ALICE installs new hardware in preparation for the 2012 run

2011 was a fantastic year for the heavy-ion run at ALICE despite unprecedented challenges and difficult conditions. The data collected is at least one order of magnitude greater than the 2010 data. Thanks to a planned upgrade to two subdetectors during the 2011/2012 winter shutdown and a reorganisation of ALICE’s Physics Working Groups that should allow them to better deal with the greater challenges imposed by the LHC, the collaboration is confident that the 2011 run will allow ALICE to extend its physics reach and improve its performance.

Photograph of ALICE taken by Antonio Saba during this year's winter shutdown.

The annual winter shutdown has been a very intense period for the ALICE collaboration. In conjunction with the general maintenance, modifications and tests of the experiment, two major projects – the installation of 3 supermodules of the Transition Radiation Detector (TRD) and 2 supermodules of the Electromagnetic Calorimeter (EMCal) – have continued on from last year. These new supermodules will give the two detectors more coverage of collision events during the 2012 run. In addition, ALICE teams had to deal with technical issues that affected the filters of the cooling system of the Silicon Pixel Detector (SPD), some high-voltage discharges occurring in the Time Projection Chamber (TPC) and some inefficiencies in the Muon Tracking Chambers caused by faulty low-voltage connections. Fixing and consolidation efforts are still ongoing.

Thanks to new hardware installed previously and a redefined, successfully tested high-level trigger, the ALICE collaboration eagerly awaits the completion of the 2011 run analysis. “We expect the data collected in 2011 to significantly extend ALICE’s physics reach, particularly towards studying the thermodynamic properties of the quark-gluon plasma – the state of matter that is formed at the collision energy of the LHC,” says Yves Schutz, deputy ALICE spokesperson. “We have also observed intriguing results concerning the formation of particles issued from the plasma. These results need further analysis but we can already say that some of the physics processes observed at lower energy at RHIC, such as those involving the production of the J/ψ particle, do not seem to be reproduced in the same way at the LHC.”

In 2011, ALICE’s Physics Working Groups were reorganised to better meet the needs of the collaboration, which have evolved over time. The 2012 proton run is about to start and the experiment is ready to cope with the beam’s higher energy and intensity.

by CERN Bulletin and ALICE Matters