Quick LHC update

Since the LHC restarted after the last technical stop it has added about 210/pb to the integrated luminosity. In the last 5 days since returning to 1380 bunch fills more than 150/pb have been added which brings them back to the previous good production rate of about 30/pb per day.

New records for peak luminosity were set last night with 1.75/nb/s during stable beams and 1.8/ns/s during the adjust mode of a run that was dumped before stable beams. Before the technical stop the record was 1.28/nb/s so significant luminosity increases have already been achieved. This has been mainly due to better beam emittance at about 2.4 um in the lastest runs. The bunch intensity is still being held at 120 billion.

There are many problems causing beams to be dumped including UFOs, cryo, vacuum, RF and power glitches. However it has been possible to recycle and return to stable beams relatively quickly to keep the data flowing. Unless they can improve the stability they may have to reconsider the plan to increase bunch intensity because that would mean more cryogenic outages that can stop the runs for one or two days at a time.

Steve Myers will give a status report at EPS in a plenary session on Wednesday that is due to be webcast.

7 Responses to Quick LHC update

  1. Bornerdogge says:

    Didn’t you mean bunch intensities of 120 billions, not 200?

  2. carla says:

    The main problem seems to be vacuum activity which they don’t fully understand at the moment. Maybe with more experience they can get to grips with the problem.

    I’ll be willing to bet that within the week, they’ll have discovered something and it’s full steam ahead.

  3. algernon says:

    I see both detectors are going to hit 1.5/fb recorded, but the question is: given that we won’t have conclusive Higgs results in time for Lepton-Photon (except for some extra exclusions above 200 GeV), what is gonna happen next? When are they going to publish updated results after LP?

    I see some CERN seminars mid September but then, basically nothing until January. Do we have to wait that long? They’re gonna produce no less than 1/fb/month after all…

  4. carla says:

    Does anyone know where I can see what emittance value they’re using when injecting?

    • Philip Gibbs says:

      I don’t know if we can see it in real time but Myers gave a plot of emittances for recent fills in his talk today

      • carla says:

        Do you have a link for the webcast? If not, have they modified their plans for increasing luminosity, given the problems they’ve been having with increasing bunch intensity from 1.2 x 10^11 and vacuum activity?

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