by Pasquale Di Nezza. Published: 25 November 2011

The data taking currently taking place, using the heavy ion (lead-lead) collisions, lasts for a month (until 8th December). November is the golden month for ALICE and the efficiency has to be as high as possible.

The data taking started on the night between November 5-6 when test beams were injected and brought to collisions. The number of events were few, around 10,000, but extremely useful for debugging the complicated chain of events which goes from the detectors to storage and then to the grid of computers for analysis.

After a few days of commissioning, the LHC was ready to start the normal operation and one record after the other was achieved: high intensity, high refilling efficiency, high beam quality. In the ALICE Interaction Region (IR2), there are 336 + 336 interacting bunches and the peak luminosity reached the highest value ever observed at LHC for HI roughly, ~11 times higher than the one reached last year.

Of course ALICE is always following the records. At the moment, four times the statistics collected in 2010 has been collected and evaluated by the “Data Quality”.

As an example, up to today ALICE has collected and prepared for analysis 11 million of the very interesting central events, 6.5 million high-pt events triggered by the electromagnetic calorimeter and 14 million muon events.

We are running the whole experiment with an efficiency that is increasing overall. For instance, this night, we collected 92% of the delivered luminosity by LHC. Already several physics programmes can be fulfilled with the data collected and ALICE proceeds to access to the most rare events that transcend the frontiers of the physics knowledge in this interesting and challenging field of physics.