450 GeV per beam. So basically we've just been storing beams in the LHC that have been accelerated in an earlier synchrotron in the chain of LHC pre-accelerators, and then crossing the beams every now and again.
We've also used the LHC to accelerate the beams a small amount (up to 540 GeV), but have yet to cross any of these slightly higher-energy beams.
Some people have been trying to analyse the very early data to see how the detectors are doing. Amusingly on one mailing list, some guy is claiming he has "rediscovered the kaon" in one of the events (it was originally discovered in the 1940s), so it looks like the detector I work on is performing well enough to do this, at least!
I think the priority right now is trying to improve the beam lifetime. The LHC is a storage ring as well as an accelerator, and should eventually be able to store 7 TeV beams for ~10 hours. Currently I think we're only managing to store the beam for about 40 minutes, and that's only at 450 GeV per beam. Once beam lifetime is improved, we'll move on to trying to take the "Highest Energy Particle Accelerator" crown from Fermilab. Fermilab has 1 TeV beams, and thus 2 TeV collisions. We're aiming to exceed 1TeV beams sometime in december
There is more info on the CERN twitter feed: http://twitter.com/CERN
Oh, and I also posted some more info when we had the first collisions here
Last edited by Fraz; 24-11-2009 at 11:12 PM.
bsodmike (10-12-2009),chuckskull (11-12-2009)
ooh cheers Fraz
I didn't realise it could be used to store the beams as well, but thinking about it, it's fairly logical that it would be able to do that (accelerates it, then just keeps the energy cycling, like a giant centrifuge?)
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I love that we have a live one here... fraz... we love you
Originally Posted by Advice Trinity by Knoxville
+1 to that. It's fascinating stuff, please keep updating us Fraz!
It's at times like this I wish I'd carried on with physics after A-level.
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I feel it's time for me to throw in my usual joke:
http://www.youtube.com/watch?v=hBaaU1EUAtU
PHP Code:$s = new signature();
$s->sarcasm()->intellect()->font('Courier New')->display();
I misread the title..
I think this is so cool I have changed my name to Bruce Higgs-Boson.
(Thanks Evilmunky)
Eagles may soar, but weasels never get sucked into jet intakes.
Yeah, basically that's right. Right now, the beams aren't living very long because we don't have a tight enough control over them. But when we do have good control of the beams, the reason they will only lasts for ~10 hours is because we'll be crossing them at four locations on the ring every 25 nanoseconds. This slowly degrades the number of protons in the beam, until eventually we discard it and create a new one.
ooh cheers Fraz
I didn't realise it could be used to store the beams as well, but thinking about it, it's fairly logical that it would be able to do that (accelerates it, then just keeps the energy cycling, like a giant centrifuge?)
When we're running at full steam, the beams will consist of about ~3000 tight bunches of protons spaced 25 nanoseconds apart in time, with each bunch containing ~200 billion protons. Every time we collide the beam, roughly 20 proton-proton collisions will occur... so naturally the luminosity of the beam degrades over time because some protons are lost.
So... you see that there are a lot of protons in the beam, each of which has a lot of energy for something so small. To give you an idea, when things are at full power in a couple of years or so, each circulating beam would be capable of instantly liquefying 500 kilos of copper. So, building a beam dump that can absorb the beam if we need to get rid of it quickly is quite difficult... I think each one weighs in at 1000 tonnes and they have to be water cooled to disperse the heat quickly enough.
bsodmike (10-12-2009),chuckskull (11-12-2009),kidzer (01-12-2009),MaddAussie (02-12-2009),Stoo (25-11-2009),Zak33 (30-11-2009)
Pretty mind blowing thought that protons with such energy can liquify half a ton of copper!
just make sure you keep a handy crowbar
Don't worry, we're ready:
0iD (30-11-2009),alsenior (25-11-2009),Blastuk (02-12-2009),bsodmike (10-12-2009),chuckskull (11-12-2009),kasavien (25-11-2009),MaddAussie (02-12-2009),pollaxe (25-11-2009),steve threlfall (25-11-2009),Zak33 (30-11-2009)
Some very good pics of CERN stuff that I've just come across here:
http://www.boston.com/bigpicture/200..._ready_to.html
Colin Murray works there too?!
Those are some awesome photos
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