LHC Luminosity passes 10 inverse microbarns per second

The Large Hadron Collider has passed a new luminosity milestone with a peak of 10.1/μb/s ( or 10.131 Hz/cm2 or 0.32/fb/year) recorded in the CMS detector. This was achieved at the start of a run with a new filling scheme using 50 proton bunches per scheme today. This figure is one tenth of the target luminosity for the end of this year that is needed to get them ready for collecting 1/fb during 2012.

2 Responses to LHC Luminosity passes 10 inverse microbarns per second

  1. Luboš Motl says:

    Good progress! If 10% were added every day, the luminosity would go up 17-times every month. Too bad it doesn’t work in this way.

    • Philip Gibbs says:

      Yes, that would be nice, but it is not the way they have been progressing.

      What usually happens in practice is that they double the luminosity, then they spend a week checking the beam tune, the dump, loss maps, damping curves etc. When they are sure there is nothing new going wrong they are ready for the next doubling. This process is also interupted by the need to test new injection schemes, etc. and by planned and unplanned stoppages.

      So this 10% increase was an exception. It may have been done partly to get the milestone. I think they are also trying to push up the bunch intensities a little. The nominal intensity is 110 billion protons per bunch, but they have been mostly running with only 90 billion because the beams are too unstable when they increase further. They need to fiddle with the damping and tune to improve it. The hump is also still there causing trouble.

      This was the best run yet with about 320/nb delivered.


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