I’m on pixel shift in the ATLAS control room at the moment. We’ve had a very successful run, with stable LHC beams for about the past 12 hours. The luminosity of the detector is another step forward, because the past two nights have seen more bunches per beam than ever before. The lifetime of the beam is also excellent. You can see below that the luminosity of the beam has only been decaying very slowly for the past 9 or 10 hours.
The LHC reports that, after the dump, they will fill the LHC for another physics run. I’m actually not sure why they’re dumping so soon, given that it will likely take a few hours to dump and refill, and the beam still has a lot of oomph in it. Some ideas off the top of my head: maybe the LHC experts think it’s best to do the dump and refill during the day shift; maybe they think that the luminosity in the next run can be made even better; or maybe they want to get more practice and collect more data about the start of physics fills in this configuration. But the bottom line, for me and for ATLAS, is that when they dump the beam, we reset our detector and get ready for the next physics run.
Ok, gotta go, it’s time for the beam dump!
LHC Status from July 31, 2010 at 11:49 AM
nice,
what is the current integrated lumi ? 1pb-1 ?
regards
It must be nice to do something record breakng every single night…
This sounds like it is going great, are you in the energy realm where you might find new physics yet or does it still need to be ramped up even more?
Paolo: our latest plot shows about half an inverse picobarn for ATLAS, 513 nb^-1:
http://atlas.web.cern.ch/Atlas/GROUPS/DATAPREPARATION/PublicPlots/DataSummary/figs/sumLumiByDay.png
We have another very good run that just finished, and I bet those numbers aren’t included. (Although they will be; that link is updated regularly with the newest current version.) You can see the plot is climbing quite rapidly; we could reach 1 pb^-1 quite quickly if the LHC did physics runs continuously. Of course, our goal for 2010 and 2011 is to collect at least 1 fb^-1, a thousand times more. That means that the priority for the LHC is to work on increasing the luminosity still further, rather than giving us physics data at the current highest rate.
Kate: Our center-of-mass energy is 7 TeV and holding; we’re going to stay at that energy for all of 2010 and 2011. That energy is 3.5 times higher than the Tevatron, the previous record-holding hadron collider, so it’s certainly possible to find new physics. But we probably need to collect more data! You can’t really quantify the exact chances of finding new laws of physics, but with the 1 fb^-1 mentioned above, there will be a lot of things we can see if they’re “out there.”
Of course, in the longer term, it will help us tremendously to collect data at even higher energy: starting in 2013, we’ll be running at about 14 TeV.