The last sector of the Large Hadron Collider, the worlds biggest, baddest particle accelerator, is beginning its slow cool down to near absolute zero.This is the final step before recommissioning of the broken accelerator can finally begin.

For those who don’t obsessively follow particle accelerators, the LHC uses superconducting magnets to steer protons around the machine. Those magnets must be kept at just 1.9 degrees above absolute zero to work. Getting anything that cold takes a lot of refrigerant: 10,000 tonnes of liquid nitrogen and 120 tonnes of liquid helium are used over the entire machine. It also takes time, and the cooling process will take weeks to complete.

When it’s all done though, LHC physicists can pick up where they left off last September. Hopefully we’ll see collisions by Christmas!

Credit: CERN