LHC update: 3 August 2012

The LHC had a rocky recovery from the extended luminosity calibration runs, and on Saturday 21 July a number of fills were lost due to beam instabilities. The situation was stabilised by temporarily backing off increasing bunch intensity and the next 24 hours saw a record delivery of around 260 pb-1 to each of the ATLAS and CMS experiments.

This good performance continued the following week with around 55% of the time spent in "stable beams". Over 1 fb-1 was delivered to ATLAS and CMS. This was despite some timeouts for access and operational development. Peak luminosity is down about 10% from the highs earlier in the year, but the LHC is regularly enjoying long fills in the 12 to 15 hour range. Here we are seeing the benefits of the extensive consolidation work to mitigate the effects of radiation to electronics in the LHC tunnel and the continuing efforts to improve overall reliability.

Combining data runs from 2011 and 2012, LHCb crossed the 2 fb-1 mark last Monday. The experiment is about 2 days away from collecting 1fb-1 in 2012 alone. ATLAS and CMS are closing fast on the 10 fb-1 mark for 2012 (both on 9.8 fb-1 at the time of writing).