Today the Large Hadron Collider has taken another step up in luminosity by increasing the number of proton bunches per beam from 1092 to 1236. The first run at this new intensity equaled the previous luminosity record. They may beat it in subsequent runs by pushing up the bunch intensity. One more step up is required to reach this years maximum possible bunch count of 1380 bunches per beam. It may be too late to reach that step before the next technical stop.
The advance comes at the end of a tough week with only one run during a period of five days. At least that one run was itself a record with integrated luminosity for a single run of 47.7/pb in ATLAS. For CMS the total delivered was 46.3/pb but they issued a special note to say that they had also recorded 44.3/pb, more than the entire amount recorded during 2010.
The main reason for the delay this week was problems with cryogenics caused by clogged oil filters and possibly worsened by a lightning strike and/or an industrial strike. When any one of the 8 major cryongenic plants fails it can easily take two days to get it fixed and return the superconducting magnets to their working temperature of 1.9 degrees Kelvin. There were two such outages this week with this record run in between.
Update 27-Jun-2011: The situation has improved in the last few days culminating in a run today lasting about 20 hours that delivered a record 62/pb. The luminosity was still above half its peak value at the end of the run demonstrating just how good the luminosity lifetimes are. The next run will attempt 1380 bunches, the maximum possible with 50ns spacing. They have just one day left before machine development time takes over, followed by a technical stop.