CERN's new plan for the next phase of the Large Hadron Collider: run the accelerator for up to two years at an energy of 3.5 TeV per beam. The run, expected to start at the end of this month, would end no later than December 2011 and be followed by a long shutdown to prepare the accelerator to run at its full energy of 7 TeV per beam.
The goal for the next two years is for the LHC experiments to collect a certain amount of data - one inverse femtobarn - at 3.5 TeV per beam. With that amount of data at that energy, the LHC experiments would be competitive with the experiments at Fermilab's Tevatron in the hunt for the big physics discoveries on the horizon: the Higgs boson and supersymmetry. If this goal is reached before December 2011, the accelerator and experiments may shut down earlier to begin the long process of readying the machine to run at the energy it was originally designed for.
The new schedule differs from that announced in August 2009 in two main ways: the length of the lower-energy run and its maximum energy. In August, it was announced that the LHC would begin its first run at 3.5 TeV per beam, perhaps increasing as high as 5 TeV per beam by the end of 2010. The accelerator would then shut down in 2011 in preparation for running at the full energy of 7 TeV per beam. The lower maximum energy decided on last week, and the longer running time at that lower energy, are a consequence of the problematic connections between superconducting LHC magnets. One such connection melted in September 2008 and led to one year of repairs, and during the long shutdown in 2012, virtually all such connections will be re-made.
This news was first reported Friday by John at Cosmic Variance, following the conclusion of the LHC Performance Workshop in Chamonix, France. The annual workshop provides the team operating CERN's accelerators a chance to retreat from the hustle and bustle of everyday work at the laboratory and focus on the near- and far-term future of the accelerator complex. All of the presentations from last week's workshop are available online. A summary of the workshop will be presented at CERN on February 5.
Update, February 3: CERN has officially confirmed the new LHC schedule.