The Large Hadron Collider has reached its official 2010 target for peak luminosity of 100/μb/s or 1032/cm2/s . Massive Congratulations are due to all the teams at CERN who have worked incredibly hard this year to achieve this success!
This luminosity is 3.15/fb/year. The target next year is to collect 1/fb of data, but it is not possible to run at peak luminosity continuously so an extra margin is required. If they can run for 40% of the time during the running time allocated they really need peak luminosities of about 200/μb/s so they still have a little ground to make up.
The 100/μb/s has been reaches with 248 bunches by pushing to tighter emittances and better intensities. The next physics run will be with 300 bunches.
There are still three more weeks of proton running this year, so with the official target passed they can relax and use the time remaining for whatever seems most useful. That will include running to collect physics data before the winter break, pushing the number of bunches a little higher, and running various tests and scans that help them understand the machine better.
One last thing they might possibly try is something extra to improve luminosity. There are options to squeeze the beams to a lower beta* of 2m, or reduce the bunch separation to 75 ns or even 50 ns, but these might take time and result in less data collected for this year. If they don’t do these things now there should be time next year.
Whatever they, this year’s proton physics runs will be counted a great success.
Update (16 Oct 2010): In a short run last night with 312 bunches the peak luminosity was increased to about 135/μb/s. The filling scheme is 150ns_312b_295_16_295_3x8bpi19inj which means 312 bunches per beam with a 150ns minimum separation between bunches, 295 collisions per turn in ATLAS, CMS and LHCb, 16 collisions per turn in ALICE and 19 injections of up to 3 trains of 8 bunches at each go.
Tentative plans are to move to 360 bunches after three good runs at 312. Then they hope to try out a 50ns bunch spacing and 32 bunch injections so that they can go to 400 bunches or higher. They are also still hoping to collect 50/pb before stopping pp physics. Current total delivered is just over 20/pb. Whether they can get there, (or even go beyond) depends on how many running problems come up in the two weeks they have left, but with the goals for 2010 already met, anything extra is icing on the cake.