This week the Large Hadron Collider has been demonstrating unprecedented success and exceptionally smooth running. When the present fill is terminated at around 6pm European time the collision data delivered this year will amount to 5/pb. This has been achieved in the space of just 50 hours with a total time in stable beams of about 32 hours. During that time they have only experienced two significant problems; one unplanned dump and a brief loss of cryogenic status. Last year when the systems were being commissioned it was normal for every other attempt to reach stable beams to fail for some reason. In comparison we now see almost every fill being completed with a planned dump and no problems. This bodes very well for the 2011 physics runs and the beam team must be very happy with the LHC today.
At the end of the present fill using 64 bunches they should have the all clear to increase luminosity again. I am told that previous plans to go up in three steps at 104, 152 and 200 bunches have now been replaced with a two step plan at 136 and 200 bunches. This will probably require switching from the present 8 bunch injection to 24 bunch injection. At each step they need to complete three fills totalling 20 hours of stable beams. The new goal is to reach last year’s highest luminosity in just a few days so that the schedule can be brought forward. According to the draft schedule of last week they had intended to do an intermediate energy run during April. The purpose of this run is cross-calibration between proton and heavy ion collisions which requires a proton run at the same energy per nucleon as used for the lead ion runs last year. If possible this will now be brought forward to complete it before the scheduled technical stop on 28th March.
There is one other chore that must be undertaken before serious proton physics data taking can begin. There will be a scrubbing run during the first two weeks of April to clear the collider of dust particles and other unwanted effects. As far as I know this will still proceed as planned. This leaves 7 weeks of data collection before the “Physics at LHC 2011” conference. They should be able to deliver as much as 200/pb (or even more) in that time if everything continues to run as smoothly as it has his week. That’s enough to significantly advance the ongoing searches for SUSY and other exotic physics.
Thanks to “pcatom” on the lhcportal forums for the detailed info
Update: A new run with 136 bunches is now in progress giving a peak luminosity of 150/μb/s