The world’s largest particle accelerator is back in operation.

The Large Hadron Collider (LHC) at CERN was started up again over the weekend.  

The particle accelerator, which is located underground at the border of Switzerland and France near Geneva, is now working at half of its power.  

CERN scientists say they hope to keep the LHC at this speed until autumn of 2011.  

They say even at this power, they’ll be able to make discoveries, since this will be the fastest a particle accelerator has ever work.

The 6 billion franc LHC was launched in the autumn of 2008, but was shut down shortly after due to severe damage that required extensive repairs.