CERN reports that beams of protons and lead ions were injected into the Large Hadron Collider this weekend. The beams made a partial tour of the LHC in both directions before being dumped. This marks the first time in more than a year that particles have entered the LHC, and the first time ever that lead ions traveled through part of the LHC.
On Friday, protons and lead ions traveled clockwise through the LHC, passing through the ALICE detector before being dumped. On Saturday, protons traveled counterclockwise through the LHCb detector. These injection tests allow the scientists and engineers working on the LHC to check that the various sectors are prepared for the particle beam and that the beam is stable. Rama Calaga of Brookhaven National Laboratory was among the scientists monitoring the tests. Calaga noted that these tests were “a spectacular success and there were no surprises.”
The CERN news item also has a photo of the first beam of lead ions entering the LHC.